Fix README for 1.3.1

Merge branch 'master' into 1.3.branch
Add new options -cpu and -rom
2019-10-12 14:58:16 -07:00 · 2019-10-12 14:55:43 -07:00 · 2019-10-12 14:54:05 -07:00 · 2018-07-09 14:00:32 -07:00 · 2018-03-01 19:21:56 -08:00 · 2018-03-01 19:21:21 -08:00
122 changed files with 43097 additions and 1704 deletions
@@ -0,0 +1,5 @@
+eclipse.preferences.version=1
+encoding//src/main/java=UTF-8
+encoding//src/main/resources=UTF-8
+encoding//src/test/java=UTF-8
+encoding/<project>=UTF-8
@@ -0,0 +1,5 @@
+eclipse.preferences.version=1
+org.eclipse.jdt.core.compiler.codegen.targetPlatform=1.7
+org.eclipse.jdt.core.compiler.compliance=1.7
+org.eclipse.jdt.core.compiler.problem.forbiddenReference=warning
+org.eclipse.jdt.core.compiler.source=1.7
@@ -0,0 +1,4 @@
+activeProfiles=
+eclipse.preferences.version=1
+resolveWorkspaceProjects=true
+version=1
@@ -1,6 +1,6 @@
 The MIT License

-Copyright (c) 2008-2013 Seth J. Morabito <web@loomcom.com>
+Copyright (c) 2008-2014 Seth J. Morabito <web@loomcom.com>

 Permission is hereby granted, free of charge, to any person obtaining
 a copy of this software and associated documentation files (the
@@ -1,18 +1,13 @@
 SYMON - A 6502 System Simulator
 ===============================

-**NOTE: THIS SOFTWARE IS UNDER ACTIVE DEVELOPMENT. Feedback is welcome!**
+**Version:** 1.3.1

-**Version:** 0.9.1.0
-
-**Last Updated:** 29 December, 2013
-
-Copyright (c) 2013 Seth J. Morabito &lt;web@loomcom.com&gt;
+**Last Updated:** 12 October, 2019

 See the file COPYING for license.

-
-![Symon Simulator in Action] (https://github.com/sethm/symon/raw/master/screenshots/full.jpg)
+![Symon Simulator in Action](https://github.com/sethm/symon/raw/master/screenshots/full.jpg)

 ## 1.0 About

@@ -21,82 +16,119 @@ Technologies 6502 microprocessor and compatibles. Symon is implemented
 in Java. Its core goals are accuracy, ease of development, clear
 documentation, and extensive test suites for validating correctness.

-Symon simulates a complete system with a 1 MHz NMOS 6502, 32KB of RAM,
-16KB of ROM, a 6551 ACIA, a 6522 VIA, and a 6545 CRTC.
+Symon simulates a complete system with a 1 MHz NMOS 6502 or CMOS
+65C02, 32KB of RAM, 16KB of ROM, a MOS 6551 or Motorola 6850 ACIA, a
+MOS 6522 VIA, and an experimental 6545 CRTC.

 Symon has extensive unit tests to verify correctness, and fully passes
 Klaus Dormann's 6502 Functional Test Suite as of version 0.8.2
-(See [this thread on the 6502.org Forums] (http://forum.6502.org/viewtopic.php?f=2&t=2241)
+(See [this thread on the 6502.org Forums](http://forum.6502.org/viewtopic.php?f=2&t=2241)
 for more information about this functional test suite).

+Symon is under constant, active development. Feedback and patches
+are always welcome.
+
 ## 2.0 Requirements

-  - Java 1.5 or higher
+  - Java 1.8 or higher
  - Maven 2.0.x or higher (for building from source)
  - JUnit 4 or higher (for testing)

 ## 3.0 Features

-### 3.1 Memory Map
+Symon can simulate multiple 6502 based architectures. At present, three
+machines are implemented: Symon (the default), MULTICOMP, and a "Simple"
+machine useful for debugging.
+
+### 3.1 Memory Maps
+
+#### 3.1.1 Symon Memory Map

  - `$0000`--`$7FFF`: 32KB RAM
  - `$8000`--`$800F`: 6522 VIA
-  - `$8800`--`$8803`: 6551 ACIA (Serial Console)
-  - `$9000`--`$9001`: 6545 CRTC
+  - `$8800`--`$8803`: MOS 6551 ACIA (Serial Console)
+  - `$9000`--`$9001`: MOS 6545 CRTC
  - `$C000`--`$FFFF`: 16KB ROM

-The CRT Controller uses memory address `$7000` as the start of Video memory.
+The CRT Controller uses memory address `$7000` as the start of Video
+memory.
+
+#### 3.1.2 MULTICOMP Memory Map
+
+  - `$0000`--`$DFFF`: 56KB RAM
+  - `$E000`--`$FFFF`: 8KB ROM
+  - `$FFD0`--`$FFD1`: Motorola 6850 ACIA
+  - `$FFD8`--`$FFDF`: Controller for SD cards
+
+### 3.1.3 Simple Memory Map
+
+  - `$0000`--`$FFFF`: 64KB RAM

 ### 3.2 Serial Console and CPU Status

-![Serial Console] (https://github.com/sethm/symon/raw/master/screenshots/console.png)
+![Serial Console](https://github.com/sethm/symon/raw/master/screenshots/console.png)

 The main window of the simulator acts as the primary Input/Output
 system through a virtual serial terminal. The terminal is attached to
-a simulated MOS 6551 ACIA, including a programmable baud rate
-generator that tries to approximate the correct "feel" of the
-programmed baud rate. (The sample Enhanced BASIC ROM image is
-programmed for 9600 baud)
+a simulated ACIA, including a programmable baud rate generator that
+tries to approximate the correct "feel" of the programmed baud rate.
+(The sample Enhanced BASIC ROM image is programmed for 9600 baud)

 It also provides CPU status. Contents of the accumulator, index
 registers, processor status flags, disassembly of the instruction
 register, and stack pointer are all displayed.

-![Font Selection] (https://github.com/sethm/symon/raw/master/screenshots/font_selection.png)
+![Font Selection](https://github.com/sethm/symon/raw/master/screenshots/font_selection.png)

 The console supports font sizes from 10 to 20 points.

-### 3.3 16 KB ROM Loading
+### 3.3 ROM Loading

-![ROM Loading] (https://github.com/sethm/symon/raw/master/screenshots/load_rom.png)
+![ROM Loading](https://github.com/sethm/symon/raw/master/screenshots/load_rom.png)

-Symon can load any 16 KB (16384 bytes) ROM image from the "File"
-menu. The selected ROM will be placed in memory from locations `$C000`
-to `$FFFF`
+Symon can load any appropriately sized ROM image. The Symon
+architecture expects as 16KB (16384 byte) ROM image, while the
+MULTICOMP architecture expects an 8KB (8192 byte) ROM image. Images
+are loaded via the "Load ROM..." action in the "File" menu. The
+selected ROM file will be loaded into memory at the correct ROM base
+address.

 ### 3.4 Memory Window

-![Memory Window] (https://github.com/sethm/symon/raw/master/screenshots/memory_window.png)
+![Memory Window](https://github.com/sethm/symon/raw/master/screenshots/memory_window.png)

 Memory contents can be viewed (and edited) one page at a time through the Memory Window.

 ### 3.5 Trace Log

-![Trace Log] (https://github.com/sethm/symon/raw/master/screenshots/trace_log.png)
+![Trace Log](https://github.com/sethm/symon/raw/master/screenshots/trace_log.png)

-The last 20,000 execution steps are disassembled and logged to the Trace Log Window.
+The last 20,000 execution steps are disassembled and logged to the Trace Log
+Window.

-### 3.6 NEW - Experimental 6545 CRTC Video
+### 3.6 Simulator Speeds

-![Composite Video] (https://github.com/sethm/symon/raw/master/screenshots/video_window.png)
+![Speeds](https://github.com/sethm/symon/raw/master/screenshots/simulator_menu.png)

-This feature is highly experimental. It's possible to open a video window from the "View" menu.
-This window simulates the output of a MOS 6545 CRT Controller located at address `$9000` and
-`$9001`.
+Simulated speeds may be set from 1MHz to 8MHz.

-By default, the 40 x 25 character display uses video memory located at base address `$7000`.
-This means that the memory from address `$7000` (28672 decimal) to `$73E8` (29672 decimal)
-is directly mapped to video.
+### 3.7 Breakpoints
+
+![Breakpoints](https://github.com/sethm/symon/raw/master/screenshots/breakpoints.png)
+
+Breakpoints can be set and removed through the Breakpoints window.
+
+### 3.8 Experimental 6545 CRTC Video
+
+![Composite Video](https://github.com/sethm/symon/raw/master/screenshots/video_window.png)
+
+This feature is highly experimental. It's possible to open a video window
+from the "View" menu.  This window simulates the output of a MOS 6545 CRT
+Controller located at address `$9000` and `$9001`.
+
+By default, the 40 x 25 character display uses video memory located at base
+address `$7000`.  This means that the memory from address `$7000` (28672
+decimal) to `$73E8` (29672 decimal) is directly mapped to video.

  - Address Register (at address `$9000`)
  - R1: Horizontal Displayed Columns
@@ -109,27 +141,29 @@ is directly mapped to video.
  - R14: Cursor Position (High Byte)
  - R15: Cursor Position (Low Byte)

-Although the simulation is pretty good, there are a few key differences between
-the simulated 6545 and a real 6545:
+Although the simulation is pretty good, there are a few key differences
+between the simulated 6545 and a real 6545:

-  - The simulated 6545 supports only the straight binary addressing mode of the real 6545,
-    and not the Row/Column addressing mode.
-  - The simulated 6545 has full 16 bit addressing, where the real 6545 has only
-    a 14-bit address bus.
-  - The simulation is done at a whole-frame level, meaning that lots of
-    6545 programming tricks that were achieved by updating the frame address
-    during vertical and horizontal sync times are not achievable. There is no way
-    (for example) to change the Display Start Address (R12 and R13) while a
-    frame is being drawn.
+  - The simulated 6545 supports only the straight binary addressing
+    mode of the real 6545, and not the Row/Column addressing mode.
+
+  - The simulated 6545 has full 16 bit addressing, where the real 6545
+    has only a 14-bit address bus.
+
+  - The simulation is done at a whole-frame level, meaning that lots
+    of 6545 programming tricks that were achieved by updating the
+    frame address during vertical and horizontal sync times are not
+    achievable.  There is no way (for example) to change the Display Start
+    Address (R12 and R13) while a frame is being drawn.

 For more information on the 6545 CRTC and its programming model, please see the following resources

-  - [CRTC 6545/6845 Information (André Fachat)] (http://6502.org/users/andre/hwinfo/crtc/index.html)
-  - [CRTC Operation (André Fachat)] (http://www.6502.org/users/andre/hwinfo/crtc/crtc.html)
-  - [MOS 6545 Datasheet (PDF)] (http://www.6502.org/users/andre/hwinfo/crtc/crtc.html)
+  - [CRTC 6545/6845 Information (André Fachat)](http://6502.org/users/andre/hwinfo/crtc/index.html)
+  - [CRTC Operation (André Fachat)](http://www.6502.org/users/andre/hwinfo/crtc/crtc.html)
+  - [MOS 6545 Datasheet (PDF)](http://www.6502.org/users/andre/hwinfo/crtc/crtc.html)


-#### 3.6.1 Example BASIC Program to test Video
+#### 3.8.1 Example BASIC Program to test Video

 This program will fill the video screen with all printable characters.

@@ -152,26 +186,43 @@ Maven will build Symon, run unit tests, and produce a jar file in the
 `target` directory containing the compiled simulator.

 Symon is meant to be invoked directly from the jar file. To run with
-Java 1.5 or greater, just type:
+Java 1.8 or greater, just type:

-    $ java -jar symon-0.9.1.0.jar
+    $ java -jar symon-1.2.0.jar

 When Symon is running, you should be presented with a simple graphical
 interface.

+#### 4.1.1 Command Line Options
+
+Two command line options may be passed to the JAR file on startup,
+to specify machine type and CPU type. The options are:
+
+  - `-cpu 6502`: Use the NMOS 6502 CPU type by default.
+  - `-cpu 65c02`: Use the CMOS 65C02 CPU type by default.
+  - `-machine symon`: Use the **Symon** machine type by default.
+  - `-machine multicomp`: Use the **Multicomp** machine type by default.
+  - `-machine simple`: Use the **Simple** machine type by default.
+  - `-rom <file>`: Use the specified file as the ROM image.
+
 ### 4.2 ROM images

-The simulator requires a 16KB ROM image loaded at address `$C000` to `$FFFF` to
-work properly. Without a ROM in memory, the simulator will not be able to
-reset, since the reset vector for the 6502 is located in this address space.
+The simulator requires a ROM image loaded into memory to work
+properly. Without a ROM in memory, the simulator will not be able to
+reset, since the reset vector for the 6502 is located in the ROM
+address space.

-By default, any 16KB file named `rom.bin` that exists in the same directory
-where Symon is launched will be loaded as a ROM image. ROM images can also
-be swapped out at run-time with the "Load ROM Image..." in the File menu.
+By default, any file named `rom.bin` that exists in the same directory
+where Symon is launched will be loaded as a ROM image. ROM images can
+also be swapped out at run-time with the "Load ROM Image..." in the
+File menu.

-The "samples" directory contains a ROM image named 'ehbasic.rom', containing
-Lee Davison's Enhanced 6502 BASIC. This serves as a good starting point for
-exploration.
+The "samples" directory contains a ROM image for the Symon
+architecture named 'ehbasic.rom', containing Lee Davison's Enhanced
+6502 BASIC. This serves as a good starting point for exploration.
+
+*Note*: Presently, EhBASIC only works with the Symon machine
+ architecture, not with MULTICOMP.

 ### 4.3 Loading A Program

@@ -184,7 +235,7 @@ reset.

 There are two very simple sample program in the "samples" directory,
 for testing.
-  
+
 - 'echo.prg' will echo back anything typed at the console.

 - 'hello.prg' will continuously print "Hello, 6502 World!" to the console.
@@ -196,6 +247,38 @@ running.

 ## 5.0 Revision History

+  - **1.3.1:** 12 October, 2019 - Add support for new command line
+    option `-cpu <type>` to specify one of `6502` or `65c02` on startup,
+    and new option `-rom <file>` to specify a ROM file to load.
+
+  - **1.3.0:** 24 February, 2018 - Adds support for 65C02 opcodes.
+
+  - **1.2.1:** 8 January, 2016 - Remove dependency on Java 8. Now
+    supports compiling and running under Java 1.7.
+
+  - **1.2.0:** 3 January, 2016 - Add symbolic disassembly to breakpoints
+    window.
+
+  - **1.1.1:** 2 January, 2016 - Minor enhancement: Allows breakpoints
+    to be added with the Enter key.
+
+  - **1.1.0:** 31 December, 2015 - Fixed delay loop to better
+    simulate various clock speeds. Added ability to select clock
+    speed at runtime. Status display now shows the next instruction
+    to be executed, instead of the last instruction executed.
+    Added support for breakpoints.
+
+  - **1.0.0:** 10 August, 2014 - Added "Simple" machine
+    implementation, pure RAM with no IO. Added Klaus Dormann's
+    6502 Functional Tests for further machine verification (these
+    tests must be run in the "Simple" machine).
+
+  - **0.9.9.1:** 27 July, 2014 - Pressing 'Control' while clicking
+    'Reset' now performs a memory clear.
+
+  - **0.9.9:** 26 July, 2014 - MULTICOMP and multi-machine support
+    contributed by Maik Merten &lt;maikmerten@googlemail.com&gt;
+
  - **0.9.1:** 26 January, 2014 - Support for IRQ and NMI handling.

  - **0.9.0:** 29 December, 2013 - First pass at a 6545 CRTC simulation.
@@ -227,15 +310,21 @@ running.

  - **0.1:** 20 January, 2010

-## 6.0 To Do
+## 6.0 Roadmap
+
+  - **1.2:** Better breakpoint support. Symbolic debugging of breakpoints.
+
+  - **2.0:** Complete rewrite of the UI in JavaFX instead of Swing. Complete
+    assembler and disassembler built in. Ability to attach source code for
+    symbolic debugging.
+
+## 7.0 To Do

  - Feedback (in the form of dialogs, status bar, etc).

  - Better debugging tools from the UI, including breakpoints
    and disassembly.

-  - More accurate timing.
-
  - UI needs a ton more polish.

  - More extensive testing.
@@ -247,20 +336,33 @@ running.
  - Allow displaying ACIA status and dumping ACIA buffers, for
    debugging.

-## 7.0 Acknowledgements
+  - CRTC emulation is very naive. The whole frame is drawn in one
+    CPU step. This should be improved by drawing scan lines during
+    machine steps to approximate real NTSC/PAL refresh rates.
+
+  - Symbolic debugging.
+
+## 8.0 Copyright and Acknowledgements
+
+**Copyright (c) 2014 Seth J. Morabito &lt;web@loomcom.com&gt;**
+
+Portions Copyright (c) 2014 Maik Merten &lt;maikmerten@googlemail.com&gt;
+
+Additional components used in this project are copyright their respective owners.
+
+  - Enhanced 6502 BASIC Copyright (c) Lee Davison
+  - 6502 Functional Tests Copyright (c) Klaus Dormann
+  - JTerminal Copyright (c) Graham Edgecombe

 This project would not have been possible without the following resources:

-  - [Graham Edgecombe's JTerminal project] (https://github.com/grahamedgecombe/jterminal),
-    which forms the core of Symon's console.
-
-  - [Andrew Jacobs' 6502 Pages] (http://www.obelisk.demon.co.uk/6502/), for 
+  - [Andrew Jacobs' 6502 Pages](http://www.obelisk.demon.co.uk/6502/), for
    wonderfully detailed information about the 6502

-  - [Neil Parker's "The 6502/65C02/65C816 Instruction Set Decoded"] (http://www.llx.com/~nparker/a2/opcodes.html),
+  - [Neil Parker's "The 6502/65C02/65C816 Instruction Set Decoded"](http://www.llx.com/~nparker/a2/opcodes.html),
    for information about how instructions are coded

-## 8.0 Licensing
+## 9.0 Licensing

 Symon is free software.  It is distributed under the MIT License.
 Please see the file 'COPYING' for full details of the license.
@@ -4,7 +4,7 @@
    <groupId>com.loomcom.symon</groupId>
    <artifactId>symon</artifactId>
    <packaging>jar</packaging>
-    <version>0.9.1.0</version>
+    <version>1.3.1</version>
    <name>symon</name>
    <url>http://www.loomcom.com/symon</url>
    <properties>
@@ -15,72 +15,37 @@
            UTF-8
        </project.reporting.outputEncoding>
    </properties>
-    <repositories>
-        <repository>
-            <id>jline</id>
-            <name>JLine Project Repository</name>
-            <url>http://jline.sourceforge.net/m2repo</url>
-        </repository>
-        <!-- Loomcom's Maven2 repository for JTerminal -->
-        <repository>
-            <releases>
-                <enabled>true</enabled>
-                <updatePolicy>always</updatePolicy>
-                <checksumPolicy>fail</checksumPolicy>
-            </releases>
-            <id>com.loomcom</id>
-            <name>Loom Communications Maven2 Repository</name>
-            <url>http://www.loomcom.com/maven2</url>
-            <layout>default</layout>
-        </repository>
-    </repositories>
    <dependencies>
+        <dependency>
+            <groupId>ch.qos.logback</groupId>
+            <artifactId>logback-classic</artifactId>
+            <version>1.2.3</version>
+        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
-            <version>4.11</version>
+            <version>4.12</version>
            <scope>test</scope>
        </dependency>
-        <dependency>
-            <groupId>com.grahamedgecombe.jterminal</groupId>
-            <artifactId>jterminal</artifactId>
-            <version>1.0.2.3-loomcom</version>
-        </dependency>
        <dependency>
            <groupId>org.mockito</groupId>
            <artifactId>mockito-all</artifactId>
-            <version>1.9.5</version>
+            <version>1.10.19</version>
            <scope>test</scope>
        </dependency>
+        <dependency>
+            <groupId>commons-cli</groupId>
+            <artifactId>commons-cli</artifactId>
+            <version>1.4</version>
+        </dependency>
    </dependencies>

    <build>
        <plugins>
-            <plugin>
-                <artifactId>maven-resources-plugin</artifactId>
-                <version>2.6</version>
-                <executions>
-                    <execution>
-                        <id>copy-resources</id>
-                        <phase>process-resources</phase>
-                        <goals>
-                            <goal>copy-resources</goal>
-                        </goals>
-                        <configuration>
-                            <outputDirectory>${basedir}/target/classes/com/loomcom/symon/ui/images</outputDirectory>
-                            <resources>
-                                <resource>
-                                    <directory>src/main/java/com/loomcom/symon/ui/images</directory>
-                                </resource>
-                            </resources>
-                        </configuration>
-                    </execution>
-                </executions>
-            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-assembly-plugin</artifactId>
-                <version>2.4</version>
+                <version>2.6</version>
                <configuration>
                    <descriptorRefs>
                        <descriptorRef>jar-with-dependencies</descriptorRef>
@@ -88,7 +53,7 @@
                    <appendAssemblyId>false</appendAssemblyId>
                    <archive>
                        <manifest>
-                            <mainClass>com.loomcom.symon.Simulator</mainClass>
+                            <mainClass>com.loomcom.symon.Main</mainClass>
                        </manifest>
                    </archive>
                </configuration>
@@ -104,11 +69,11 @@
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
-                <version>3.1</version>
+                <version>3.7.0</version>
                <configuration>
                    <compilerArgument>-Xlint:unchecked</compilerArgument>
-                    <source>1.6</source>
-                    <target>1.6</target>
+                    <source>1.7</source>
+                    <target>1.7</target>
                </configuration>
            </plugin>

@@ -116,7 +81,7 @@
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
-                <version>2.4</version>
+                <version>2.6</version>
                <configuration>
                    <archive>
                        <manifest>
@@ -7,7 +7,7 @@ echo_irq: echo_irq.o
 	$(LD) -C symon.config -vm -m echo_irq.map -o echo_irq.rom echo_irq.o

 echo_irq.o:
-	$(CA) --listing -o echo_irq.o echo_irq.asm
+	$(CA) --listing echo_irq.lst -o echo_irq.o echo_irq.asm

 clean:
 	rm -f *.o *.rom *.map *.lst
@@ -1,5 +1,5 @@
 MEMORY {
-RAM1: start = $0000, size = $8000;
+RAM1: start = $0000, size = $8000 - __STACKSIZE__;
 ROM1: start = $C000, size = $3FFA, fill = yes;
 ROMV: start = $FFFA, size = $6, file = %O, fill = yes;
 }
@@ -11,6 +11,6 @@ VECTORS:  load = ROMV, type = ro;
 }

 SYMBOLS {
-__STACKSIZE__ = $0300;
+__STACKSIZE__: type = weak, value = $0300;
 }

@@ -7,7 +7,7 @@ ehbasic: ehbasic.o
 	$(LD) -C symon.config -vm -m ehbasic.map -o ehbasic.rom ehbasic.o

 ehbasic.o:
-	$(CA) --listing -o ehbasic.o min_mon.asm
+	$(CA) --listing ehbasic.lst -o ehbasic.o min_mon.asm

 clean:
 	rm -f *.o *.rom *.map *.lst
@@ -150,7 +150,7 @@ END_CODE
 ; sign on string

 LAB_mess
-	.byte	$0D,$0A,"Symon (c) 2008-2013, Seth Morabito"
+	.byte	$0D,$0A,"Symon (c) 2008-2014, Seth Morabito"
 	.byte   $0D,$0A,"Enhanced 6502 BASIC 2.22 (c) Lee Davison"
 	.byte   $0D,$0A,"[C]old/[W]arm ?",$00

@@ -1,5 +1,5 @@
 MEMORY {
-RAM1: start = $0000, size = $8000;
+RAM1: start = $0000, size = $8000 - __STACKSIZE__;
 ROM1: start = $C000, size = $3F00, fill = yes;
 MONITOR: start = $FF00, size = $FA, fill = yes;
 ROMV: start = $FFFA, size = $6, file = %O, fill = yes;
@@ -13,6 +13,6 @@ VECTORS:  load = ROMV, type = ro;
 }

 SYMBOLS {
-__STACKSIZE__ = $0300;
+__STACKSIZE__: type = weak, value = $0300;
 }

@@ -0,0 +1,4 @@
+*.rom
+*.lst
+*.map
+*.o
@@ -0,0 +1,13 @@
+CA=ca65
+LD=ld65
+
+all: ehbasic
+
+ehbasic: ehbasic.o
+	$(LD) -C symon.config -vm -m ehbasic.map -o ehbasic.rom ehbasic.o
+
+ehbasic.o:
+	$(CA) --listing ehbasic.lst -o ehbasic.o min_mon.asm
+
+clean:
+	rm -f *.o *.rom *.map *.lst
@@ -0,0 +1,85 @@
+This directoy contains a very slightly modified version of EhBASIC 2.22
+to support the Symon simulator.
+
+Usage
+-----
+
+The pre-assemled ROM image 'ehbasic.rom' in the "samples" directory is all you
+need unless you want to rebuild this source code.
+
+Just copy the image 'ehbasic.rom' to the directory where you run Symon, and
+rename the file to 'rom.bin'. It will be loaded at memory location $D000 when
+the simulator starts up. Click "Run" and you'll be presented with BASIC.
+
+At the first prompt, type 'C' for a Cold Start
+
+When prompted for free memory, type: $C000
+
+Note that EhBASIC only accepts upper case input, so you'll need to use caps
+lock (the cruise control for cool) to really make the most of it.
+
+
+Building
+--------
+
+
+To build it, you'll need the CC65 tool chain from http://www.cc65.org/
+and a suitable version of 'make'. Just typing:
+
+   % make
+   
+in this directory should re-build everything. You'll get a listing,
+some object files, and the ROM image itself.
+
+
+Changes from the EhBASIC 2.22
+-----------------------------
+
+  - Minor syntax changes to allow assembly with the cc65 tool chain.
+
+  - Memory map modified for Symon.
+
+  - At reset, configure the 6551 ACIA for 8-N-1, 2400 baud.
+ 
+  - Monitor routines 'ACIAin' and 'ACIAout' modified for the 6551 ACIA.
+    Specifically, reading and writing will check the 6551 status register for
+    the status of rx and tx registers before receive or transmit.
+
+EhBASIC is copyright Lee Davison <leeedavison@googlemail.com>
+
+My changes are so slight that I hesitate to even say this, but for "CYA"
+reasons:
+
+Changes are copyright Seth Morabito <web@loomcom.com> and are distributed under
+the same license as EhBASIC. I claim no commercial interest whatsoever. Any
+commercial use must be negotiated directly with Lee Davison.
+
+
+Original EhBASIC 2.22 README
+----------------------------
+
+ Enhanced BASIC is a BASIC interpreter for the 6502 family microprocessors. It
+ is constructed to be quick and powerful and easily ported between 6502 systems.
+ It requires few resources to run and includes instructions to facilitate easy
+ low level handling of hardware devices. It also retains most of the powerful
+ high level instructions from similar BASICs.
+
+ EhBASIC is free but not copyright free. For non commercial use there is only one
+ restriction, any derivative work should include, in any binary image distributed,
+ the string "Derived from EhBASIC" and in any distribution that includes human
+ readable files a file that includes the above string in a human readable form
+ e.g. not as a comment in an HTML file.
+
+ For commercial use please contact me,  Lee Davison, at leeedavison@googlemail.com
+ for conditions.
+
+ For more information on EhBASIC, other versions of EhBASIC and other projects
+ please visit my site at ..
+
+	 http://mycorner.no-ip.org/index.html
+
+
+ P.S. c't magazin, henceforth refered to as "those thieving german bastards", are
+ prohibited from using this or any version of EhBASIC for any of their projects
+ or products. The excuse "we don't charge people for it" doesn't wash, it adds
+ value to your product so you owe me.
@@ -0,0 +1,449 @@
+
+; minimal monitor for EhBASIC and 6502 simulator V1.05
+
+; To run EhBASIC on the simulator load and assemble [F7] this file, start the simulator
+; running [F6] then start the code with the RESET [CTRL][SHIFT]R. Just selecting RUN
+; will do nothing, you'll still have to do a reset to run the code.
+
+	.feature labels_without_colons
+	.include "basic.asm"
+
+; put the IRQ and MNI code in RAM so that it can be changed
+
+IRQ_vec	= VEC_SV+2		; IRQ code vector
+NMI_vec	= IRQ_vec+$0A	; NMI code vector
+
+; setup for the 6502 simulator environment
+
+IO_AREA		= $8800
+ACIAdata	= IO_AREA	; simulated ACIA r/w port
+ACIAstatus	= IO_AREA+1
+ACIAcommand	= IO_AREA+2
+ACIAcontrol	= IO_AREA+3
+
+	CRTC_A	= $9000		; CRTC register select
+	CRTC_C	= $9001		; CRTC register IO
+	CADDR_L	= $E0		; Cursor address (low)
+	CADDR_H	= $E1		; Cursor address (high)
+	C_COL	= $E2		; Cursor column
+	C_ROW	= $E3		; Cursor row
+	COUTC	= $E4		; Temp storage for char out.
+	R_STRT	= $E5		; E5,E6 contains starting address of
+				; current row
+	R_NXT	= $E7		; E7,E8 contains starting address of
+				; next row
+
+	N_ROWS	= 24
+	N_COLS	= 40
+
+
+; now the code. all this does is set up the vectors and interrupt code
+; and wait for the user to select [C]old or [W]arm start. nothing else
+; fits in less than 128 bytes
+
+.segment "MONITOR"
+	.org	$FC00		; pretend this is in a 1/8K ROM
+
+; reset vector points here
+
+RES_vec:
+	CLD			; clear decimal mode
+	LDX	#$FF		; empty stack
+	TXS			; set the stack
+
+	;; Initialize the CRTC
+	LDA	#$01
+	STA	CRTC_A
+	LDA	#N_COLS		; 40 columns
+	STA	CRTC_C
+	LDA	#$06
+	STA	CRTC_A
+	LDA	#N_ROWS		; 24 rows
+	STA	CRTC_C
+	LDA	#$70
+	STA	CADDR_H
+	LDA	#$00
+	STA	CADDR_L
+	STA	C_ROW
+	STA	C_COL
+	JSR	CLRVID
+	;; TODO: Initialize params on CRTC
+
+; Initialize the ACIA
+ACIA_init:
+	LDA	#$00
+	STA	ACIAstatus		; Soft reset
+	LDA	#$0B
+	STA	ACIAcommand		; Parity disabled, IRQ disabled
+	LDA	#$1E
+	STA	ACIAcontrol		; Set output for 8-N-1 9600
+
+; set up vectors and interrupt code, copy them to page 2
+
+	LDY	#END_CODE-LAB_vec	; set index/count
+LAB_stlp:
+	LDA	LAB_vec-1,Y		; get byte from interrupt code
+	STA	VEC_IN-1,Y		; save to RAM
+	DEY				; decrement index/count
+	BNE	LAB_stlp		; loop if more to do
+
+; now do the signon message, Y = $00 here
+
+LAB_signon:
+	LDA	LAB_mess,Y	; get byte from sign on message
+	BEQ	LAB_nokey	; exit loop if done
+
+	JSR	V_OUTP		; output character
+	INY			; increment index
+	BNE	LAB_signon	; loop, branch always
+
+LAB_nokey:
+	JSR	V_INPT		; call scan input device
+	BCC	LAB_nokey	; loop if no key
+
+	AND	#$DF		; mask xx0x xxxx, ensure upper case
+	CMP	#'W'		; compare with [W]arm start
+	BEQ	LAB_dowarm	; branch if [W]arm start
+
+	CMP	#'C'		; compare with [C]old start
+	BNE	RES_vec		; loop if not [C]old start
+
+	JMP	LAB_COLD	; do EhBASIC cold start
+
+LAB_dowarm:
+	JMP	LAB_WARM	; do EhBASIC warm start
+
+
+ACIAout:
+
+	PHA
+@loop:	LDA	ACIAstatus
+	AND	#$10
+	BEQ	@loop		; Wait for buffer to empty
+	PLA
+	STA	ACIAdata
+	RTS
+
+;;; Byte out to the CRTC
+;;;
+;;; 1. Increment cursor position.
+;;; 2. Scroll if necessary.
+;;; 3. Store new cursor position in CRTC.
+
+CRTCout:
+	JSR	ACIAout		; Also echo to terminal for debugging.
+
+	;; In parallel, we're maintaining two states:
+	;;    - The address of the cursor, and
+	;;    - The Column/Row of the cursor.
+	;;
+	;; The latter state is used to handle scrolling and
+	;; for knowing how far to back up the cursor
+	;; for a carriage-return.
+
+	;; Backspace
+	CMP	#$08
+	BEQ	DO_BS
+	;; Line Feed
+	CMP	#$0a
+	BEQ	DO_LF
+	;; Carriage Return
+	CMP	#$0d
+	BEQ	DO_CR
+	;; Any other character...
+	STA	COUTC		; Store the character going out
+	JSR	COUT1		; Output it where the cursor is.
+	;; We might need to scroll...
+	LDA	C_ROW
+	CMP	#N_ROWS-1
+	BNE	@noscr
+	LDA	C_COL
+	CMP	#N_COLS-1
+	BNE	@noscr
+	;; ... yup, we DO need to scroll.
+	JSR	DO_SCROLL
+	RTS
+@noscr:	JSR	INC_CADDR
+	INC	C_COL
+	JSR	SET_CURSOR
+	RTS
+
+	;; Handle a back-space character.
+DO_BS:	LDA	C_COL
+	BNE	@l1		; Skip next bit
+	LDA	#N_COLS-1
+	STA	C_COL
+	BNE	@l2
+@l1:	DEC	C_COL
+@l2:	JSR	DEC_CADDR	; Back up
+	JSR	SET_CURSOR
+
+@l3:	LDA	#$20
+	STA	COUTC		; Echo a space ($20)
+	JSR	COUT1
+	RTS
+
+DO_LF:	RTS			; Just swallow LF. CR emulates it.
+
+DO_CR:	SEC
+	LDA	CADDR_L		; 1. Carriage return to start of row.
+	SBC	C_COL
+	STA	CADDR_L
+	LDA	CADDR_H
+	SBC	#$00		; Will decrement H if carry was left
+				; set.
+	STA	CADDR_H
+
+	;; 1. Are we on the last row? Scroll.
+	LDA	C_ROW
+	CMP	#N_ROWS-1
+	BNE	@inc
+	JSR	DO_SCROLL
+	RTS
+
+@inc:	JSR	INCROW
+
+@lf:	CLC
+	LDA	CADDR_L
+	ADC	#$28		; Now add $28
+	STA	CADDR_L
+	LDA	CADDR_H
+	ADC	#$00		; Will increment if carry was set
+	STA	CADDR_H
+
+	LDA	#$00		; Reset cursor row to 0
+	STA	C_COL
+	JSR	SET_CURSOR
+	RTS
+
+SET_CURSOR:
+	LDA	#14
+	STA	CRTC_A
+	LDA	CADDR_H
+	STA	CRTC_C
+	LDA	#15
+	STA	CRTC_A
+	LDA	CADDR_L
+	STA	CRTC_C
+	RTS
+
+	;; Increment C_ROW and put new
+	;; line start address in R_STRT,R_STRT+1
+INCROW:	TYA
+	PHA
+	INC	C_ROW
+	BNE	DECR2	      ; Share code with DECROW
+
+	;; Decrement C_ROW and put new
+	;; line start address in R_STRT,R_STRT+1
+DECROW:	TYA
+	PHA
+	DEC	C_ROW
+DECR2:	JSR	SETRSTRT
+	PLA
+	TAY
+	RTS
+
+	;; Send the cursor home to the start of the line
+HOME:
+	LDY	C_ROW
+	LDA	CRA_LO,Y
+	STA	CADDR_L
+	LDA	CRA_HI,Y
+	STA	CADDR_H
+	LDA	#$00
+	STA	C_COL
+	RTS
+
+	;; Set the start address of the current row
+SETRSTRT:
+	LDY	C_ROW
+	LDA	CRA_LO,Y
+	STA	R_STRT
+	LDA	CRA_HI,Y
+	STA	R_STRT+1
+	RTS
+
+	;; Clear the current video line
+CLRLN:	LDA	#$20
+	LDY	#$00
+@l1:	STA	(R_STRT),Y
+	INY
+	CPY	#N_COLS
+	BNE	@l1
+	RTS
+
+	;; Clear the video window and put the cursor at the home
+	;; position
+CLRVID:
+	LDA	#$20
+	LDX	#N_ROWS-1
+@l1:	STX	C_ROW
+	JSR	SETRSTRT
+	JSR	CLRLN
+	DEX
+	BPL	@l1
+	RTS
+
+	;; Handle a scroll request.
+	;;
+	;; The cursor could be anywhere on the line when this scroll
+	;; request comes in.
+DO_SCROLL:
+	PHA
+	TYA
+	PHA
+	TXA
+	PHA
+
+	;; The idea here is to copy each line to the line above it
+	LDX	#$00
+
+@l1:	LDA	CRA_LO,X
+	STA	R_STRT
+	LDA	CRA_HI,X
+	STA	R_STRT+1
+
+	INX
+
+	LDA	CRA_LO,X
+	STA	R_NXT
+	LDA	CRA_HI,X
+	STA	R_NXT+1
+
+	LDY	#0
+@l2:	LDA	(R_NXT),Y
+	STA	(R_STRT),Y
+	INY
+	CPY	#N_COLS
+	BNE	@l2
+
+	CPX	#N_ROWS
+	BNE	@l1
+
+	;; Clear the line the cursor occupies.
+	JSR	CLRLN
+
+	;; Move the cursor to the beginning of the line
+	JSR	HOME
+	JSR	SET_CURSOR
+
+	PLA
+	TAX
+	PLA
+	TAY			; Restore Y
+	PLA
+	RTS
+
+	;; Decrement the cursor address
+INC_CADDR:
+	INC	CADDR_L
+	BNE	@l1		; Did we increment to 0?
+	INC	CADDR_H		; Yes, also increment high
+@l1:	RTS
+
+	;; Increment the cursor address
+DEC_CADDR:
+	CMP	CADDR_L		; Is low alrady 0?
+	BNE	@l1
+	DEC	CADDR_H		; Yes, decrement high
+@l1:	DEC	CADDR_L
+	RTS
+
+COUT1:
+	TYA
+	PHA			; Save Y
+	LDY	#$00
+	LDA	COUTC
+	STA	(CADDR_L),Y
+	PLA
+	TAY			; Restore Y
+	RTS
+
+;;;
+;;; byte in from ACIA. This subroutine will also force
+;;; all lowercase letters to be uppercase, because EhBASIC
+;;; only understands upper-case tokens
+;;;
+ACIAin:
+	LDA	ACIAstatus	; Read 6551 status
+	AND	#$08		;
+	BEQ	LAB_nobyw	; If rx buffer empty, no byte
+
+	LDA	ACIAdata	; Read byte from 6551
+	CMP	#'a'		; Is it < 'a'?
+	BCC	@done		; Yes, we're done
+	CMP	#'{'		; Is it >= '{'?
+	BCS	@done		; Yes, we're done
+	AND	#$5f		; Otherwise, mask to uppercase
+@done:
+	SEC			; Flag byte received
+	RTS
+
+LAB_nobyw:
+	CLC			; flag no byte received
+no_load:			; empty load vector for EhBASIC
+no_save:			; empty save vector for EhBASIC
+	RTS
+
+; vector tables
+
+LAB_vec:
+	.word	ACIAin		; byte in from simulated ACIA
+	.word	CRTCout		; byte out to simulated ACIA
+	.word	no_load		; null load vector for EhBASIC
+	.word	no_save		; null save vector for EhBASIC
+
+; EhBASIC IRQ support
+
+IRQ_CODE:
+	PHA			; save A
+	LDA	IrqBase		; get the IRQ flag byte
+	LSR			; shift the set b7 to b6, and on down ...
+	ORA	IrqBase		; OR the original back in
+	STA	IrqBase		; save the new IRQ flag byte
+	PLA			; restore A
+	RTI
+
+; EhBASIC NMI support
+
+NMI_CODE:
+	PHA			; save A
+	LDA	NmiBase		; get the NMI flag byte
+	LSR			; shift the set b7 to b6, and on down ...
+	ORA	NmiBase		; OR the original back in
+	STA	NmiBase		; save the new NMI flag byte
+	PLA			; restore A
+	RTI
+
+END_CODE:
+
+
+;;; CRTC row addresses: HIGH
+CRA_HI:
+	.byte	$70,$70,$70,$70,$70,$70,$70,$71
+	.byte	$71,$71,$71,$71,$71,$72,$72,$72
+	.byte	$72,$72,$72,$72,$73,$73,$73,$73
+
+
+;;; CRTC row addresses: LOW
+CRA_LO:
+	.byte	$00,$28,$50,$78,$A0,$C8,$F0,$18
+	.byte	$40,$68,$90,$B8,$E0,$08,$30,$58
+	.byte	$80,$A8,$D0,$F8,$20,$48,$70,$98
+
+; sign on string
+LAB_mess:
+	.byte	$0D,$0A,"SYMON (C) 2008-2014, SETH MORABITO"
+	.byte   $0D,$0A,"ENHANCED 6502 BASIC 2.22 (C) LEE DAVISON"
+	.byte   $0D,$0A,"[C]OLD/[W]ARM ?",$00
+
+
+; system vectors
+
+.segment "VECTORS"
+	.org	$FFFA
+
+	.word	NMI_vec		; NMI vector
+	.word	RES_vec		; RESET vector
+	.word	IRQ_vec		; IRQ vector
@@ -0,0 +1,18 @@
+MEMORY {
+RAM1: start = $0000, size = $8000 - __STACKSIZE__;
+ROM1: start = $C000, size = $3C00, fill = yes;
+MONITOR: start = $FC00, size = $3FA, fill = yes;
+ROMV: start = $FFFA, size = $6, file = %O, fill = yes;
+}
+
+SEGMENTS {
+CODE:     load = ROM1, type = ro;
+DATA:     load = ROM1, type = ro;
+MONITOR:  load = MONITOR, type = ro;
+VECTORS:  load = ROMV, type = ro;
+}
+
+SYMBOLS {
+__STACKSIZE__: type = weak, value = $0300;
+}
+
@@ -0,0 +1,85 @@
+package com.loomcom.symon;
+
+import com.loomcom.symon.exceptions.MemoryAccessException;
+import com.loomcom.symon.util.Utils;
+
+import javax.swing.table.AbstractTableModel;
+import java.util.ArrayList;
+import java.util.TreeSet;
+
+public class Breakpoints extends AbstractTableModel {
+
+    private TreeSet<Integer> breakpoints;
+    private Simulator simulator;
+
+    public Breakpoints(Simulator simulator) {
+        this.breakpoints = new TreeSet<>();
+        this.simulator = simulator;
+    }
+
+    public boolean contains(int address) {
+        return this.breakpoints.contains(address);
+    }
+
+    public void addBreakpoint(int address) {
+        this.breakpoints .add(address);
+        fireTableDataChanged();
+    }
+
+    public void removeBreakpoint(int address) {
+        this.breakpoints.remove(address);
+        fireTableDataChanged();
+    }
+
+    public void removeBreakpointAtIndex(int index) {
+        if (index < 0) {
+            return;
+        }
+
+        ArrayList<Integer> values = new ArrayList<>(breakpoints);
+        int value = values.get(index);
+        this.breakpoints.remove(value);
+        fireTableDataChanged();
+    }
+
+    public void refresh() {
+        fireTableDataChanged();
+    }
+
+    @Override
+    public String getColumnName(int index) {
+        if (index == 0) {
+            return "Address";
+        } else {
+            return "Inst";
+        }
+    }
+
+    @Override
+    public int getRowCount() {
+        return breakpoints.size();
+    }
+
+    @Override
+    public int getColumnCount() {
+        return 2;
+    }
+
+    @Override
+    public Object getValueAt(int rowIndex, int columnIndex) {
+        ArrayList<Integer> values = new ArrayList<>(breakpoints);
+
+        if (columnIndex == 0) {
+            return "$" + Utils.wordToHex(values.get(rowIndex));
+        } else if (columnIndex == 1) {
+            int address = values.get(rowIndex);
+            try {
+                return simulator.disassembleOpAtAddress(address);
+            } catch (MemoryAccessException ex) {
+                return "???";
+            }
+        } else {
+            return null;
+        }
+    }
+}
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008-2013 Seth J. Morabito <sethm@loomcom.com>
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
@@ -27,6 +27,12 @@ import com.loomcom.symon.devices.Device;
 import com.loomcom.symon.exceptions.MemoryAccessException;
 import com.loomcom.symon.exceptions.MemoryRangeException;

+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.HashMap;
+import java.util.Map;
+
 import java.util.SortedSet;
 import java.util.TreeSet;

@@ -37,7 +43,7 @@ public class Bus {

    // The default address at which to load programs
    public static int DEFAULT_LOAD_ADDRESS = 0x0200;
-	
+
    // By default, our bus starts at 0, and goes up to 64K
    private int startAddress = 0x0000;
    private int endAddress = 0xffff;
@@ -45,15 +51,19 @@ public class Bus {
    // The CPU
    private Cpu cpu;

-    // Ordered list of IO devices.
-    private SortedSet<Device> devices;
+    // Ordered sets of IO devices, associated with their priority
+    private Map<Integer, SortedSet<Device>> deviceMap;
+
+    // an array for quick lookup of adresses, brute-force style
+    private Device[] deviceAddressArray;
+

    public Bus(int size) {
        this(0, size - 1);
    }

    public Bus(int startAddress, int endAddress) {
-        this.devices = new TreeSet<Device>();
+        this.deviceMap = new HashMap<>();
        this.startAddress = startAddress;
        this.endAddress = endAddress;
    }
@@ -66,38 +76,72 @@ public class Bus {
        return endAddress;
    }

-    /**
-     * Add a device to the bus. Throws a MemoryRangeException if the device overlaps with any others.
-     *
-     * @param device
-     * @throws MemoryRangeException
-     */
-    public void addDevice(Device device) throws MemoryRangeException {
-        // Make sure there's no memory overlap.
-        MemoryRange memRange = device.getMemoryRange();
-        for (Device d : devices) {
-            if (d.getMemoryRange().overlaps(memRange)) {
-                throw new MemoryRangeException("The device being added at " +
-                                               String.format("$%04X", memRange.startAddress()) +
-                                               " overlaps with an existing " +
-                                               "device, '" + d + "'");
+    private void buildDeviceAddressArray() {
+        int size = (this.endAddress - this.startAddress) + 1;
+        deviceAddressArray = new Device[size];
+
+        // getDevices() provides an OrderedSet with devices ordered by priorities
+        for (Device device : getDevices()) {
+            MemoryRange range = device.getMemoryRange();
+            for (int address = range.startAddress; address <= range.endAddress; ++address) {
+                deviceAddressArray[address - this.startAddress] = device;
            }
        }

-        // Add the device
-        device.setBus(this);
-        devices.add(device);
    }

+    /**
+     * Add a device to the bus.
+     *
+     * @param device   Device to add
+     * @param priority Bus prioirity.
+     * @throws MemoryRangeException
+     */
+    public void addDevice(Device device, int priority) throws MemoryRangeException {
+
+        MemoryRange range = device.getMemoryRange();
+
+        if (range.startAddress() < this.startAddress || range.startAddress() > this.endAddress) {
+            throw new MemoryRangeException("start address of device " + device.getName() + " does not fall within the address range of the bus");
+        }
+
+        if (range.endAddress() < this.startAddress || range.endAddress() > this.endAddress) {
+            throw new MemoryRangeException("end address of device " + device.getName() + " does not fall within the address range of the bus");
+        }
+
+        SortedSet<Device> deviceSet = deviceMap.get(priority);
+
+        if (deviceSet == null) {
+            deviceSet = new TreeSet<>();
+            deviceMap.put(priority, deviceSet);
+        }
+
+        device.setBus(this);
+        deviceSet.add(device);
+        buildDeviceAddressArray();
+    }
+
+    /**
+     * Add a device to the bus. Throws a MemoryRangeException if the device overlaps with any others.
+     *
+     * @param device Device to add
+     * @throws MemoryRangeException
+     */
+    public void addDevice(Device device) throws MemoryRangeException {
+        addDevice(device, 0);
+    }
+
+
    /**
     * Remove a device from the bus.
     *
-     * @param device
+     * @param device Device to remove
     */
    public void removeDevice(Device device) {
-        if (devices.contains(device)) {
-            devices.remove(device);
+        for (SortedSet<Device> deviceSet : deviceMap.values()) {
+            deviceSet.remove(device);
        }
+        buildDeviceAddressArray();
    }

    public void addCpu(Cpu cpu) {
@@ -111,43 +155,39 @@ public class Bus {
     * device.
     */
    public boolean isComplete() {
-        // Empty maps cannot be complete.
-        if (devices.isEmpty()) {
-            return false;
+        if (deviceAddressArray == null) {
+            buildDeviceAddressArray();
        }

-        // Loop over devices and add their size
-        int filledMemory = 0;
-        for (Device d : devices) {
-            filledMemory += d.getSize();
-        }
-
-        // Returns if the total size of the devices fill the bus' memory space
-        return filledMemory == endAddress - startAddress + 1;
-    }
-
-    public int read(int address) throws MemoryAccessException {
-        for (Device d : devices) {
-            MemoryRange range = d.getMemoryRange();
-            if (range.includes(address)) {
-                // Compute offset into this device's address space.
-                int devAddr = address - range.startAddress();
-                return d.read(devAddr);
+        for (int address = startAddress; address <= endAddress; ++address) {
+            if (deviceAddressArray[address - startAddress] == null) {
+                return false;
            }
        }
+
+        return true;
+    }
+
+    public int read(int address, boolean cpuAccess) throws MemoryAccessException {
+        Device d = deviceAddressArray[address - this.startAddress];
+        if (d != null) {
+            MemoryRange range = d.getMemoryRange();
+            int devAddr = address - range.startAddress();
+            return d.read(devAddr, cpuAccess) & 0xff;
+        }
+
        throw new MemoryAccessException("Bus read failed. No device at address " + String.format("$%04X", address));
    }

    public void write(int address, int value) throws MemoryAccessException {
-        for (Device d : devices) {
+        Device d = deviceAddressArray[address - this.startAddress];
+        if (d != null) {
            MemoryRange range = d.getMemoryRange();
-            if (range.includes(address)) {
-                // Compute offset into this device's address space.
-                int devAddr = address - range.startAddress();
-                d.write(devAddr, value);
-                return;
-            }
+            int devAddr = address - range.startAddress();
+            d.write(devAddr, value);
+            return;
        }
+
        throw new MemoryAccessException("Bus write failed. No device at address " + String.format("$%04X", address));
    }

@@ -176,8 +216,20 @@ public class Bus {
    }

    public SortedSet<Device> getDevices() {
-        // Expose a copy of the device list, not the original
-        return new TreeSet<Device>(devices);
+        // create an ordered set of devices, ordered by device priorities
+        SortedSet<Device> devices = new TreeSet<>();
+
+        List<Integer> priorities = new ArrayList<>(deviceMap.keySet());
+        Collections.sort(priorities);
+
+        for (int priority : priorities) {
+            SortedSet<Device> deviceSet = deviceMap.get(priority);
+            for (Device device : deviceSet) {
+                devices.add(device);
+            }
+        }
+
+        return devices;
    }

    public Cpu getCpu() {
@@ -0,0 +1,177 @@
+package com.loomcom.symon;
+
+import com.loomcom.symon.util.Utils;
+
+/**
+ * A compact, struct-like representation of CPU state.
+ */
+public class CpuState {
+    /**
+     * Accumulator
+     */
+    public int a;
+
+    /**
+     * X index regsiter
+     */
+    public int x;
+
+    /**
+     * Y index register
+     */
+    public int y;
+
+    /**
+     * Stack Pointer
+     */
+    public int sp;
+
+    /**
+     * Program Counter
+     */
+    public int pc;
+
+    /**
+     * Last Loaded Instruction Register
+     */
+    public int ir;
+
+    /**
+     * Peek-Ahead to next IR
+     */
+    public int nextIr;
+    public int[] args = new int[2];
+    public int[] nextArgs = new int[2];
+    public int instSize;
+    public boolean opTrap;
+    public boolean irqAsserted;
+    public boolean nmiAsserted;
+    public int lastPc;
+
+    /* Status Flag Register bits */
+    public boolean carryFlag;
+    public boolean negativeFlag;
+    public boolean zeroFlag;
+    public boolean irqDisableFlag;
+    public boolean decimalModeFlag;
+    public boolean breakFlag;
+    public boolean overflowFlag;
+    public long stepCounter = 0L;
+
+    public CpuState() {}
+
+    /**
+     * Snapshot a copy of the CpuState.
+     *
+     * (This is a copy constructor rather than an implementation of <code>Cloneable</code>
+     * based on Josh Bloch's recommendation)
+     *
+     * @param s The CpuState to copy.
+     */
+    public CpuState(CpuState s) {
+        this.a = s.a;
+        this.x = s.x;
+        this.y = s.y;
+        this.sp = s.sp;
+        this.pc = s.pc;
+        this.ir = s.ir;
+        this.nextIr = s.nextIr;
+        this.lastPc = s.lastPc;
+        this.args[0] = s.args[0];
+        this.args[1] = s.args[1];
+        this.nextArgs[0] = s.nextArgs[0];
+        this.nextArgs[1] = s.nextArgs[1];
+        this.instSize = s.instSize;
+        this.opTrap = s.opTrap;
+        this.irqAsserted = s.irqAsserted;
+        this.carryFlag = s.carryFlag;
+        this.negativeFlag = s.negativeFlag;
+        this.zeroFlag = s.zeroFlag;
+        this.irqDisableFlag = s.irqDisableFlag;
+        this.decimalModeFlag = s.decimalModeFlag;
+        this.breakFlag = s.breakFlag;
+        this.overflowFlag = s.overflowFlag;
+        this.stepCounter = s.stepCounter;
+    }
+
+    /**
+     * Returns a string formatted for the trace log.
+     *
+     * @return a string formatted for the trace log.
+     */
+    public String toTraceEvent() {
+        String opcode = Cpu.disassembleOp(ir, args);
+        return getInstructionByteStatus() + "  " +
+                String.format("%-14s", opcode) +
+                "A:" + Utils.byteToHex(a) + " " +
+                "X:" + Utils.byteToHex(x) + " " +
+                "Y:" + Utils.byteToHex(y) + " " +
+                "F:" + Utils.byteToHex(getStatusFlag()) + " " +
+                "S:1" + Utils.byteToHex(sp) + " " +
+                getProcessorStatusString() + "\n";
+    }
+
+    /**
+     * @return The value of the Process Status Register, as a byte.
+     */
+    public int getStatusFlag() {
+        int status = 0x20;
+        if (carryFlag) {
+            status |= Cpu.P_CARRY;
+        }
+        if (zeroFlag) {
+            status |= Cpu.P_ZERO;
+        }
+        if (irqDisableFlag) {
+            status |= Cpu.P_IRQ_DISABLE;
+        }
+        if (decimalModeFlag) {
+            status |= Cpu.P_DECIMAL;
+        }
+        if (breakFlag) {
+            status |= Cpu.P_BREAK;
+        }
+        if (overflowFlag) {
+            status |= Cpu.P_OVERFLOW;
+        }
+        if (negativeFlag) {
+            status |= Cpu.P_NEGATIVE;
+        }
+        return status;
+    }
+
+    public String getInstructionByteStatus() {
+        switch (Cpu.instructionSizes[ir]) {
+            case 0:
+            case 1:
+                return Utils.wordToHex(lastPc) + "  " +
+                       Utils.byteToHex(ir) + "      ";
+            case 2:
+                return Utils.wordToHex(lastPc) + "  " +
+                       Utils.byteToHex(ir) + " " +
+                       Utils.byteToHex(args[0]) + "   ";
+            case 3:
+                return Utils.wordToHex(lastPc) + "  " +
+                       Utils.byteToHex(ir) + " " +
+                       Utils.byteToHex(args[0]) + " " +
+                       Utils.byteToHex(args[1]);
+            default:
+                return null;
+        }
+    }
+
+    /**
+     * @return A string representing the current status register state.
+     */
+    public String getProcessorStatusString() {
+        return "[" + (negativeFlag ? 'N' : '.') +
+                (overflowFlag ? 'V' : '.') +
+                "-" +
+                (breakFlag ? 'B' : '.') +
+                (decimalModeFlag ? 'D' : '.') +
+                (irqDisableFlag ? 'I' : '.') +
+                (zeroFlag ? 'Z' : '.') +
+                (carryFlag ? 'C' : '.') +
+                "]";
+    }
+}
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008-2012 Seth J. Morabito <sethm@loomcom.com>
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
@@ -31,7 +31,7 @@ public interface InstructionTable {
     *
     * TODO: As of version 0.6, this is still not used! All CPUs are "idealized" NMOS 6502 only.
     */
-    public enum CpuBehavior {
+    enum CpuBehavior {
        /**
         * The earliest NMOS 6502 includes a bug that causes the ROR instruction
         * to behave like an ASL that does not affect the carry bit. This version
@@ -46,32 +46,33 @@ public interface InstructionTable {
         *
         * NB: Does NOT implement "unimplemented" NMOS instructions.
         */
-        NMOS_WITH_INDIRECT_JMP_BUG,
-
-        /**
-         * Emulate an NMOS 6502 without the indirect JMP bug. This type of 6502
-         * does not actually exist in the wild.
-         *
-         * NB: Does NOT implement "unimplemented" NMOS instructions.
-         */
-        NMOS_WITHOUT_INDIRECT_JMP_BUG,
+        NMOS_6502,

        /**
         * Emulate a CMOS 65C02, with all CMOS instructions and addressing modes.
         */
-        CMOS
+        CMOS_6502,
+
+        /**
+         * Emulate a CMOS 65C816.
+         */
+        CMOS_65816
    }

    /**
     * Enumeration of Addressing Modes.
     */
-    public enum Mode {
+    enum Mode {
        ACC {
            public String toString() {
                return "Accumulator";
            }
        },
-
+        AIX {
+            public String toString() {
+                return "Absolute, X-Indexed Indirect";
+            }
+        },
        ABS {
            public String toString() {
                return "Absolute";
@@ -128,19 +129,31 @@ public interface InstructionTable {

        ZPG {
            public String toString() {
-                return "Zeropage";
+                return "Zero Page";
+            }
+        },
+
+        ZPR {
+            public String toString() {
+                return "Zero Page, Relative";
            }
        },

        ZPX {
            public String toString() {
-                return "Zeropage, X-indexed";
+                return "Zero Page, X-indexed";
            }
        },

        ZPY {
            public String toString() {
-                return "Zeropage, Y-indexed";
+                return "Zero Page, Y-indexed";
+            }
+        },
+
+        ZPI {
+            public String toString() {
+                return "Zero Page Indirect";
            }
        },

@@ -154,156 +167,185 @@ public interface InstructionTable {
    // 6502 opcodes.  No 65C02 opcodes implemented.

    /**
-     * Instruction opcode names.
+     * Instruction opcode names. This lists all opcodes for
+     * NMOS 6502, CMOS 65C02, and CMOS 65C816
     */
-    public static final String[] opcodeNames = {
-        "BRK", "ORA",  null,  null,  null, "ORA", "ASL",  null,
-        "PHP", "ORA", "ASL",  null,  null, "ORA", "ASL",  null,
-        "BPL", "ORA",  null,  null,  null, "ORA", "ASL",  null,
-        "CLC", "ORA",  null,  null,  null, "ORA", "ASL",  null,
-        "JSR", "AND",  null,  null, "BIT", "AND", "ROL",  null,
-        "PLP", "AND", "ROL",  null, "BIT", "AND", "ROL",  null,
-        "BMI", "AND",  null,  null,  null, "AND", "ROL",  null,
-        "SEC", "AND",  null,  null,  null, "AND", "ROL",  null,
-        "RTI", "EOR",  null,  null,  null, "EOR", "LSR",  null,
-        "PHA", "EOR", "LSR",  null, "JMP", "EOR", "LSR",  null,
-        "BVC", "EOR",  null,  null,  null, "EOR", "LSR",  null,
-        "CLI", "EOR",  null,  null,  null, "EOR", "LSR",  null,
-        "RTS", "ADC",  null,  null,  null, "ADC", "ROR",  null,
-        "PLA", "ADC", "ROR",  null, "JMP", "ADC", "ROR",  null,
-        "BVS", "ADC",  null,  null,  null, "ADC", "ROR",  null,
-        "SEI", "ADC",  null,  null,  null, "ADC", "ROR",  null,
-        "BCS", "STA",  null,  null, "STY", "STA", "STX",  null,
-        "DEY",  null, "TXA",  null, "STY", "STA", "STX",  null,
-        "BCC", "STA",  null,  null, "STY", "STA", "STX",  null,
-        "TYA", "STA", "TXS",  null,  null, "STA",  null,  null,
-        "LDY", "LDA", "LDX",  null, "LDY", "LDA", "LDX",  null,
-        "TAY", "LDA", "TAX",  null, "LDY", "LDA", "LDX",  null,
-        "BCS", "LDA",  null,  null, "LDY", "LDA", "LDX",  null,
-        "CLV", "LDA", "TSX",  null, "LDY", "LDA", "LDX",  null,
-        "CPY", "CMP",  null,  null, "CPY", "CMP", "DEC",  null,
-        "INY", "CMP", "DEX",  null, "CPY", "CMP", "DEC",  null,
-        "BNE", "CMP",  null,  null,  null, "CMP", "DEC",  null,
-        "CLD", "CMP",  null,  null,  null, "CMP", "DEC",  null,
-        "CPX", "SBC",  null,  null, "CPX", "SBC", "INC",  null,
-        "INX", "SBC", "NOP",  null, "CPX", "SBC", "INC",  null,
-        "BEQ", "SBC",  null,  null,  null, "SBC", "INC",  null,
-        "SED", "SBC",  null,  null,  null, "SBC", "INC",  null
+    String[] opcodeNames = {
+        "BRK", "ORA", "NOP", "NOP", "TSB", "ORA", "ASL",  "RMB0",  // 0x00-0x07
+        "PHP", "ORA", "ASL", "NOP", "TSB", "ORA", "ASL",  "BBR0",  // 0x08-0x0f
+        "BPL", "ORA", "ORA", "NOP", "TRB", "ORA", "ASL",  "RMB1",  // 0x10-0x17
+        "CLC", "ORA", "INC", "NOP", "TRB", "ORA", "ASL",  "BBR1",  // 0x18-0x1f
+        "JSR", "AND", "NOP", "NOP", "BIT", "AND", "ROL",  "RMB2",  // 0x20-0x27
+        "PLP", "AND", "ROL", "NOP", "BIT", "AND", "ROL",  "BBR2",  // 0x28-0x2f
+        "BMI", "AND", "AND", "NOP", "BIT", "AND", "ROL",  "RMB3",  // 0x30-0x37
+        "SEC", "AND", "DEC", "NOP", "BIT", "AND", "ROL",  "BBR3",  // 0x38-0x3f
+        "RTI", "EOR", "NOP", "NOP", "NOP", "EOR", "LSR",  "RMB4",  // 0x40-0x47
+        "PHA", "EOR", "LSR", "NOP", "JMP", "EOR", "LSR",  "BBR4",  // 0x48-0x4f
+        "BVC", "EOR", "EOR", "NOP", "NOP", "EOR", "LSR",  "RMB5",  // 0x50-0x57
+        "CLI", "EOR", "PHY", "NOP", "NOP", "EOR", "LSR",  "BBR5",  // 0x58-0x5f
+        "RTS", "ADC", "NOP", "NOP", "STZ", "ADC", "ROR",  "RMB6",  // 0x60-0x67
+        "PLA", "ADC", "ROR", "NOP", "JMP", "ADC", "ROR",  "BBR6",  // 0x68-0x6f
+        "BVS", "ADC", "ADC", "NOP", "STZ", "ADC", "ROR",  "RMB7",  // 0x70-0x77
+        "SEI", "ADC", "PLY", "NOP", "JMP", "ADC", "ROR",  "BBR7",  // 0x78-0x7f
+        "BRA", "STA", "NOP", "NOP", "STY", "STA", "STX",  "SMB0",  // 0x80-0x87
+        "DEY", "BIT", "TXA", "NOP", "STY", "STA", "STX",  "BBS0",  // 0x88-0x8f
+        "BCC", "STA", "STA", "NOP", "STY", "STA", "STX",  "SMB1",  // 0x90-0x97
+        "TYA", "STA", "TXS", "NOP", "STZ", "STA", "STZ",  "BBS1",  // 0x98-0x9f
+        "LDY", "LDA", "LDX", "NOP", "LDY", "LDA", "LDX",  "SMB2",  // 0xa0-0xa7
+        "TAY", "LDA", "TAX", "NOP", "LDY", "LDA", "LDX",  "BBS2",  // 0xa8-0xaf
+        "BCS", "LDA", "LDA", "NOP", "LDY", "LDA", "LDX",  "SMB3",  // 0xb0-0xb7
+        "CLV", "LDA", "TSX", "NOP", "LDY", "LDA", "LDX",  "BBS3",  // 0xb8-0xbf
+        "CPY", "CMP", "NOP", "NOP", "CPY", "CMP", "DEC",  "SMB4",  // 0xc0-0xc7
+        "INY", "CMP", "DEX", "NOP", "CPY", "CMP", "DEC",  "BBS4",  // 0xc8-0xcf
+        "BNE", "CMP", "CMP", "NOP", "NOP", "CMP", "DEC",  "SMB5",  // 0xd0-0xd7
+        "CLD", "CMP", "PHX", "NOP", "NOP", "CMP", "DEC",  "BBS5",  // 0xd8-0xdf
+        "CPX", "SBC", "NOP", "NOP", "CPX", "SBC", "INC",  "SMB6",  // 0xe0-0xe7
+        "INX", "SBC", "NOP", "NOP", "CPX", "SBC", "INC",  "BBS6",  // 0xe8-0xef
+        "BEQ", "SBC", "SBC", "NOP", "NOP", "SBC", "INC",  "SMB7",  // 0xf0-0xf7
+        "SED", "SBC", "PLX", "NOP", "NOP", "SBC", "INC",  "BBS7"   // 0xf8-0xff
    };

    /**
-     * Instruction addressing modes.
+     * Instruction addressing modes. This table includes sizes
+     * for all instructions for NMOS 6502, CMOS 65C02,
+     * and CMOS 65C816
     */
-    public static final Mode[] instructionModes = {
+    Mode[] instructionModes = {
        Mode.IMP, Mode.XIN, Mode.NUL, Mode.NUL,   // 0x00-0x03
-        Mode.NUL, Mode.ZPG, Mode.ZPG, Mode.NUL,   // 0x04-0x07
+        Mode.ZPG, Mode.ZPG, Mode.ZPG, Mode.ZPG,   // 0x04-0x07
        Mode.IMP, Mode.IMM, Mode.ACC, Mode.NUL,   // 0x08-0x0b
-        Mode.NUL, Mode.ABS, Mode.ABS, Mode.NUL,   // 0x0c-0x0f
-        Mode.REL, Mode.INY, Mode.NUL, Mode.NUL,   // 0x10-0x13
-        Mode.NUL, Mode.ZPX, Mode.ZPX, Mode.NUL,   // 0x14-0x17
-        Mode.IMP, Mode.ABY, Mode.NUL, Mode.NUL,   // 0x18-0x1b
-        Mode.NUL, Mode.ABX, Mode.ABX, Mode.NUL,   // 0x1c-0x1f
+        Mode.ABS, Mode.ABS, Mode.ABS, Mode.ZPR,   // 0x0c-0x0f
+        Mode.REL, Mode.INY, Mode.ZPI, Mode.NUL,   // 0x10-0x13
+        Mode.ZPG, Mode.ZPX, Mode.ZPX, Mode.ZPG,   // 0x14-0x17
+        Mode.IMP, Mode.ABY, Mode.IMP, Mode.NUL,   // 0x18-0x1b
+        Mode.ABS, Mode.ABX, Mode.ABX, Mode.ZPR,   // 0x1c-0x1f
        Mode.ABS, Mode.XIN, Mode.NUL, Mode.NUL,   // 0x20-0x23
-        Mode.ZPG, Mode.ZPG, Mode.ZPG, Mode.NUL,   // 0x24-0x27
+        Mode.ZPG, Mode.ZPG, Mode.ZPG, Mode.ZPG,   // 0x24-0x27
        Mode.IMP, Mode.IMM, Mode.ACC, Mode.NUL,   // 0x28-0x2b
-        Mode.ABS, Mode.ABS, Mode.ABS, Mode.NUL,   // 0x2c-0x2f
-        Mode.REL, Mode.INY, Mode.NUL, Mode.NUL,   // 0x30-0x33
-        Mode.NUL, Mode.ZPX, Mode.ZPX, Mode.NUL,   // 0x34-0x37
-        Mode.IMP, Mode.ABY, Mode.NUL, Mode.NUL,   // 0x38-0x3b
-        Mode.NUL, Mode.ABX, Mode.ABX, Mode.NUL,   // 0x3c-0x3f
+        Mode.ABS, Mode.ABS, Mode.ABS, Mode.ZPR,   // 0x2c-0x2f
+        Mode.REL, Mode.INY, Mode.ZPI, Mode.NUL,   // 0x30-0x33
+        Mode.ZPX, Mode.ZPX, Mode.ZPX, Mode.ZPG,   // 0x34-0x37
+        Mode.IMP, Mode.ABY, Mode.IMP, Mode.NUL,   // 0x38-0x3b
+        Mode.NUL, Mode.ABX, Mode.ABX, Mode.ZPR,   // 0x3c-0x3f
        Mode.IMP, Mode.XIN, Mode.NUL, Mode.NUL,   // 0x40-0x43
-        Mode.NUL, Mode.ZPG, Mode.ZPG, Mode.NUL,   // 0x44-0x47
+        Mode.NUL, Mode.ZPG, Mode.ZPG, Mode.ZPG,   // 0x44-0x47
        Mode.IMP, Mode.IMM, Mode.ACC, Mode.NUL,   // 0x48-0x4b
-        Mode.ABS, Mode.ABS, Mode.ABS, Mode.NUL,   // 0x4c-0x4f
-        Mode.REL, Mode.INY, Mode.NUL, Mode.NUL,   // 0x50-0x53
-        Mode.NUL, Mode.ZPX, Mode.ZPX, Mode.NUL,   // 0x54-0x57
-        Mode.IMP, Mode.ABY, Mode.NUL, Mode.NUL,   // 0x58-0x5b
-        Mode.NUL, Mode.ABX, Mode.ABX, Mode.NUL,   // 0x5c-0x5f
+        Mode.ABS, Mode.ABS, Mode.ABS, Mode.ZPR,   // 0x4c-0x4f
+        Mode.REL, Mode.INY, Mode.ZPI, Mode.NUL,   // 0x50-0x53
+        Mode.NUL, Mode.ZPX, Mode.ZPX, Mode.ZPG,   // 0x54-0x57
+        Mode.IMP, Mode.ABY, Mode.IMP, Mode.NUL,   // 0x58-0x5b
+        Mode.NUL, Mode.ABX, Mode.ABX, Mode.ZPR,   // 0x5c-0x5f
        Mode.IMP, Mode.XIN, Mode.NUL, Mode.NUL,   // 0x60-0x63
-        Mode.NUL, Mode.ZPG, Mode.ZPG, Mode.NUL,   // 0x64-0x67
+        Mode.ZPG, Mode.ZPG, Mode.ZPG, Mode.ZPG,   // 0x64-0x67
        Mode.IMP, Mode.IMM, Mode.ACC, Mode.NUL,   // 0x68-0x6b
-        Mode.IND, Mode.ABS, Mode.ABS, Mode.NUL,   // 0x6c-0x6f
-        Mode.REL, Mode.INY, Mode.NUL, Mode.NUL,   // 0x70-0x73
-        Mode.NUL, Mode.ZPX, Mode.ZPX, Mode.NUL,   // 0x74-0x77
-        Mode.IMP, Mode.ABY, Mode.NUL, Mode.NUL,   // 0x78-0x7b
-        Mode.NUL, Mode.ABX, Mode.ABX, Mode.NUL,   // 0x7c-0x7f
+        Mode.IND, Mode.ABS, Mode.ABS, Mode.ZPR,   // 0x6c-0x6f
+        Mode.REL, Mode.INY, Mode.ZPI, Mode.NUL,   // 0x70-0x73
+        Mode.ZPX, Mode.ZPX, Mode.ZPX, Mode.ZPG,   // 0x74-0x77
+        Mode.IMP, Mode.ABY, Mode.IMP, Mode.NUL,   // 0x78-0x7b
+        Mode.AIX, Mode.ABX, Mode.ABX, Mode.ZPR,   // 0x7c-0x7f
        Mode.REL, Mode.XIN, Mode.NUL, Mode.NUL,   // 0x80-0x83
-        Mode.ZPG, Mode.ZPG, Mode.ZPG, Mode.NUL,   // 0x84-0x87
-        Mode.IMP, Mode.NUL, Mode.IMP, Mode.NUL,   // 0x88-0x8b
-        Mode.ABS, Mode.ABS, Mode.ABS, Mode.NUL,   // 0x8c-0x8f
-        Mode.REL, Mode.INY, Mode.NUL, Mode.NUL,   // 0x90-0x93
-        Mode.ZPX, Mode.ZPX, Mode.ZPY, Mode.NUL,   // 0x94-0x97
+        Mode.ZPG, Mode.ZPG, Mode.ZPG, Mode.ZPG,   // 0x84-0x87
+        Mode.IMP, Mode.IMM, Mode.IMP, Mode.NUL,   // 0x88-0x8b
+        Mode.ABS, Mode.ABS, Mode.ABS, Mode.ZPR,   // 0x8c-0x8f
+        Mode.REL, Mode.INY, Mode.ZPI, Mode.NUL,   // 0x90-0x93
+        Mode.ZPX, Mode.ZPX, Mode.ZPY, Mode.ZPG,   // 0x94-0x97
        Mode.IMP, Mode.ABY, Mode.IMP, Mode.NUL,   // 0x98-0x9b
-        Mode.NUL, Mode.ABX, Mode.NUL, Mode.NUL,   // 0x9c-0x9f
+        Mode.ABS, Mode.ABX, Mode.ABX, Mode.ZPR,   // 0x9c-0x9f
        Mode.IMM, Mode.XIN, Mode.IMM, Mode.NUL,   // 0xa0-0xa3
-        Mode.ZPG, Mode.ZPG, Mode.ZPG, Mode.NUL,   // 0xa4-0xa7
+        Mode.ZPG, Mode.ZPG, Mode.ZPG, Mode.ZPG,   // 0xa4-0xa7
        Mode.IMP, Mode.IMM, Mode.IMP, Mode.NUL,   // 0xa8-0xab
-        Mode.ABS, Mode.ABS, Mode.ABS, Mode.NUL,   // 0xac-0xaf
-        Mode.REL, Mode.INY, Mode.NUL, Mode.NUL,   // 0xb0-0xb3
-        Mode.ZPX, Mode.ZPX, Mode.ZPY, Mode.NUL,   // 0xb4-0xb7
+        Mode.ABS, Mode.ABS, Mode.ABS, Mode.ZPR,   // 0xac-0xaf
+        Mode.REL, Mode.INY, Mode.ZPI, Mode.NUL,   // 0xb0-0xb3
+        Mode.ZPX, Mode.ZPX, Mode.ZPY, Mode.ZPG,   // 0xb4-0xb7
        Mode.IMP, Mode.ABY, Mode.IMP, Mode.NUL,   // 0xb8-0xbb
-        Mode.ABX, Mode.ABX, Mode.ABY, Mode.NUL,   // 0xbc-0xbf
+        Mode.ABX, Mode.ABX, Mode.ABY, Mode.ZPR,   // 0xbc-0xbf
        Mode.IMM, Mode.XIN, Mode.NUL, Mode.NUL,   // 0xc0-0xc3
-        Mode.ZPG, Mode.ZPG, Mode.ZPG, Mode.NUL,   // 0xc4-0xc7
+        Mode.ZPG, Mode.ZPG, Mode.ZPG, Mode.ZPG,   // 0xc4-0xc7
        Mode.IMP, Mode.IMM, Mode.IMP, Mode.NUL,   // 0xc8-0xcb
-        Mode.ABS, Mode.ABS, Mode.ABS, Mode.NUL,   // 0xcc-0xcf
-        Mode.REL, Mode.INY, Mode.NUL, Mode.NUL,   // 0xd0-0xd3
-        Mode.NUL, Mode.ZPX, Mode.ZPX, Mode.NUL,   // 0xd4-0xd7
-        Mode.IMP, Mode.ABY, Mode.NUL, Mode.NUL,   // 0xd8-0xdb
-        Mode.NUL, Mode.ABX, Mode.ABX, Mode.NUL,   // 0xdc-0xdf
+        Mode.ABS, Mode.ABS, Mode.ABS, Mode.ZPR,   // 0xcc-0xcf
+        Mode.REL, Mode.INY, Mode.ZPI, Mode.NUL,   // 0xd0-0xd3
+        Mode.NUL, Mode.ZPX, Mode.ZPX, Mode.ZPG,   // 0xd4-0xd7
+        Mode.IMP, Mode.ABY, Mode.IMP, Mode.NUL,   // 0xd8-0xdb
+        Mode.NUL, Mode.ABX, Mode.ABX, Mode.ZPR,   // 0xdc-0xdf
        Mode.IMM, Mode.XIN, Mode.NUL, Mode.NUL,   // 0xe0-0xe3
-        Mode.ZPG, Mode.ZPG, Mode.ZPG, Mode.NUL,   // 0xe4-0xe7
+        Mode.ZPG, Mode.ZPG, Mode.ZPG, Mode.ZPG,   // 0xe4-0xe7
        Mode.IMP, Mode.IMM, Mode.IMP, Mode.NUL,   // 0xe8-0xeb
-        Mode.ABS, Mode.ABS, Mode.ABS, Mode.NUL,   // 0xec-0xef
-        Mode.REL, Mode.INY, Mode.NUL, Mode.NUL,   // 0xf0-0xf3
-        Mode.NUL, Mode.ZPX, Mode.ZPX, Mode.NUL,   // 0xf4-0xf7
-        Mode.IMP, Mode.ABY, Mode.NUL, Mode.NUL,   // 0xf8-0xfb
-        Mode.NUL, Mode.ABX, Mode.ABX, Mode.NUL    // 0xfc-0xff
+        Mode.ABS, Mode.ABS, Mode.ABS, Mode.ZPR,   // 0xec-0xef
+        Mode.REL, Mode.INY, Mode.ZPI, Mode.NUL,   // 0xf0-0xf3
+        Mode.NUL, Mode.ZPX, Mode.ZPX, Mode.ZPG,   // 0xf4-0xf7
+        Mode.IMP, Mode.ABY, Mode.IMP, Mode.NUL,   // 0xf8-0xfb
+        Mode.NUL, Mode.ABX, Mode.ABX, Mode.ZPR    // 0xfc-0xff
    };


    /**
-     * Size, in bytes, required for each instruction.
+     * Size, in bytes, required for each instruction. This table
+     * includes sizes for all instructions for NMOS 6502, CMOS 65C02,
+     * and CMOS 65C816
     */
-    public static final int[] instructionSizes = {
-        1, 2, 0, 0, 0, 2, 2, 0, 1, 2, 1, 0, 0, 3, 3, 0,
-        2, 2, 0, 0, 0, 2, 2, 0, 1, 3, 0, 0, 0, 3, 3, 0,
-        3, 2, 0, 0, 2, 2, 2, 0, 1, 2, 1, 0, 3, 3, 3, 0,
-        2, 2, 0, 0, 0, 2, 2, 0, 1, 3, 0, 0, 0, 3, 3, 0,
-        1, 2, 0, 0, 0, 2, 2, 0, 1, 2, 1, 0, 3, 3, 3, 0,
-        2, 2, 0, 0, 0, 2, 2, 0, 1, 3, 0, 0, 0, 3, 3, 0,
-        1, 2, 0, 0, 0, 2, 2, 0, 1, 2, 1, 0, 3, 3, 3, 0,
-        2, 2, 0, 0, 0, 2, 2, 0, 1, 3, 0, 0, 0, 3, 3, 0,
-        2, 2, 0, 0, 2, 2, 2, 0, 1, 0, 1, 0, 3, 3, 3, 0,
-        2, 2, 0, 0, 2, 2, 2, 0, 1, 3, 1, 0, 0, 3, 0, 0,
-        2, 2, 2, 0, 2, 2, 2, 0, 1, 2, 1, 0, 3, 3, 3, 0,
-        2, 2, 0, 0, 2, 2, 2, 0, 1, 3, 1, 0, 3, 3, 3, 0,
-        2, 2, 0, 0, 2, 2, 2, 0, 1, 2, 1, 0, 3, 3, 3, 0,
-        2, 2, 0, 0, 0, 2, 2, 0, 1, 3, 0, 0, 0, 3, 3, 0,
-        2, 2, 0, 0, 2, 2, 2, 0, 1, 2, 1, 0, 3, 3, 3, 0,
-        2, 2, 0, 0, 0, 2, 2, 0, 1, 3, 0, 0, 0, 3, 3, 0
+    int[] instructionSizes = {
+        1, 2, 2, 1, 2, 2, 2, 2, 1, 2, 1, 1, 3, 3, 3, 3,   // 0x00-0x0f
+        2, 2, 2, 1, 2, 2, 2, 2, 1, 3, 1, 1, 3, 3, 3, 3,   // 0x10-0x1f
+        3, 2, 2, 1, 2, 2, 2, 2, 1, 2, 1, 1, 3, 3, 3, 3,   // 0x20-0x2f
+        2, 2, 2, 1, 2, 2, 2, 2, 1, 3, 1, 1, 3, 3, 3, 3,   // 0x30-0x3f
+        1, 2, 2, 1, 2, 2, 2, 2, 1, 2, 1, 1, 3, 3, 3, 3,   // 0x40-0x4f
+        2, 2, 2, 1, 2, 2, 2, 2, 1, 3, 1, 1, 3, 3, 3, 3,   // 0x50-0x5f
+        1, 2, 2, 1, 2, 2, 2, 2, 1, 2, 1, 1, 3, 3, 3, 3,   // 0x60-0x6f
+        2, 2, 2, 1, 2, 2, 2, 2, 1, 3, 1, 1, 3, 3, 3, 3,   // 0x70-0x7f
+        2, 2, 2, 1, 2, 2, 2, 2, 1, 2, 1, 1, 3, 3, 3, 3,   // 0x80-0x8f
+        2, 2, 2, 1, 2, 2, 2, 2, 1, 3, 1, 1, 3, 3, 3, 3,   // 0x90-0x9f
+        2, 2, 2, 1, 2, 2, 2, 2, 1, 2, 1, 1, 3, 3, 3, 3,   // 0xa0-0xaf
+        2, 2, 2, 1, 2, 2, 2, 2, 1, 3, 1, 1, 3, 3, 3, 3,   // 0xb0-0xbf
+        2, 2, 2, 1, 2, 2, 2, 2, 1, 2, 1, 1, 3, 3, 3, 3,   // 0xc0-0xcf
+        2, 2, 2, 1, 2, 2, 2, 2, 1, 3, 1, 1, 3, 3, 3, 3,   // 0xd0-0xdf
+        2, 2, 2, 1, 2, 2, 2, 2, 1, 2, 1, 1, 3, 3, 3, 3,   // 0xe0-0xef
+        2, 2, 2, 1, 2, 2, 2, 2, 1, 3, 1, 1, 3, 3, 3, 3    // 0xf0-0xff
    };

    /**
-     * Number of clock cycles required for each instruction
+     * Number of clock cycles required for each instruction when
+     * in NMOS mode.
     */
-    public static final int[] instructionClocks = {
-        7, 6, 0, 0, 0, 3, 5, 0, 3, 2, 2, 0, 0, 4, 6, 0,
-        2, 5, 0, 0, 0, 4, 6, 0, 2, 4, 0, 0, 0, 4, 7, 0,
-        6, 6, 0, 0, 3, 3, 5, 0, 4, 2, 2, 0, 4, 4, 6, 0,
-        2, 5, 0, 0, 0, 4, 6, 0, 2, 4, 0, 0, 0, 4, 7, 0,
-        6, 6, 0, 0, 0, 3, 5, 0, 3, 2, 2, 0, 3, 4, 6, 0,
-        2, 5, 0, 0, 0, 4, 6, 0, 2, 4, 0, 0, 0, 4, 7, 0,
-        6, 6, 0, 0, 0, 3, 5, 0, 4, 2, 2, 0, 5, 4, 6, 0,
-        2, 5, 0, 0, 0, 4, 6, 0, 2, 4, 0, 0, 0, 4, 7, 0,
-        2, 6, 0, 0, 3, 3, 3, 0, 2, 0, 2, 0, 4, 4, 4, 0,
-        2, 6, 0, 0, 4, 4, 4, 0, 2, 5, 2, 0, 0, 5, 0, 0,
-        2, 6, 2, 0, 3, 3, 3, 0, 2, 2, 2, 0, 4, 4, 4, 0,
-        2, 5, 0, 0, 4, 4, 4, 0, 2, 4, 2, 0, 4, 4, 4, 0,
-        2, 6, 0, 0, 3, 3, 5, 0, 2, 2, 2, 0, 4, 4, 6, 0,
-        2, 5, 0, 0, 0, 4, 6, 0, 2, 4, 0, 0, 0, 4, 7, 0,
-        2, 6, 0, 0, 3, 3, 5, 0, 2, 2, 2, 0, 4, 4, 6, 0,
-        2, 5, 0, 0, 0, 4, 6, 0, 2, 4, 0, 0, 0, 4, 7, 0
+    int[] instructionClocksNmos = {
+        7, 6, 1, 8, 3, 3, 5, 5, 3, 2, 2, 2, 4, 4, 6, 6,   // 0x00-0x0f
+        2, 5, 1, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7,   // 0x10-0x1f
+        6, 6, 1, 8, 3, 3, 5, 5, 4, 2, 2, 2, 4, 4, 6, 6,   // 0x20-0x2f
+        2, 5, 1, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7,   // 0x30-0x3f
+        6, 6, 1, 8, 3, 3, 5, 5, 3, 2, 2, 2, 3, 4, 6, 6,   // 0x40-0x4f
+        2, 5, 1, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7,   // 0x50-0x5f
+        6, 6, 1, 8, 3, 3, 5, 5, 4, 2, 2, 2, 5, 4, 6, 6,   // 0x60-0x6f
+        2, 5, 1, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7,   // 0x70-0x7f
+        2, 6, 2, 6, 3, 3, 3, 3, 2, 2, 2, 2, 4, 4, 4, 4,   // 0x80-0x8f
+        2, 6, 1, 6, 4, 4, 4, 4, 2, 5, 2, 5, 5, 5, 5, 5,   // 0x90-0x9f
+        2, 6, 2, 6, 3, 3, 3, 3, 2, 2, 2, 2, 4, 4, 4, 4,   // 0xa0-0xaf
+        2, 5, 1, 5, 4, 4, 4, 4, 2, 4, 2, 4, 4, 4, 4, 4,   // 0xb0-0xbf
+        2, 6, 2, 8, 3, 3, 5, 5, 2, 2, 2, 2, 4, 4, 6, 6,   // 0xc0-0xcf
+        2, 5, 1, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7,   // 0xd0-0xdf
+        2, 6, 2, 8, 3, 3, 5, 5, 2, 2, 2, 2, 4, 4, 6, 6,   // 0xe0-0xef
+        2, 5, 1, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7    // 0xf0-0xff
+    };
+
+    /**
+     * Number of clock cycles required for each instruction when
+     * in CMOS mode
+     */
+    int[] instructionClocksCmos = {
+        7, 6, 2, 1, 5, 3, 5, 5, 3, 2, 2, 1, 6, 4, 6, 5,   // 0x00-0x0f
+        2, 5, 5, 1, 5, 4, 6, 5, 2, 4, 2, 1, 6, 4, 6, 5,   // 0x10-0x1f
+        6, 6, 2, 1, 3, 3, 5, 5, 4, 2, 2, 1, 4, 4, 6, 5,   // 0x20-0x2f
+        2, 5, 5, 1, 4, 4, 6, 5, 2, 4, 2, 1, 4, 4, 6, 5,   // 0x30-0x3f
+        6, 6, 2, 1, 2, 3, 5, 3, 3, 2, 2, 1, 3, 4, 6, 5,   // 0x40-0x4f
+        2, 5, 5, 1, 4, 4, 6, 5, 2, 4, 3, 1, 8, 4, 6, 5,   // 0x50-0x5f
+        6, 6, 2, 1, 3, 3, 5, 5, 4, 2, 2, 1, 6, 4, 6, 5,   // 0x60-0x6f
+        2, 5, 5, 1, 4, 4, 6, 5, 2, 4, 4, 3, 6, 4, 6, 5,   // 0x70-0x7f
+        3, 6, 2, 1, 3, 3, 3, 5, 2, 2, 2, 1, 4, 4, 4, 5,   // 0x80-0x8f
+        2, 6, 5, 1, 4, 4, 4, 5, 2, 5, 2, 1, 4, 5, 5, 5,   // 0x90-0x9f
+        2, 6, 2, 1, 3, 3, 3, 5, 2, 2, 2, 1, 4, 4, 4, 5,   // 0xa0-0xaf
+        2, 5, 5, 1, 4, 4, 4, 5, 2, 4, 2, 1, 4, 4, 4, 5,   // 0xb0-0xbf
+        2, 6, 2, 1, 3, 3, 5, 5, 2, 2, 2, 3, 4, 4, 6, 5,   // 0xc0-0xcf
+        2, 5, 5, 1, 4, 4, 6, 5, 2, 4, 3, 3, 4, 4, 7, 5,   // 0xd0-0xdf
+        2, 6, 2, 1, 3, 3, 5, 5, 2, 2, 2, 1, 4, 4, 6, 5,   // 0xe0-0xef
+        2, 5, 5, 1, 4, 4, 6, 5, 2, 4, 4, 1, 4, 4, 7, 5    // 0xf0-0xff
    };

 }
@@ -0,0 +1,157 @@
+/*
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
+ *                    Maik Merten <maikmerten@googlemail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+
+package com.loomcom.symon;
+
+import com.loomcom.symon.machines.MulticompMachine;
+import com.loomcom.symon.machines.SimpleMachine;
+import com.loomcom.symon.machines.SymonMachine;
+import org.apache.commons.cli.*;
+
+import java.util.Locale;
+import javax.swing.JOptionPane;
+import javax.swing.SwingUtilities;
+import javax.swing.UIManager;
+
+public class Main {
+    
+     /**
+     * Main entry point to the simulator. Creates a simulator and shows the main
+     * window.
+     *
+     * @param args Program arguments
+     */
+    public static void main(String[] args) throws Exception {
+        
+        Class machineClass = SymonMachine.class;
+
+        Options options = new Options();
+
+        options.addOption(new Option("m", "machine", true, "Specify machine type."));
+        options.addOption(new Option("c", "cpu", true, "Specify CPU type."));
+        options.addOption(new Option("r", "rom", true, "Specify ROM file."));
+
+        CommandLineParser parser = new DefaultParser();
+
+        try {
+            CommandLine line = parser.parse(options, args);
+            InstructionTable.CpuBehavior cpuBehavior = null;
+            String romFile = null;
+
+            if (line.hasOption("machine")) {
+                String machine = line.getOptionValue("machine").toLowerCase(Locale.ENGLISH);
+                switch (machine) {
+                    case "multicomp":
+                        machineClass = MulticompMachine.class;
+                        break;
+                    case "simple":
+                        machineClass = SimpleMachine.class;
+                        break;
+                    case "symon":
+                        machineClass = SymonMachine.class;
+                        break;
+                    default:
+                        System.err.println("Could not start Symon. Unknown machine type " + machine);
+                        return;
+                }
+            }
+
+            if (line.hasOption("cpu")) {
+                String cpu = line.getOptionValue("cpu").toLowerCase(Locale.ENGLISH);
+                switch (cpu) {
+                    case "6502":
+                        cpuBehavior = InstructionTable.CpuBehavior.NMOS_6502;
+                        break;
+                    case "65c02":
+                        cpuBehavior = InstructionTable.CpuBehavior.CMOS_6502;
+                        break;
+                    case "65c816":
+                        cpuBehavior = InstructionTable.CpuBehavior.CMOS_65816;
+                        break;
+                    default:
+                        System.err.println("Could not start Symon. Unknown cpu type " + cpu);
+                        return;
+                }
+            }
+
+            if (line.hasOption("rom")) {
+                romFile = line.getOptionValue("rom");
+            }
+
+            while (true) {
+                if (machineClass == null) {
+                    Object[] possibilities = {"Symon", "Multicomp", "Simple"};
+                    String s = (String)JOptionPane.showInputDialog(
+                            null,
+                            "Please choose the machine type to be emulated:",
+                            "Machine selection",
+                            JOptionPane.PLAIN_MESSAGE,
+                            null,
+                            possibilities,
+                            "Symon");
+
+
+                    if (s != null && s.equals("Multicomp")) {
+                        machineClass = MulticompMachine.class;
+                    } else if (s != null && s.equals("Simple")) {
+                        machineClass = SimpleMachine.class;
+                    } else {
+                        machineClass = SymonMachine.class;
+                    }
+                }
+
+                if (cpuBehavior == null) {
+                    cpuBehavior = InstructionTable.CpuBehavior.NMOS_6502;
+                }
+
+                final Simulator simulator = new Simulator(machineClass, cpuBehavior, romFile);
+
+                SwingUtilities.invokeLater(new Runnable() {
+                    @Override
+                    public void run() {
+                        try {
+                            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
+                            // Create the main UI window
+                            simulator.createAndShowUi();
+                        } catch (Exception e) {
+                            e.printStackTrace();
+                        }
+                    }
+                });
+
+
+                Simulator.MainCommand cmd = simulator.waitForCommand();
+
+                if (cmd.equals(Simulator.MainCommand.SELECTMACHINE)) {
+                    machineClass = null;
+                } else {
+                    break;
+                }
+            }
+        } catch (ParseException ex) {
+            System.err.println("Could not start Symon. Reason: " + ex.getMessage());
+        }
+    }
+}
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008-2013 Seth J. Morabito <sethm@loomcom.com>
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
@@ -34,77 +34,78 @@ import com.loomcom.symon.exceptions.*;
 */
 public class MemoryRange implements Comparable<MemoryRange> {

-  /** The starting address of the memory range. */
-  public int startAddress;
-  /** The ending address of the memory range. */
-  public int endAddress;
+    /**
+     * The starting address of the memory range.
+     */
+    public int startAddress;
+    /**
+     * The ending address of the memory range.
+     */
+    public int endAddress;

-  public MemoryRange(int startAddress, int endAddress)
-		throws MemoryRangeException {
-    if (startAddress < 0 || endAddress < 0) {
-      throw new MemoryRangeException("Addresses cannot be less than 0.");
+    public MemoryRange(int startAddress, int endAddress)
+            throws MemoryRangeException {
+        if (startAddress < 0 || endAddress < 0) {
+            throw new MemoryRangeException("Addresses cannot be less than 0.");
+        }
+        if (startAddress >= endAddress) {
+            throw new MemoryRangeException("End address must be greater " +
+                    "than start address.");
+        }
+        this.startAddress = startAddress;
+        this.endAddress = endAddress;
    }
-    if (startAddress >= endAddress) {
-      throw new MemoryRangeException("End address must be greater " +
-                                     "than start address.");
+
+    /**
+     * @return the starting address.
+     */
+    public int startAddress() {
+        return startAddress;
    }
-    this.startAddress = startAddress;
-    this.endAddress = endAddress;
-  }

-  /**
-   * @returns the starting address.
-   */
-  public int startAddress() {
-    return startAddress;
-  }
-
-  /**
-   * @returns the ending address.
-   */
-  public int endAddress() {
-    return endAddress;
-  }
-
-  /**
-   * Checks for address inclusion in the range.
-   *
-   * @returns true if the address is included within this range,
-   *          false otherwise.
-   */
-  public boolean includes(int address) {
-    return (address <= endAddress &&
-            address >= startAddress);
-  }
-
-  /**
-   * Checks for overlapping memory ranges.
-   *
-   * @returns true if this range overlaps in any way with the other.
-   */
-  public boolean overlaps(MemoryRange other) {
-    return (this.includes(other.startAddress()) ||
-            other.includes(this.startAddress()));
-  }
-
-  // Implementation of Comparable interface
-  public int compareTo(MemoryRange other) {
-    if (other == null) {
-      throw new NullPointerException("Cannot compare to null.");
+    /**
+     * @return the ending address.
+     */
+    public int endAddress() {
+        return endAddress;
    }
-    if (this == other) {
-      return 0;
-    }
-    Integer thisStartAddr = new Integer(this.startAddress());
-    Integer thatStartAddr = new Integer(other.startAddress());
-    return thisStartAddr.compareTo(thatStartAddr);
-  }

-  public String toString() {
-    StringBuffer desc = new StringBuffer("@");
-    desc.append(String.format("0x%04x", startAddress));
-    desc.append("-");
-    desc.append(String.format("0x%04x", endAddress));
-    return desc.toString();
-  }
+    /**
+     * Checks for address inclusion in the range.
+     *
+     * @return true if the address is included within this range,
+     * false otherwise.
+     */
+    public boolean includes(int address) {
+        return (address <= endAddress &&
+                address >= startAddress);
+    }
+
+    /**
+     * Checks for overlapping memory ranges.
+     *
+     * @return true if this range overlaps in any way with the other.
+     */
+    public boolean overlaps(MemoryRange other) {
+        return (this.includes(other.startAddress()) ||
+                other.includes(this.startAddress()));
+    }
+
+    // Implementation of Comparable interface
+    public int compareTo(MemoryRange other) {
+        if (other == null) {
+            throw new NullPointerException("Cannot compare to null.");
+        }
+        if (this == other) {
+            return 0;
+        }
+        Integer thisStartAddr = this.startAddress();
+        Integer thatStartAddr = other.startAddress();
+        return thisStartAddr.compareTo(thatStartAddr);
+    }
+
+    public String toString() {
+        return "@" + String.format("0x%04x", startAddress) + "-" +
+                String.format("0x%04x", endAddress);
+    }
 }
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008-2013 Seth J. Morabito <sethm@loomcom.com>
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
@@ -27,15 +27,15 @@ import javax.swing.*;

 public interface Preferences {

-    public static final int DEFAULT_PROGRAM_LOAD_ADDRESS = 0x0300;
+    int DEFAULT_PROGRAM_LOAD_ADDRESS = 0x0300;

-    public static final boolean DEFAULT_HALT_ON_BREAK = true;
+    boolean DEFAULT_HALT_ON_BREAK = true;

-    public JDialog getDialog();
+    JDialog getDialog();

-    public int getProgramStartAddress();
+    int getProgramStartAddress();

-    public boolean getHaltOnBreak();
+    boolean getHaltOnBreak();

-    public void updateUi();
+    void updateUi();
 }
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008-2013 Seth J. Morabito <sethm@loomcom.com>
+ * Copyrighi (c) 2016 Seth J. Morabito <web@loomcom.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
@@ -23,24 +23,22 @@

 package com.loomcom.symon;

-import com.loomcom.symon.devices.Acia;
-import com.loomcom.symon.devices.Crtc;
 import com.loomcom.symon.devices.Memory;
-import com.loomcom.symon.devices.Via;
-import com.loomcom.symon.exceptions.FifoUnderrunException;
-import com.loomcom.symon.exceptions.MemoryAccessException;
-import com.loomcom.symon.exceptions.MemoryRangeException;
-import com.loomcom.symon.exceptions.SymonException;
+import com.loomcom.symon.exceptions.*;
+import com.loomcom.symon.machines.Machine;
 import com.loomcom.symon.ui.*;
 import com.loomcom.symon.ui.Console;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;

+import javax.management.monitor.CounterMonitor;
 import javax.swing.*;
 import javax.swing.border.EmptyBorder;
 import java.awt.*;
 import java.awt.event.*;
 import java.io.*;
-import java.util.logging.Level;
-import java.util.logging.Logger;
+import java.util.SortedSet;
+import java.util.TreeSet;

 /**
 * Symon Simulator Interface and Control.
@@ -52,59 +50,33 @@ import java.util.logging.Logger;
 */
 public class Simulator {

-    // Constants used by the simulated system. These define the memory map.
-    private static final int BUS_BOTTOM = 0x0000;
-    private static final int BUS_TOP    = 0xffff;
-
-    // 32K of RAM from $0000 - $7FFF
-    private static final int MEMORY_BASE = 0x0000;
-    private static final int MEMORY_SIZE = 0x8000;
-
-    // VIA at $8000-$800F
-
-    private static final int VIA_BASE = 0x8000;
-
-    // ACIA at $8800-$8803
-    private static final int ACIA_BASE = 0x8800;
-
-    // CRTC at $9000-$9001
-    private static final int CRTC_BASE = 0x9000;
-    private static final int VIDEO_RAM_BASE = 0x7000;
-
-    // 16KB ROM at $C000-$FFFF
-    private static final int ROM_BASE = 0xC000;
-    private static final int ROM_SIZE = 0x4000;
+    private final static Logger logger = LoggerFactory.getLogger(Simulator.class.getName());

    // UI constants
-    private static final int  DEFAULT_FONT_SIZE    = 12;
-    private static final Font DEFAULT_FONT         = new Font(Font.MONOSPACED, Font.PLAIN, DEFAULT_FONT_SIZE);
-    private static final int  CONSOLE_BORDER_WIDTH = 10;
+    private static final int DEFAULT_FONT_SIZE = 12;
+    private static final Font DEFAULT_FONT = new Font(Font.MONOSPACED, Font.PLAIN, DEFAULT_FONT_SIZE);
+    private static final int CONSOLE_BORDER_WIDTH = 10;
+
+    // Clock periods, in NS, for each speed. 0MHz, 1MHz, 2MHz, 3MHz, 4MHz, 5MHz, 6MHz, 7MHz, 8MHz.
+    private static final long[] CLOCK_PERIODS = {0, 1000, 500, 333, 250, 200, 167, 143, 125};

    // Since it is very expensive to update the UI with Swing's Event Dispatch Thread, we can't afford
    // to refresh the status view on every simulated clock cycle. Instead, we will only refresh the status view
    // after this number of steps when running normally.
    //
-    // Since we're simulating a 1MHz 6502 here, we have a 1 us delay between steps. Setting this to 10000
-    // should give us a status update every 10 ms.
+    // Since we're simulating a 1MHz 6502 here, we have a 1 us delay between steps. Setting this to 20000
+    // should give us a status update about every 100 ms.
    //
    // TODO: Work around the event dispatch thread with custom painting code instead of relying on Swing.
    //
-    private static final int MAX_STEPS_BETWEEN_UPDATES = 10000;
+    private static final int MAX_STEPS_BETWEEN_UPDATES = 20000;

-    private final static Logger logger = Logger.getLogger(Simulator.class.getName());
-
-    // The simulated peripherals
-    private final Bus    bus;
-    private final Cpu    cpu;
-    private final Acia   acia;
-    private final Via    via;
-    private final Crtc   crtc;
-    private final Memory ram;
-    private       Memory rom;
+    // The simulated machine
+    private Machine machine;

    // Number of CPU steps between CRT repaints.
    // TODO: Dynamically refresh the value at runtime based on performance figures to reach ~ 30fps.
-    private long stepsBetweenCrtcRefreshes = 2500;
+    private static final long STEPS_BETWEEN_CRTC_REFRESHES = 2500;

    // A counter to keep track of the number of UI updates that have been
    // requested
@@ -124,61 +96,67 @@ public class Simulator {
    /**
     * The Trace Window shows the most recent 50,000 CPU states.
     */
-    private TraceLog traceLog;
+    private final TraceLog traceLog;

    /**
     * The Memory Window shows the contents of one page of memory.
     */
-    private MemoryWindow memoryWindow;
+    private final MemoryWindow memoryWindow;

-    private VideoWindow videoWindow;
+    private final VideoWindow videoWindow;
+
+    private final BreakpointsWindow breakpointsWindow;

    private SimulatorMenu menuBar;

-    private RunLoop     runLoop;
-    private Console     console;
+    private RunLoop runLoop;
+    private Console console;
    private StatusPanel statusPane;

    private JButton runStopButton;
    private JButton stepButton;
-    private JButton resetButton;
-    private JComboBox stepCountBox;
+    private JComboBox<String> stepCountBox;

-    private JFileChooser      fileChooser;
+    private JFileChooser fileChooser;
    private PreferencesDialog preferences;

+    private Breakpoints breakpoints;
+
+    private final Object commandMonitorObject = new Object();
+
+    private MainCommand command = MainCommand.NONE;
+
+    public enum MainCommand {
+        NONE,
+        SELECTMACHINE
+    }
+
    /**
     * The list of step counts that will appear in the "Step" drop-down.
     */
    private static final String[] STEPS = {"1", "5", "10", "20", "50", "100"};

-    public Simulator() throws MemoryRangeException, IOException {
-        this.bus = new Bus(BUS_BOTTOM, BUS_TOP);
-        this.cpu = new Cpu();
-        this.ram = new Memory(MEMORY_BASE, MEMORY_BASE + MEMORY_SIZE - 1, false);
-        this.via = new Via(VIA_BASE);
-        this.acia = new Acia(ACIA_BASE);
-        this.crtc = new Crtc(CRTC_BASE, ram);
+    public Simulator(Class machineClass) throws Exception {
+        this(machineClass, InstructionTable.CpuBehavior.NMOS_6502, null);
+    }

-        bus.addCpu(cpu);
+    public Simulator(Class machineClass, InstructionTable.CpuBehavior cpuType, String romFile) throws Exception {
+        this.breakpoints = new Breakpoints(this);

-        bus.addDevice(ram);
-        bus.addDevice(via);
-        bus.addDevice(acia);
-        bus.addDevice(crtc);
+        this.machine = (Machine) machineClass.getConstructors()[0].newInstance(romFile);
+        this.machine.getCpu().setBehavior(cpuType);

-        // TODO: Make this configurable, of course.
-        File romImage = new File("rom.bin");
-        if (romImage.canRead()) {
-            logger.info("Loading ROM image from file " + romImage);
-            this.rom = Memory.makeROM(ROM_BASE, ROM_BASE + ROM_SIZE - 1, romImage);
+
+        // Initialize final fields in the constructor.
+        this.traceLog = new TraceLog();
+        this.memoryWindow = new MemoryWindow(machine.getBus());
+        this.breakpointsWindow = new BreakpointsWindow(breakpoints, mainWindow);
+
+        if (machine.getCrtc() != null) {
+            videoWindow = new VideoWindow(machine.getCrtc(), 2, 2);
        } else {
-            logger.info("Default ROM file " + romImage +
-                        " not found, loading empty R/W memory image.");
-            this.rom = Memory.makeRAM(ROM_BASE, ROM_BASE + ROM_SIZE - 1);
+            videoWindow = null;
        }
-
-        bus.addDevice(rom);
    }

    /**
@@ -186,13 +164,13 @@ public class Simulator {
     */
    public void createAndShowUi() throws IOException {
        mainWindow = new JFrame();
-        mainWindow.setTitle("Symon 6502 Simulator");
+        mainWindow.setTitle("6502 Simulator - " + machine.getName());
        mainWindow.setResizable(false);
        mainWindow.getContentPane().setLayout(new BorderLayout());

        // UI components used for I/O.
-        this.console = new com.loomcom.symon.ui.Console(80, 25, DEFAULT_FONT);
-        this.statusPane = new StatusPanel();
+        this.console = new com.loomcom.symon.ui.Console(80, 25, DEFAULT_FONT, false);
+        this.statusPane = new StatusPanel(machine);

        console.setBorderWidth(CONSOLE_BORDER_WIDTH);

@@ -210,10 +188,12 @@ public class Simulator {

        runStopButton = new JButton("Run");
        stepButton = new JButton("Step");
-        resetButton = new JButton("Reset");
+        JButton softResetButton = new JButton("Soft Reset");
+        JButton hardResetButton = new JButton("Hard Reset");

-        stepCountBox = new JComboBox(STEPS);
+        stepCountBox = new JComboBox<>(STEPS);
        stepCountBox.addActionListener(new ActionListener() {
+            @Override
            public void actionPerformed(ActionEvent actionEvent) {
                try {
                    JComboBox cb = (JComboBox) actionEvent.getSource();
@@ -228,7 +208,8 @@ public class Simulator {
        buttonContainer.add(runStopButton);
        buttonContainer.add(stepButton);
        buttonContainer.add(stepCountBox);
-        buttonContainer.add(resetButton);
+        buttonContainer.add(softResetButton);
+        buttonContainer.add(hardResetButton);

        // Left side - console
        consoleContainer.add(console, BorderLayout.CENTER);
@@ -241,37 +222,40 @@ public class Simulator {
        mainWindow.getContentPane().add(buttonContainer, BorderLayout.PAGE_END);

        runStopButton.addActionListener(new ActionListener() {
+            @Override
            public void actionPerformed(ActionEvent actionEvent) {
                if (runLoop != null && runLoop.isRunning()) {
-                    handleStop();
+                    Simulator.this.handleStop();
                } else {
-                    handleStart();
+                    Simulator.this.handleStart();
                }
            }
        });

        stepButton.addActionListener(new ActionListener() {
+            @Override
            public void actionPerformed(ActionEvent actionEvent) {
-                handleStep(stepsPerClick);
+                Simulator.this.handleStep(stepsPerClick);
            }
        });

-        resetButton.addActionListener(new ActionListener() {
+        softResetButton.addActionListener(new ActionListener() {
+            @Override
            public void actionPerformed(ActionEvent actionEvent) {
-                handleReset();
+                // If this was a CTRL-click, do a hard reset.
+                Simulator.this.handleReset(false);
            }
        });

-        // Prepare the log window
-        traceLog = new TraceLog();
+        hardResetButton.addActionListener(new ActionListener() {
+            @Override
+            public void actionPerformed(ActionEvent actionEvent) {
+                // If this was a CTRL-click, do a hard reset.
+                Simulator.this.handleReset(true);
+            }
+        });

-        // Prepare the memory window
-        memoryWindow = new MemoryWindow(bus);
-
-        // Composite Video and 6545 CRTC
-        videoWindow = new VideoWindow(crtc, 2, 2);
-
-        mainWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        mainWindow.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

        // The Menu. This comes last, because it relies on other components having
        // already been initialized.
@@ -282,8 +266,21 @@ public class Simulator {
        mainWindow.setVisible(true);

        console.requestFocus();
+        handleReset(false);
    }

+    public MainCommand waitForCommand() {
+        synchronized (commandMonitorObject) {
+            try {
+                commandMonitorObject.wait();
+            } catch (InterruptedException ex) {
+                ex.printStackTrace();
+            }
+        }
+        return command;
+    }
+
+
    private void handleStart() {
        // Shift focus to the console.
        console.requestFocus();
@@ -302,7 +299,7 @@ public class Simulator {
    /*
     * Perform a reset.
     */
-    private void handleReset() {
+    private void handleReset(boolean isColdReset) {
        if (runLoop != null && runLoop.isRunning()) {
            runLoop.requestStop();
            runLoop.interrupt();
@@ -310,22 +307,24 @@ public class Simulator {
        }

        try {
-            logger.log(Level.INFO, "Reset requested. Resetting CPU.");
-            // Reset and clear memory
-            cpu.reset();
+            logger.debug("Reset requested. Resetting CPU.");
+            // Reset CPU
+            machine.getCpu().reset();
            // Clear the console.
            console.reset();
            // Reset the trace log.
            traceLog.reset();
-            // Update status.
-            SwingUtilities.invokeLater(new Runnable() {
-                public void run() {
-                    // Now update the state
-                    statusPane.updateState(cpu);
+            // If we're doing a cold reset, clear the memory.
+            if (isColdReset) {
+                Memory mem = machine.getRam();
+                if (mem != null) {
+                    mem.fill(0);
                }
-            });
+            }
+            // Update status.
+            updateVisibleState();
        } catch (MemoryAccessException ex) {
-            logger.log(Level.SEVERE, "Exception during simulator reset: " + ex.getMessage());
+            logger.error("Exception during simulator reset", ex);
        }
    }

@@ -337,16 +336,9 @@ public class Simulator {
            for (int i = 0; i < numSteps; i++) {
                step();
            }
-            SwingUtilities.invokeLater(new Runnable() {
-                public void run() {
-                    if (traceLog.isVisible()) {
-                        traceLog.refresh();
-                    }
-                    statusPane.updateState(cpu);
-                }
-            });
+            updateVisibleState();
        } catch (SymonException ex) {
-            logger.log(Level.SEVERE, "Exception during simulator step: " + ex.getMessage());
+            logger.error("Exception during simulator step", ex);
            ex.printStackTrace();
        }
    }
@@ -355,46 +347,41 @@ public class Simulator {
     * Perform a single step of the simulated system.
     */
    private void step() throws MemoryAccessException {
-        cpu.step();
+        machine.getCpu().step();

-        traceLog.append(cpu.getCpuState());
+        traceLog.append(machine.getCpu().getCpuState());

        // Read from the ACIA and immediately update the console if there's
        // output ready.
-        if (acia.hasTxChar()) {
+        if (machine.getAcia() != null && machine.getAcia().hasTxChar()) {
            // This is thread-safe
-            console.print(Character.toString((char) acia.txRead()));
+            console.print(Character.toString((char) machine.getAcia().txRead(true)));
            console.repaint();
        }

        // If a key has been pressed, fill the ACIA.
-        // TODO: Interrupt handling.
        try {
-            if (console.hasInput()) {
-                acia.rxWrite((int) console.readInputChar());
+            if (machine.getAcia() != null && console.hasInput()) {
+                machine.getAcia().rxWrite((int) console.readInputChar());
            }
        } catch (FifoUnderrunException ex) {
-            logger.severe("Console type-ahead buffer underrun!");
+            logger.error("Console type-ahead buffer underrun!");
        }

-        if (stepsSinceLastCrtcRefresh++ > stepsBetweenCrtcRefreshes) {
-            videoWindow.refreshDisplay();
+        if (videoWindow != null && stepsSinceLastCrtcRefresh++ > STEPS_BETWEEN_CRTC_REFRESHES) {
            stepsSinceLastCrtcRefresh = 0;
+            if (videoWindow.isVisible()) {
+                videoWindow.repaint();
+            }
        }

        // This is a very expensive update, and we're doing it without
        // a delay, so we don't want to overwhelm the Swing event processing thread
        // with requests. Limit the number of ui updates that can be performed.
        if (stepsSinceLastUpdate++ > MAX_STEPS_BETWEEN_UPDATES) {
-            SwingUtilities.invokeLater(new Runnable() {
-                public void run() {
-                    // Now update the state
-                    statusPane.updateState(cpu);
-                }
-            });
+            updateVisibleState();
            stepsSinceLastUpdate = 0;
        }
-
    }

    /**
@@ -403,49 +390,20 @@ public class Simulator {
    private void loadProgram(byte[] program, int startAddress) throws MemoryAccessException {
        int addr = startAddress, i;
        for (i = 0; i < program.length; i++) {
-            bus.write(addr++, program[i] & 0xff);
+            machine.getBus().write(addr++, program[i] & 0xff);
        }

-        logger.log(Level.INFO, "Loaded " + i + " bytes at address 0x" +
-                               Integer.toString(startAddress, 16));
+        logger.info("Loaded {} bytes at address 0x{}", i, Integer.toString(startAddress, 16));

        // After loading, be sure to reset and
        // Reset (but don't clear memory, naturally)
-        cpu.reset();
+        machine.getCpu().reset();

        // Reset the stack program counter
-        cpu.setProgramCounter(preferences.getProgramStartAddress());
+        machine.getCpu().setProgramCounter(preferences.getProgramStartAddress());

        // Immediately update the UI.
-        SwingUtilities.invokeLater(new Runnable() {
-            public void run() {
-                // Now update the state
-                statusPane.updateState(cpu);
-            }
-        });
-    }
-
-    /**
-     * Main entry point to the simulator. Creates a simulator and shows the main
-     * window.
-     *
-     * @param args
-     */
-    public static void main(String args[]) {
-        SwingUtilities.invokeLater(new Runnable() {
-            public void run() {
-                try {
-                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
-                    // Create the main UI window
-                    Simulator simulator = new Simulator();
-                    simulator.createAndShowUi();
-                    // Reset the simulator.
-                    simulator.handleReset();
-                } catch (Exception e) {
-                    e.printStackTrace();
-                }
-            }
-        });
+        updateVisibleState();
    }

    /**
@@ -463,10 +421,11 @@ public class Simulator {
        }

        public void run() {
-            logger.log(Level.INFO, "Starting main run loop.");
+            logger.debug("Starting main run loop.");
            isRunning = true;

            SwingUtilities.invokeLater(new Runnable() {
+                @Override
                public void run() {
                    // Don't allow step while the simulator is running
                    stepButton.setEnabled(false);
@@ -482,13 +441,14 @@ public class Simulator {
                    step();
                } while (shouldContinue());
            } catch (SymonException ex) {
-                logger.log(Level.SEVERE, "Exception in main simulator run thread. Exiting run.");
-                ex.printStackTrace();
+                logger.error("Exception in main simulator run thread. Exiting run.", ex);
            }

            SwingUtilities.invokeLater(new Runnable() {
+                @Override
                public void run() {
-                    statusPane.updateState(cpu);
+                    statusPane.updateState();
+                    memoryWindow.updateState();
                    runStopButton.setText("Run");
                    stepButton.setEnabled(true);
                    stepCountBox.setEnabled(true);
@@ -497,7 +457,6 @@ public class Simulator {
                    }
                    menuBar.simulatorDidStop();
                    traceLog.simulatorDidStop();
-                    // TODO: Update memory window, if frame is visible.
                }
            });

@@ -505,15 +464,19 @@ public class Simulator {
        }

        /**
-         * Returns true if the run loop should proceed to the next step.
-         *
         * @return True if the run loop should proceed to the next step.
         */
        private boolean shouldContinue() {
-            return isRunning && !(preferences.getHaltOnBreak() && cpu.getInstruction() == 0x00);
+            return !breakpoints.contains(machine.getCpu().getProgramCounter()) &&
+                    isRunning &&
+                    !(preferences.getHaltOnBreak() && machine.getCpu().getInstruction() == 0x00);
        }
    }

+    public String disassembleOpAtAddress(int address) throws MemoryAccessException {
+        return machine.getCpu().disassembleOpAtAddress(address);
+    }
+
    class LoadProgramAction extends AbstractAction {
        public LoadProgramAction() {
            super("Load Program...", null);
@@ -522,7 +485,6 @@ public class Simulator {
        }

        public void actionPerformed(ActionEvent actionEvent) {
-            // TODO: Error dialogs on failure.
            try {
                int retVal = fileChooser.showOpenDialog(mainWindow);
                if (retVal == JFileChooser.APPROVE_OPTION) {
@@ -530,8 +492,11 @@ public class Simulator {
                    if (f.canRead()) {
                        long fileSize = f.length();

-                        if (fileSize > MEMORY_SIZE) {
-                            throw new IOException("Program will not fit in available memory.");
+                        if (fileSize > machine.getMemorySize()) {
+                            throw new IOException("File will not fit in " +
+                                    "available memory ($" +
+                                    Integer.toString(machine.getMemorySize(), 16) +
+                                    " bytes)");
                        } else {
                            byte[] program = new byte[(int) fileSize];
                            int i = 0;
@@ -542,21 +507,32 @@ public class Simulator {
                                program[i++] = dis.readByte();
                            }

+                            // Now load the program at the starting address.
+                            loadProgram(program, preferences.getProgramStartAddress());
+
                            SwingUtilities.invokeLater(new Runnable() {
+                                @Override
                                public void run() {
                                    console.reset();
+                                    breakpoints.refresh();
                                }
                            });

-                            // Now load the program at the starting address.
-                            loadProgram(program, preferences.getProgramStartAddress());
+                            // TODO: "Don't Show Again" checkbox
+                            JOptionPane.showMessageDialog(mainWindow,
+                                    "Loaded Successfully At " +
+                                            String.format("$%04X", preferences.getProgramStartAddress()),
+                                    "OK",
+                                    JOptionPane.PLAIN_MESSAGE);
                        }
                    }
                }
            } catch (IOException ex) {
-                logger.log(Level.SEVERE, "Unable to read program file: " + ex.getMessage());
+                logger.error("Unable to read program file.", ex);
+                JOptionPane.showMessageDialog(mainWindow, ex.getMessage(), "Failure", JOptionPane.ERROR_MESSAGE);
            } catch (MemoryAccessException ex) {
-                logger.log(Level.SEVERE, "Memory access error loading program: " + ex.getMessage());
+                logger.error("Memory access error loading program", ex);
+                JOptionPane.showMessageDialog(mainWindow, ex.getMessage(), "Failure", JOptionPane.ERROR_MESSAGE);
            }
        }
    }
@@ -569,7 +545,6 @@ public class Simulator {
        }

        public void actionPerformed(ActionEvent actionEvent) {
-            // TODO: Error dialogs on failure.
            try {
                int retVal = fileChooser.showOpenDialog(mainWindow);
                if (retVal == JFileChooser.APPROVE_OPTION) {
@@ -577,31 +552,42 @@ public class Simulator {
                    if (romFile.canRead()) {
                        long fileSize = romFile.length();

-                        if (fileSize != ROM_SIZE) {
-                            throw new IOException("ROM file must be exactly " + String.valueOf(ROM_SIZE) + " bytes.");
-                        } else {
-                            if (rom != null) {
-                                // Unload the existing ROM image.
-                                bus.removeDevice(rom);
-                            }
-                            // Load the new ROM image
-                            rom = Memory.makeROM(ROM_BASE, ROM_BASE + ROM_SIZE - 1, romFile);
-                            bus.addDevice(rom);
-
-                            // Now, reset
-                            cpu.reset();
-
-                            logger.log(Level.INFO, "ROM File `" + romFile.getName() + "' loaded at " +
-                                                   String.format("0x%04X", ROM_BASE));
+                        if (fileSize != machine.getRomSize()) {
+                            throw new IOException("ROM file must be exactly " + String.valueOf(machine.getRomSize()) + " bytes.");
                        }
+
+                        // Load the new ROM image
+                        Memory rom = Memory.makeROM(machine.getRomBase(), machine.getRomBase() + machine.getRomSize() - 1, romFile);
+                        machine.setRom(rom);
+
+                        // Now, reset
+                        machine.getCpu().reset();
+
+                        updateVisibleState();
+
+                        // Refresh breakpoints to show new memory contents.
+                        breakpoints.refresh();
+
+                        logger.info("ROM File `{}' loaded at {}", romFile.getName(),
+                                String.format("0x%04X", machine.getRomBase()));
+                        // TODO: "Don't Show Again" checkbox
+                        JOptionPane.showMessageDialog(mainWindow,
+                                "Loaded Successfully At " +
+                                        String.format("$%04X", machine.getRomBase()),
+                                "OK",
+                                JOptionPane.PLAIN_MESSAGE);
+
                    }
                }
            } catch (IOException ex) {
-                logger.log(Level.SEVERE, "Unable to read ROM file: " + ex.getMessage());
+                logger.error("Unable to read ROM file: {}", ex.getMessage());
+                JOptionPane.showMessageDialog(mainWindow, ex.getMessage(), "Failure", JOptionPane.ERROR_MESSAGE);
            } catch (MemoryRangeException ex) {
-                logger.log(Level.SEVERE, "Memory range error while loading ROM file: " + ex.getMessage());
+                logger.error("Memory range error while loading ROM file: {}", ex.getMessage());
+                JOptionPane.showMessageDialog(mainWindow, ex.getMessage(), "Failure", JOptionPane.ERROR_MESSAGE);
            } catch (MemoryAccessException ex) {
-                logger.log(Level.SEVERE, "Memory access error while loading ROM file: " + ex.getMessage());
+                logger.error("Memory access error while loading ROM file: {}", ex.getMessage());
+                JOptionPane.showMessageDialog(mainWindow, ex.getMessage(), "Failure", JOptionPane.ERROR_MESSAGE);
            }
        }
    }
@@ -618,6 +604,32 @@ public class Simulator {
        }
    }

+    class SelectMachineAction extends AbstractAction {
+        public SelectMachineAction() {
+            super("Switch emulated machine...", null);
+            putValue(SHORT_DESCRIPTION, "Select the type of the machine to be emulated");
+            putValue(MNEMONIC_KEY, KeyEvent.VK_M);
+        }
+
+        public void actionPerformed(ActionEvent actionEvent) {
+            if (runLoop != null) {
+                runLoop.requestStop();
+            }
+
+            memoryWindow.dispose();
+            traceLog.dispose();
+            if (videoWindow != null) {
+                videoWindow.dispose();
+            }
+            mainWindow.dispose();
+
+            command = MainCommand.SELECTMACHINE;
+            synchronized (commandMonitorObject) {
+                commandMonitorObject.notifyAll();
+            }
+        }
+    }
+
    class QuitAction extends AbstractAction {
        public QuitAction() {
            super("Quit", null);
@@ -640,11 +652,12 @@ public class Simulator {
        public SetFontAction(int size) {
            super(Integer.toString(size) + " pt", null);
            this.size = size;
-            putValue(SHORT_DESCRIPTION, "Set font to " + Integer.toString(size) + "pt.");
+            putValue(SHORT_DESCRIPTION, "Set font to " + size + "pt.");
        }

        public void actionPerformed(ActionEvent actionEvent) {
            SwingUtilities.invokeLater(new Runnable() {
+                @Override
                public void run() {
                    console.setFont(new Font("Monospaced", Font.PLAIN, size));
                    mainWindow.pack();
@@ -653,6 +666,40 @@ public class Simulator {
        }
    }

+    class SetSpeedAction extends AbstractAction {
+        private int speed;
+
+        public SetSpeedAction(int speed) {
+            super(Integer.toString(speed) + " MHz", null);
+            this.speed = speed;
+            putValue(SHORT_DESCRIPTION, "Set simulated speed to " + speed + " MHz.");
+        }
+
+        @Override
+        public void actionPerformed(ActionEvent actionEvent) {
+            if (speed < 1 || speed > CLOCK_PERIODS.length - 1) {
+                return;
+            }
+
+            machine.getCpu().setClockPeriodInNs(CLOCK_PERIODS[speed]);
+        }
+    }
+
+    class SetCpuAction extends AbstractAction {
+        private Cpu.CpuBehavior behavior;
+
+        public SetCpuAction(String cpu, Cpu.CpuBehavior behavior) {
+            super(cpu, null);
+            this.behavior = behavior;
+            putValue(SHORT_DESCRIPTION, "Set CPU to " + cpu);
+        }
+
+        @Override
+        public void actionPerformed(ActionEvent actionEvent) {
+            machine.getCpu().setBehavior(behavior);
+        }
+    }
+
    class ToggleTraceWindowAction extends AbstractAction {
        public ToggleTraceWindowAction() {
            super("Trace Log", null);
@@ -705,6 +752,23 @@ public class Simulator {
        }
    }

+    class ToggleBreakpointWindowAction extends AbstractAction {
+        public ToggleBreakpointWindowAction() {
+            super("Breakpoints...", null);
+            putValue(SHORT_DESCRIPTION, "Show or Hide Breakpoints");
+        }
+
+        public void actionPerformed(ActionEvent actionEvent) {
+            synchronized (breakpointsWindow) {
+                if (breakpointsWindow.isVisible()) {
+                    breakpointsWindow.setVisible(false);
+                } else {
+                    breakpointsWindow.setVisible(true);
+                }
+            }
+        }
+    }
+
    class SimulatorMenu extends JMenuBar {
        // Menu Items
        private JMenuItem loadProgramItem;
@@ -722,7 +786,9 @@ public class Simulator {
         */
        public void simulatorDidStart() {
            loadProgramItem.setEnabled(false);
-            loadRomItem.setEnabled(false);
+            if (loadRomItem != null) {
+                loadRomItem.setEnabled(false);
+            }
        }

        /**
@@ -730,7 +796,9 @@ public class Simulator {
         */
        public void simulatorDidStop() {
            loadProgramItem.setEnabled(true);
-            loadRomItem.setEnabled(true);
+            if (loadRomItem != null) {
+                loadRomItem.setEnabled(true);
+            }
        }

        private void initMenu() {
@@ -741,13 +809,19 @@ public class Simulator {
            JMenu fileMenu = new JMenu("File");

            loadProgramItem = new JMenuItem(new LoadProgramAction());
-            loadRomItem = new JMenuItem(new LoadRomAction());
-            JMenuItem prefsItem = new JMenuItem(new ShowPrefsAction());
-            JMenuItem quitItem = new JMenuItem(new QuitAction());
-
            fileMenu.add(loadProgramItem);
-            fileMenu.add(loadRomItem);
+
+            // Simple Machine does not implement a ROM, so it makes no sense to
+            // offer a ROM load option.
+            if (machine.getRom() != null) {
+                loadRomItem = new JMenuItem(new LoadRomAction());
+                fileMenu.add(loadRomItem);
+            }
+
+            JMenuItem prefsItem = new JMenuItem(new ShowPrefsAction());
            fileMenu.add(prefsItem);
+
+            JMenuItem quitItem = new JMenuItem(new QuitAction());
            fileMenu.add(quitItem);

            add(fileMenu);
@@ -792,26 +866,111 @@ public class Simulator {
            });
            viewMenu.add(showMemoryTable);

-            final JCheckBoxMenuItem showVideoWindow = new JCheckBoxMenuItem(new ToggleVideoWindowAction());
-            videoWindow.addWindowListener(new WindowAdapter() {
-                @Override
-                public void windowClosing(WindowEvent e) {
-                    showVideoWindow.setSelected(false);
-                }
-            });
-            viewMenu.add(showVideoWindow);
+            if (videoWindow != null) {
+                final JCheckBoxMenuItem showVideoWindow = new JCheckBoxMenuItem(new ToggleVideoWindowAction());
+                videoWindow.addWindowListener(new WindowAdapter() {
+                    @Override
+                    public void windowClosing(WindowEvent e) {
+                        showVideoWindow.setSelected(false);
+                    }
+                });
+                viewMenu.add(showVideoWindow);
+            }

            add(viewMenu);
+
+            /*
+             * Simulator Menu
+             */
+
+
+            JMenu simulatorMenu = new JMenu("Simulator");
+
+            // "Select Machine..." item.
+            JMenuItem selectMachineItem = new JMenuItem(new SelectMachineAction());
+            simulatorMenu.add(selectMachineItem);
+
+            // "CPU" sub-menu
+            JMenu cpuTypeMenu = new JMenu("CPU");
+            ButtonGroup cpuGroup = new ButtonGroup();
+
+            makeCpuMenuItem("6502", Cpu.CpuBehavior.NMOS_6502, cpuTypeMenu, cpuGroup);
+            makeCpuMenuItem("65C02", Cpu.CpuBehavior.CMOS_6502, cpuTypeMenu, cpuGroup);
+            makeCpuMenuItem("65C816", Cpu.CpuBehavior.CMOS_65816, cpuTypeMenu, cpuGroup);
+
+            // "Clock Speed" sub-menu
+            JMenu speedSubMenu = new JMenu("Clock Speed");
+            ButtonGroup speedGroup = new ButtonGroup();
+
+            makeSpeedMenuItem(1, speedSubMenu, speedGroup);
+            makeSpeedMenuItem(2, speedSubMenu, speedGroup);
+            makeSpeedMenuItem(4, speedSubMenu, speedGroup);
+            makeSpeedMenuItem(8, speedSubMenu, speedGroup);
+
+            simulatorMenu.add(speedSubMenu);
+            simulatorMenu.add(cpuTypeMenu);
+
+            // "Breakpoints"
+            final JCheckBoxMenuItem showBreakpoints = new JCheckBoxMenuItem(new ToggleBreakpointWindowAction());
+            // Un-check the menu item if the user closes the window directly
+            breakpointsWindow.addWindowListener(new WindowAdapter() {
+                @Override
+                public void windowClosing(WindowEvent e) {
+                    showBreakpoints.setSelected(false);
+                }
+            });
+            simulatorMenu.add(showBreakpoints);
+
+            add(simulatorMenu);
        }

-        private void makeFontSizeMenuItem(int size, JMenu fontSubMenu, ButtonGroup group) {
+        private void makeFontSizeMenuItem(int size, JMenu subMenu, ButtonGroup group) {
            Action action = new SetFontAction(size);

            JCheckBoxMenuItem item = new JCheckBoxMenuItem(action);
            item.setSelected(size == DEFAULT_FONT_SIZE);
-            fontSubMenu.add(item);
+            subMenu.add(item);
            group.add(item);
        }
+
+        private void makeSpeedMenuItem(int speed, JMenu subMenu, ButtonGroup group) {
+            if (speed < 1 || speed > CLOCK_PERIODS.length - 1) {
+                return;
+            }
+
+            Action action = new SetSpeedAction(speed);
+
+            JCheckBoxMenuItem item = new JCheckBoxMenuItem(action);
+            item.setSelected(CLOCK_PERIODS[speed] == Cpu.DEFAULT_CLOCK_PERIOD_IN_NS);
+            subMenu.add(item);
+            group.add(item);
+        }
+
+        private void makeCpuMenuItem(String cpu, Cpu.CpuBehavior behavior, JMenu subMenu, ButtonGroup group) {
+
+            Action action = new SetCpuAction(cpu, behavior);
+
+            JCheckBoxMenuItem item = new JCheckBoxMenuItem(action);
+            item.setSelected(machine.getCpu().getBehavior() == behavior);
+            subMenu.add(item);
+            group.add(item);
+        }
+
+    }
+
+    private void updateVisibleState() {
+        // Immediately update the UI.
+        SwingUtilities.invokeLater(new Runnable() {
+            @Override
+            public void run() {
+                // Now update the state
+                statusPane.updateState();
+                memoryWindow.updateState();
+                if (traceLog.shouldUpdate()) {
+                    traceLog.refresh();
+                }
+            }
+        });
    }

 }
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008-2013 Seth J. Morabito <sethm@loomcom.com>
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
@@ -23,179 +23,48 @@

 package com.loomcom.symon.devices;

-import com.loomcom.symon.exceptions.MemoryAccessException;
 import com.loomcom.symon.exceptions.MemoryRangeException;


 /**
- * This is a simulation of the MOS 6551 ACIA, with limited
- * functionality.  Interrupts are not supported.
- * <p/>
- * Unlike a 16550 UART, the 6551 ACIA has only one-byte transmit and
- * receive buffers. It is the programmer's responsibility to check the
- * status (full or empty) for transmit and receive buffers before
- * writing / reading.
+ * Abstract base class for ACIAS such as the 6551 and 6580
 */
-public class Acia extends Device {

-    public static final int ACIA_SIZE = 4;
+public abstract class Acia extends Device {

-    static final int DATA_REG = 0;
-    static final int STAT_REG = 1;
-    static final int CMND_REG = 2;
-    static final int CTRL_REG = 3;
+    private String name;

    /**
     * Register addresses
     */
-    private int baseAddress;
+    int baseAddress;

-    /**
-     * Registers. These are ignored in the current implementation.
-     */
-    private int commandRegister;
-    private int controlRegister;
+    boolean receiveIrqEnabled = false;
+    boolean transmitIrqEnabled = false;
+    boolean overrun = false;
+    boolean interrupt = false;

-    private boolean receiveIrqEnabled = false;
-    private boolean transmitIrqEnabled = false;
-    private boolean overrun = false;
-
-    private long lastTxWrite   = 0;
-    private long lastRxRead    = 0;
-    private int  baudRate      = 0;
-    private long baudRateDelay = 0;
+    long lastTxWrite   = 0;
+    long lastRxRead    = 0;
+    int  baudRate      = 0;
+    long baudRateDelay = 0;

    /**
     * Read/Write buffers
     */
-    private int rxChar = 0;
-    private int txChar = 0;
+    int rxChar = 0;
+    int txChar = 0;

-    private boolean rxFull  = false;
-    private boolean txEmpty = true;
+    boolean rxFull  = false;
+    boolean txEmpty = true;

-    public Acia(int address) throws MemoryRangeException {
-        super(address, address + ACIA_SIZE - 1, "ACIA");
+
+    public Acia(int address, int size, String name) throws MemoryRangeException {
+        super(address, address + size - 1, name);
+        this.name = name;
        this.baseAddress = address;
    }

-    @Override
-    public int read(int address) throws MemoryAccessException {
-        switch (address) {
-            case DATA_REG:
-                return rxRead();
-            case STAT_REG:
-                return statusReg();
-            case CMND_REG:
-                return commandRegister;
-            case CTRL_REG:
-                return controlRegister;
-            default:
-                throw new MemoryAccessException("No register.");
-        }
-    }
-
-    @Override
-    public void write(int address, int data) throws MemoryAccessException {
-        switch (address) {
-            case 0:
-                txWrite(data);
-                break;
-            case 1:
-                reset();
-                break;
-            case 2:
-                setCommandRegister(data);
-                break;
-            case 3:
-                setControlRegister(data);
-                break;
-            default:
-                throw new MemoryAccessException("No register.");
-        }
-    }
-
-
-    private void setCommandRegister(int data) {
-        commandRegister = data;
-
-        // Bit 1 controls receiver IRQ behavior
-        receiveIrqEnabled = (commandRegister & 0x02) == 0;
-        // Bits 2 & 3 controls transmit IRQ behavior
-        transmitIrqEnabled = (commandRegister & 0x08) == 0 && (commandRegister & 0x04) != 0;
-    }
-
-    /**
-     * Set the control register and associated state.
-     *
-     * @param data
-     */
-    private void setControlRegister(int data) {
-        controlRegister = data;
-
-        // If the value of the data is 0, this is a request to reset,
-        // otherwise it's a control update.
-
-        if (data == 0) {
-            reset();
-        } else {
-            // Mask the lower three bits to get the baud rate.
-            int baudSelector = data & 0x0f;
-            switch (baudSelector) {
-                case 0:
-                    baudRate = 0;
-                    break;
-                case 1:
-                    baudRate = 50;
-                    break;
-                case 2:
-                    baudRate = 75;
-                    break;
-                case 3:
-                    baudRate = 110; // Real rate is actually 109.92
-                    break;
-                case 4:
-                    baudRate = 135; // Real rate is actually 134.58
-                    break;
-                case 5:
-                    baudRate = 150;
-                    break;
-                case 6:
-                    baudRate = 300;
-                    break;
-                case 7:
-                    baudRate = 600;
-                    break;
-                case 8:
-                    baudRate = 1200;
-                    break;
-                case 9:
-                    baudRate = 1800;
-                    break;
-                case 10:
-                    baudRate = 2400;
-                    break;
-                case 11:
-                    baudRate = 3600;
-                    break;
-                case 12:
-                    baudRate = 4800;
-                    break;
-                case 13:
-                    baudRate = 7200;
-                    break;
-                case 14:
-                    baudRate = 9600;
-                    break;
-                case 15:
-                    baudRate = 19200;
-                    break;
-            }
-
-            // Recalculate the baud rate delay.
-            baudRateDelay = calculateBaudRateDelay();
-        }
-    }

    /*
     * Calculate the delay in nanoseconds between successive read/write operations, based on the
@@ -214,6 +83,7 @@ public class Acia extends Device {
    /**
     * @return The simulated baud rate in bps.
     */
+    @SuppressWarnings("unused")
    public int getBaudRate() {
        return baudRate;
    }
@@ -225,51 +95,52 @@ public class Acia extends Device {
     */
    public void setBaudRate(int rate) {
        this.baudRate = rate;
+		this.baudRateDelay = calculateBaudRateDelay();
    }

    /**
     * @return The contents of the status register.
     */
-    public int statusReg() {
-        // TODO: Overrun, Parity Error, Framing Error, DTR, DSR, and Interrupt flags.
-        int stat = 0;
-        if (rxFull && System.nanoTime() >= (lastRxRead + baudRateDelay)) {
-            stat |= 0x08;
-        }
-        if (txEmpty && System.nanoTime() >= (lastTxWrite + baudRateDelay)) {
-            stat |= 0x10;
-        }
-        return stat;
-    }
+    public abstract int statusReg(boolean cpuAccess);

    @Override
    public String toString() {
-        return "ACIA@" + String.format("%04X", baseAddress);
+        return name + "@" + String.format("%04X", baseAddress);
    }

-    public synchronized int rxRead() {
-        lastRxRead = System.nanoTime();
-        rxFull = false;
+    public synchronized int rxRead(boolean cpuAccess) {
+        if (cpuAccess) {
+            lastRxRead = System.nanoTime();
+            overrun = false;
+            rxFull = false;
+        }
        return rxChar;
    }

    public synchronized void rxWrite(int data) {
+        if (rxFull) {
+            overrun = true;
+        }
+
        rxFull = true;

        if (receiveIrqEnabled) {
+            interrupt = true;
            getBus().assertIrq();
        }

        rxChar = data;
    }

-    public synchronized int txRead() {
-        txEmpty = true;
+    public synchronized int txRead(boolean cpuAccess) {
+        if (cpuAccess) {
+            txEmpty = true;

-        if (transmitIrqEnabled) {
-            getBus().assertIrq();
+            if (transmitIrqEnabled) {
+                interrupt = true;
+                getBus().assertIrq();
+            }
        }
-
        return txChar;
    }

@@ -289,17 +160,9 @@ public class Acia extends Device {
    /**
     * @return true if there is character data in the RX register.
     */
+    @SuppressWarnings("unused")
    public boolean hasRxChar() {
        return rxFull;
    }

-    private synchronized void reset() {
-        txChar = 0;
-        txEmpty = true;
-        rxChar = 0;
-        rxFull = false;
-        receiveIrqEnabled = false;
-        transmitIrqEnabled = false;
-    }
-
 }
@@ -0,0 +1,215 @@
+/*
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+package com.loomcom.symon.devices;
+
+import com.loomcom.symon.exceptions.MemoryAccessException;
+import com.loomcom.symon.exceptions.MemoryRangeException;
+
+/**
+ * This is a simulation of the MOS 6551 ACIA, with limited
+ * functionality.  Interrupts are not supported.
+ * <p/>
+ * Unlike a 16550 UART, the 6551 ACIA has only one-byte transmit and
+ * receive buffers. It is the programmer's responsibility to check the
+ * status (full or empty) for transmit and receive buffers before
+ * writing / reading.
+ */
+public class Acia6551 extends Acia {
+
+    public static final int ACIA_SIZE = 4;
+
+    static final int DATA_REG = 0;
+    static final int STAT_REG = 1;
+    static final int CMND_REG = 2;
+    static final int CTRL_REG = 3;
+
+    /**
+     * Registers. These are ignored in the current implementation.
+     */
+    private int commandRegister;
+    private int controlRegister;
+
+
+    public Acia6551(int address) throws MemoryRangeException {
+        super(address, ACIA_SIZE, "ACIA");
+    }
+
+    @Override
+    public int read(int address, boolean cpuAccess) throws MemoryAccessException {
+        switch (address) {
+            case DATA_REG:
+                return rxRead(cpuAccess);
+            case STAT_REG:
+                return statusReg(cpuAccess);
+            case CMND_REG:
+                return commandRegister;
+            case CTRL_REG:
+                return controlRegister;
+            default:
+                throw new MemoryAccessException("No register.");
+        }
+    }
+
+    @Override
+    public void write(int address, int data) throws MemoryAccessException {
+        switch (address) {
+            case 0:
+                txWrite(data);
+                break;
+            case 1:
+                reset();
+                break;
+            case 2:
+                setCommandRegister(data);
+                break;
+            case 3:
+                setControlRegister(data);
+                break;
+            default:
+                throw new MemoryAccessException("No register.");
+        }
+    }
+
+
+    private void setCommandRegister(int data) {
+        commandRegister = data;
+
+        // Bit 1 controls receiver IRQ behavior
+        receiveIrqEnabled = (commandRegister & 0x02) == 0;
+        // Bits 2 & 3 controls transmit IRQ behavior
+        transmitIrqEnabled = (commandRegister & 0x08) == 0 && (commandRegister & 0x04) != 0;
+    }
+
+    /**
+     * Set the control register and associated state.
+     *
+     * @param data Data to write into the control register
+     */
+    private void setControlRegister(int data) {
+        controlRegister = data;
+        int rate = 0;
+
+        // If the value of the data is 0, this is a request to reset,
+        // otherwise it's a control update.
+
+        if (data == 0) {
+            reset();
+        } else {
+            // Mask the lower three bits to get the baud rate.
+            int baudSelector = data & 0x0f;
+            switch (baudSelector) {
+                case 0:
+                    rate = 0;
+                    break;
+                case 1:
+                    rate = 50;
+                    break;
+                case 2:
+                    rate = 75;
+                    break;
+                case 3:
+                    rate = 110; // Real rate is actually 109.92
+                    break;
+                case 4:
+                    rate = 135; // Real rate is actually 134.58
+                    break;
+                case 5:
+                    rate = 150;
+                    break;
+                case 6:
+                    rate = 300;
+                    break;
+                case 7:
+                    rate = 600;
+                    break;
+                case 8:
+                    rate = 1200;
+                    break;
+                case 9:
+                    rate = 1800;
+                    break;
+                case 10:
+                    rate = 2400;
+                    break;
+                case 11:
+                    rate = 3600;
+                    break;
+                case 12:
+                    rate = 4800;
+                    break;
+                case 13:
+                    rate = 7200;
+                    break;
+                case 14:
+                    rate = 9600;
+                    break;
+                case 15:
+                    rate = 19200;
+                    break;
+            }
+
+            setBaudRate(rate);
+        }
+    }
+
+
+    /**
+     * @return The contents of the status register.
+     */
+    @Override
+    public int statusReg(boolean cpuAccess) {
+        // TODO: Parity Error, Framing Error, DTR, and DSR flags.
+        int stat = 0;
+        if (rxFull && System.nanoTime() >= (lastRxRead + baudRateDelay)) {
+            stat |= 0x08;
+        }
+        if (txEmpty && System.nanoTime() >= (lastTxWrite + baudRateDelay)) {
+            stat |= 0x10;
+        }
+        if (overrun) {
+            stat |= 0x04;
+        }
+        if (interrupt) {
+            stat |= 0x80;
+        }
+
+        if (cpuAccess) {
+            interrupt = false;
+        }
+
+        return stat;
+    }
+
+
+    private synchronized void reset() {
+        txChar = 0;
+        txEmpty = true;
+        rxChar = 0;
+        rxFull = false;
+        receiveIrqEnabled = false;
+        transmitIrqEnabled = false;
+        interrupt = false;
+    }
+
+}
@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
+ *                    Maik Merten <maikmerten@googlemail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+package com.loomcom.symon.devices;
+
+import com.loomcom.symon.exceptions.MemoryAccessException;
+import com.loomcom.symon.exceptions.MemoryRangeException;
+
+
+/**
+ * This is a simulation of the Motorola 6850 ACIA, with limited
+ * functionality.
+ *
+ * Unlike a 16550 UART, the 6850 ACIA has only one-byte transmit and
+ * receive buffers. It is the programmer's responsibility to check the
+ * status (full or empty) for transmit and receive buffers before
+ * writing / reading.
+ */
+public class Acia6850 extends Acia {
+
+    public static final int ACIA_SIZE = 2;
+
+    static final int STAT_REG = 0;	// read-only
+    static final int CTRL_REG = 0;	// write-only
+
+    static final int RX_REG = 1;	// read-only
+    static final int TX_REG = 1;	// write-only
+
+    public Acia6850(int address) throws MemoryRangeException {
+        super(address, ACIA_SIZE, "ACIA6850");
+        setBaudRate(2400);
+    }
+
+    @Override
+    public int read(int address, boolean cpuAccess) throws MemoryAccessException {
+        switch (address) {
+            case RX_REG:
+                return rxRead(cpuAccess);
+            case STAT_REG:
+                return statusReg(cpuAccess);
+
+            default:
+                throw new MemoryAccessException("No register.");
+        }
+    }
+
+    @Override
+    public void write(int address, int data) throws MemoryAccessException {
+        switch (address) {
+            case TX_REG:
+                txWrite(data);
+                break;
+            case CTRL_REG:
+                setCommandRegister(data);
+                break;
+            default:
+                throw new MemoryAccessException("No register.");
+        }
+    }
+
+    private void setCommandRegister(int data) {
+        // Bits 0 & 1 control the master reset
+        if((data & 0x01) != 0 && (data & 0x02) != 0) {
+            reset();
+        }
+
+        // Bit 7 controls receiver IRQ behavior
+        receiveIrqEnabled = (data & 0x80) != 0;
+        // Bits 5 & 6 controls transmit IRQ behavior
+        transmitIrqEnabled = (data & 0x20) != 0 && (data & 0x40) == 0;
+    }
+
+
+
+    /**
+     * @return The contents of the status register.
+     */
+    @Override
+    public int statusReg(boolean cpuAccess) {
+        // TODO: Parity Error, Framing Error, DTR, and DSR flags.
+        int stat = 0;
+        if (rxFull && System.nanoTime() >= (lastRxRead + baudRateDelay)) {
+            stat |= 0x01;
+        }
+        if (txEmpty && System.nanoTime() >= (lastTxWrite + baudRateDelay)) {
+            stat |= 0x02;
+        }
+        if (overrun) {
+            stat |= 0x20;
+        }
+        if (interrupt) {
+            stat |= 0x80;
+        }
+
+        if (cpuAccess) {
+            interrupt = false;
+        }
+
+        return stat;
+    }
+
+
+    private synchronized void reset() {
+        overrun = false;
+        rxFull = false;
+        txEmpty = true;
+        interrupt = false;
+    }
+
+}
@@ -1,20 +1,37 @@
+/*
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
 package com.loomcom.symon.devices;

 import com.loomcom.symon.exceptions.MemoryAccessException;
 import com.loomcom.symon.exceptions.MemoryRangeException;

 import java.io.IOException;
-import java.util.logging.Logger;
-

 /**
 * Simulation of a 6545 CRTC and virtual CRT output.
 */
 public class Crtc extends Device {
-
-    private static final Logger logger = Logger.getLogger(Crtc.class.getName());
-
-
    // Memory locations in the CRTC address space
    public static final int REGISTER_SELECT          = 0;
    public static final int REGISTER_RW              = 1;
@@ -65,6 +82,11 @@ public class Crtc extends Device {

    private int currentRegister = 0;

+    // Status bits
+    private boolean rowColumnAddressing = false;
+    private boolean displayEnableSkew = false;
+    private boolean cursorSkew = false;
+
    private Memory memory;

    public Crtc(int deviceAddress, Memory memory) throws MemoryRangeException, IOException {
@@ -97,7 +119,7 @@ public class Crtc extends Device {
    }

    @Override
-    public int read(int address) throws MemoryAccessException {
+    public int read(int address, boolean cpuAccess) throws MemoryAccessException {
        switch (address) {
            case REGISTER_RW:
                switch (currentRegister) {
@@ -118,8 +140,9 @@ public class Crtc extends Device {
        return null;
    }

-    public int[] getDmaAccess() {
-        return memory.getDmaAccess();
+    public int getCharAtAddress(int address) throws MemoryAccessException {
+        // TODO: Row/Column addressing
+        return memory.read(address, false);
    }

    public int getHorizontalDisplayed() {
@@ -162,6 +185,18 @@ public class Crtc extends Device {
        return pageSize;
    }

+    public boolean getRowColumnAddressing() {
+        return rowColumnAddressing;
+    }
+
+    public boolean getDisplayEnableSkew() {
+        return displayEnableSkew;
+    }
+
+    public boolean getCursorSkew() {
+        return cursorSkew;
+    }
+
    private void setCurrentRegister(int registerNumber) {
        this.currentRegister = registerNumber;
    }
@@ -180,7 +215,9 @@ public class Crtc extends Device {
                pageSize = horizontalDisplayed * verticalDisplayed;
                break;
            case MODE_CONTROL:
-                // TODO: Implement multiple addressing modes and cursor skew.
+                rowColumnAddressing = (data & 0x04) != 0;
+                displayEnableSkew = (data & 0x10) != 0;
+                cursorSkew = (data & 0x20) != 0;
                break;
            case SCAN_LINE:
                scanLinesPerRow = data;
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008-2013 Seth J. Morabito <sethm@loomcom.com>
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
@@ -62,22 +62,17 @@ public abstract class Device implements Comparable<Device> {
     */
    private Set<DeviceChangeListener> deviceChangeListeners;

-    public Device(int startAddress, int endAddress, String name)
-            throws MemoryRangeException {
+    public Device(int startAddress, int endAddress, String name) throws MemoryRangeException {
        this.memoryRange = new MemoryRange(startAddress, endAddress);
        this.size = endAddress - startAddress + 1;
        this.name = name;
-        this.deviceChangeListeners = new HashSet<DeviceChangeListener>();
-    }
-
-    public Device(int startAddress, int endAddress) throws MemoryRangeException {
-        this(startAddress, endAddress, null);
+        this.deviceChangeListeners = new HashSet<>();
    }

    /* Methods required to be implemented by inheriting classes. */
    public abstract void write(int address, int data) throws MemoryAccessException;

-    public abstract int read(int address) throws MemoryAccessException;
+    public abstract int read(int address, boolean cpuAccess) throws MemoryAccessException;

    public abstract String toString();

@@ -97,6 +92,7 @@ public abstract class Device implements Comparable<Device> {
        return memoryRange.endAddress();
    }

+    @SuppressWarnings("unused")
    public int startAddress() {
        return memoryRange.startAddress();
    }
@@ -105,6 +101,7 @@ public abstract class Device implements Comparable<Device> {
        return name;
    }

+    @SuppressWarnings("unused")
    public void setName(String name) {
        this.name = name;
    }
@@ -118,8 +115,8 @@ public abstract class Device implements Comparable<Device> {
    }

    public void notifyListeners() {
-        for (DeviceChangeListener l : deviceChangeListeners) {
-            l.deviceStateChanged();
+        for (DeviceChangeListener listener : deviceChangeListeners) {
+            listener.deviceStateChanged();
        }
    }

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013 Seth J. Morabito <web@loomcom.com>
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
@@ -24,5 +24,5 @@
 package com.loomcom.symon.devices;

 public interface DeviceChangeListener {
-    public void deviceStateChanged();
+    void deviceStateChanged();
 }
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008-2013 Seth J. Morabito <sethm@loomcom.com>
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
@@ -28,8 +28,6 @@ import java.util.*;

 import com.loomcom.symon.exceptions.*;

-import javax.swing.*;
-
 public class Memory extends Device {

    private boolean readOnly;
@@ -57,8 +55,7 @@ public class Memory extends Device {
    }

    public static Memory makeRAM(int startAddress, int endAddress) throws MemoryRangeException {
-        Memory memory = new Memory(startAddress, endAddress, false);
-        return memory;
+        return new Memory(startAddress, endAddress, false);
    }

    public void write(int address, int data) throws MemoryAccessException {
@@ -97,7 +94,7 @@ public class Memory extends Device {

    }

-    public int read(int address) throws MemoryAccessException {
+    public int read(int address, boolean cpuAccess) throws MemoryAccessException {
        return this.mem[address];
    }

@@ -108,8 +105,4 @@ public class Memory extends Device {
    public String toString() {
        return "Memory: " + getMemoryRange().toString();
    }
-
-    public int[] getDmaAccess() {
-        return mem;
-    }
 }
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008-2013 Seth J. Morabito <sethm@loomcom.com>
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
@@ -23,45 +23,19 @@

 package com.loomcom.symon.devices;

-import com.loomcom.symon.exceptions.MemoryAccessException;
 import com.loomcom.symon.exceptions.MemoryRangeException;

-public class Via extends Device {
-    public static final int VIA_SIZE = 16;
+public abstract class Pia extends Device {

-    private static final int ORB = 0;
-    private static final int ORA = 1;
-    private static final int DDRB = 2;
-    private static final int DDRA = 3;
-    private static final int T1C_L = 4;
-    private static final int T1C_H = 5;
-    private static final int T1L_L = 6;
-    private static final int T1L_H = 7;
-    private static final int T2C_L = 8;
-    private static final int T2C_H = 9;
-    private static final int SR = 10;
-    private static final int ACR = 11;
-    private static final int PCR = 12;
-    private static final int IFR = 13;
-    private static final int IER = 14;
-    private static final int ORA_H = 15;
+    private final String name;

-    public Via(int address) throws MemoryRangeException {
-      super(address, address + VIA_SIZE - 1, "VIA");
-    }
-
-    @Override
-    public void write(int address, int data) throws MemoryAccessException {
-
-    }
-
-    @Override
-    public int read(int address) throws MemoryAccessException {
-        return 0;
+    public Pia(int startAddress, int endAddress, String name) throws MemoryRangeException {
+        super(startAddress, endAddress, name);
+        this.name = name;
    }

    @Override
    public String toString() {
-        return null;
+        return name;
    }
 }
@@ -0,0 +1,210 @@
+/*
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
+ *                    Maik Merten <maikmerten@googlemail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+
+package com.loomcom.symon.devices;
+
+import com.loomcom.symon.exceptions.MemoryAccessException;
+import com.loomcom.symon.exceptions.MemoryRangeException;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * Emulation for the SD-card controller of the MULTICOMP system.
+ * Neiter comlete nor correct.
+ */
+public class SdController extends Device {
+
+    private enum Status {
+        IDLE,
+        READ,
+        WRITE
+    }
+
+    public static final int CONTROLLER_SIZE = 8;
+    private final int SECTOR_SIZE = 512;
+    private final static Logger logger = Logger.getLogger(SdController.class.getName());
+
+    private File sdImageFile;
+    private int lba0, lba1, lba2;
+    private int position;
+    private Status status = Status.IDLE;
+
+    private final byte[] readBuffer = new byte[SECTOR_SIZE];
+    private final byte[] writeBuffer = new byte[SECTOR_SIZE];
+    private int readPosition = 0;
+    private int writePosition = 0;
+
+
+    public SdController(int address) throws MemoryRangeException {
+        super(address, address + CONTROLLER_SIZE - 1, "SDCONTROLLER");
+
+        sdImageFile = new File("sd.img");
+        if (!sdImageFile.exists()) {
+            sdImageFile = null;
+            logger.log(Level.INFO, "Could not find SD card image 'sd.img'");
+        }
+    }
+
+
+    @Override
+    public void write(int address, int data) throws MemoryAccessException {
+        switch (address) {
+            case 0:
+                writeData(data);
+                return;
+            case 1:
+                writeCommand(data);
+                return;
+            case 2:
+                this.lba0 = data;
+                return;
+            case 3:
+                this.lba1 = data;
+                return;
+            case 4:
+                this.lba2 = data;
+        }
+    }
+
+    @Override
+    public int read(int address, boolean cpuAccess) throws MemoryAccessException {
+        switch (address) {
+            case 0:
+                return readData();
+            case 1:
+                return readStatus();
+            default:
+                return 0;
+        }
+    }
+
+    private void computePosition() {
+        this.position = lba0 + (lba1 << 8) + (lba2 << 16);
+        // each sector is 512 bytes, so multiply accordingly
+        this.position <<= 9;
+    }
+
+    private void prepareRead() {
+        this.status = Status.READ;
+        this.readPosition = 0;
+        computePosition();
+
+        if (sdImageFile != null) {
+            try {
+                FileInputStream fis = new FileInputStream(sdImageFile);
+                fis.skip(this.position);
+                int read = fis.read(readBuffer);
+                if (read < SECTOR_SIZE) {
+                    logger.log(Level.WARNING, "not enough data to fill read buffer from SD image file");
+                }
+                fis.close();
+            } catch (IOException ex) {
+                logger.log(Level.WARNING, "could not fill read buffer from SD image file", ex);
+            }
+        }
+    }
+
+    private void prepareWrite() {
+        this.status = Status.WRITE;
+        this.writePosition = 0;
+        computePosition();
+    }
+
+
+    private int readData() {
+        if (status != Status.READ) {
+            return 0;
+        }
+
+        int data = readBuffer[readPosition++];
+
+        if (readPosition >= SECTOR_SIZE) {
+            this.status = Status.IDLE;
+        }
+
+        return data;
+    }
+
+    private void writeData(int data) {
+        if (status != Status.WRITE) {
+            return;
+        }
+
+        writeBuffer[writePosition++] = (byte) data;
+
+        if (writePosition >= SECTOR_SIZE) {
+            if (sdImageFile != null) {
+                try {
+                    RandomAccessFile raf = new RandomAccessFile(sdImageFile, "rw");
+                    raf.skipBytes(this.position);
+                    raf.write(writeBuffer, 0, writeBuffer.length);
+                    raf.close();
+                } catch (IOException ex) {
+                    logger.log(Level.WARNING, "could not write data back to SD image file!", ex);
+                }
+            }
+
+            this.status = Status.IDLE;
+        }
+
+    }
+
+    private int readStatus() {
+        switch (this.status) {
+            case IDLE:
+                return 128;
+            case READ:
+                return 224;
+            case WRITE:
+                return 160;
+            default:
+                return 0;
+        }
+    }
+
+    private void writeCommand(int data) {
+        switch (data) {
+            case 0:
+                prepareRead();
+                return;
+            case 1:
+                prepareWrite();
+                return;
+            default:
+                this.status = Status.IDLE;
+        }
+    }
+
+    @Override
+    public String toString() {
+        return getName() + "@" + String.format("%04X", this.getMemoryRange().startAddress);
+    }
+
+}
@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+package com.loomcom.symon.devices;
+
+import com.loomcom.symon.exceptions.MemoryAccessException;
+import com.loomcom.symon.exceptions.MemoryRangeException;
+
+/**
+ * Very basic implementation of a MOS 6522 VIA.
+ *
+ * TODO: Implement timers as threads.
+ */
+public class Via6522 extends Pia {
+    public static final int VIA_SIZE = 16;
+
+    enum Register {
+        ORB, ORA, DDRB, DDRA, T1C_L, T1C_H, T1L_L, T1L_H,
+        T2C_L, T2C_H, SR, ACR, PCR, IFR, IER, ORA_H
+    }
+
+    public Via6522(int address) throws MemoryRangeException {
+        super(address, address + VIA_SIZE - 1, "MOS 6522 VIA");
+    }
+
+    @Override
+    public void write(int address, int data) throws MemoryAccessException {
+        Register[] registers = Register.values();
+
+        if (address >= registers.length) {
+            throw new MemoryAccessException("Unknown register: " + address);
+        }
+
+        Register r = registers[address];
+
+        switch (r) {
+            case ORA:
+            case ORB:
+            case DDRA:
+            case DDRB:
+            case T1C_L:
+            case T1C_H:
+            case T1L_L:
+            case T1L_H:
+            case T2C_L:
+            case T2C_H:
+            case SR:
+            case ACR:
+            case PCR:
+            case IFR:
+            case IER:
+            case ORA_H:
+            default:
+        }
+    }
+
+    @Override
+    public int read(int address, boolean cpuAccess) throws MemoryAccessException {
+        Register[] registers = Register.values();
+
+        if (address >= registers.length) {
+            throw new MemoryAccessException("Unknown register: " + address);
+        }
+
+        Register r = registers[address];
+
+        switch (r) {
+            case ORA:
+            case ORB:
+            case DDRA:
+            case DDRB:
+            case T1C_L:
+            case T1C_H:
+            case T1L_L:
+            case T1L_H:
+            case T2C_L:
+            case T2C_H:
+            case SR:
+            case ACR:
+            case PCR:
+            case IFR:
+            case IER:
+            case ORA_H:
+            default:
+        }
+
+        return 0;
+    }
+}
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008-2013 Seth J. Morabito <sethm@loomcom.com>
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008-2013 Seth J. Morabito <sethm@loomcom.com>
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008-2013 Seth J. Morabito <sethm@loomcom.com>
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008-2013 Seth J. Morabito <sethm@loomcom.com>
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
@@ -31,7 +31,4 @@ public class SymonException extends Exception {
    public SymonException(String msg) {
        super(msg);
    }
-    public SymonException() {
-        super();
-    }
 }
@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2009-2011 Graham Edgecombe.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+package com.loomcom.symon.jterminal;
+
+/**
+ * A {@link TerminalModel} which implements some common behaviour.
+ * @author Graham Edgecombe
+ */
+public abstract class AbstractTerminalModel implements TerminalModel {
+
+	@Override
+	public void clear() {
+		int rows = getRows(), columns = getColumns();
+		for (int column = 0; column < columns; column++) {
+			for (int row = 0; row < rows; row++) {
+				setCell(column, row, null);
+			}
+		}
+	}
+
+	@Override
+	public void moveCursorBack(int n) {
+		if (n < 0) {
+			throw new IllegalArgumentException("n must be positive");
+		}
+		int cursorColumn = getCursorColumn() - n;
+		if (cursorColumn < 0) {
+			cursorColumn = 0;
+		}
+		setCursorColumn(cursorColumn);
+	}
+
+	@Override
+	public void moveCursorForward(int n) {
+		if (n < 0) {
+			throw new IllegalArgumentException("n must be positive");
+		}
+		int columns = getColumns();
+		int cursorColumn = getCursorColumn() + n;
+		if (cursorColumn >= columns) {
+			cursorColumn = columns - 1;
+		}
+		setCursorColumn(cursorColumn);
+	}
+
+	@Override
+	public void moveCursorDown(int n) {
+		if (n < 0) {
+			throw new IllegalArgumentException("n must be positive");
+		}
+		int bufferSize = getBufferSize();
+		int cursorRow = getCursorRow() + n;
+		if (cursorRow >= bufferSize) {
+			cursorRow = bufferSize - 1;
+		}
+		setCursorRow(cursorRow);
+	}
+
+	@Override
+	public void moveCursorUp(int n) {
+		if (n < 0) {
+			throw new IllegalArgumentException("n must be positive");
+		}
+		int cursorRow = getCursorRow() - n;
+		if (cursorRow < 0) {
+			cursorRow = 0;
+		}
+		setCursorRow(cursorRow);
+	}
+
+}
+
@@ -0,0 +1,198 @@
+/*
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
+ * Portions Copyright (c) 2009-2011 Graham Edgecombe
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+package com.loomcom.symon.jterminal;
+
+import com.loomcom.symon.jterminal.vt100.Vt100TerminalModel;
+import java.awt.BorderLayout;
+import java.awt.Dimension;
+import java.awt.Font;
+import java.awt.FontMetrics;
+import java.awt.Graphics;
+import java.awt.event.AdjustmentEvent;
+import java.awt.event.AdjustmentListener;
+import javax.swing.JComponent;
+import javax.swing.JScrollBar;
+
+/**
+ * Swing terminal emulation component
+ * @author Seth J. Morabito
+ *
+ */
+public class JTerminal extends JComponent {
+
+	private static final long serialVersionUID = 2871625194146986567L;
+
+	private int borderWidth = 0;
+
+	private JScrollBar scrollBar;
+
+	/**
+	 * The terminal emulation model
+	 */
+	private TerminalModel model;
+
+	/**
+	 * The font this terminal uses
+	 */
+	private Font font;
+
+	/**
+	 * The cell width in pixels
+	 */
+	private int cellWidth;
+
+	/**
+	 * The cell height in pixels
+	 */
+	private int cellHeight;
+
+	/**
+	 * Max descender for font 
+	 */
+	private int maxDescender;
+
+	public JTerminal(Font font) {
+		this(new Vt100TerminalModel(), font);
+	}
+
+	public JTerminal(TerminalModel model, Font font) {
+		setModel(model);
+		setFont(font);
+		init();
+	}
+
+	public void setBorderWidth(int borderWidth) {
+		this.borderWidth = borderWidth;
+		revalidate();
+	}
+
+	public int getBorderWidth() {
+		return borderWidth;
+	}
+
+	public void setFont(Font font) {
+		this.font = font;
+		setCellWidthAndHeight(font);
+		revalidate();
+	}
+
+	public Font getFont() {
+		return font;
+	}
+
+	public void setModel(TerminalModel model) {
+		if (model == null) {
+			throw new NullPointerException("model");
+		}
+		this.model = model;
+	}
+
+	public TerminalModel getModel() {
+		return model;
+	}
+
+	public void println(String str) {
+		if (str == null) {
+			throw new NullPointerException("str");
+		}
+		print(str.concat("\r\n"));
+	}
+
+	public void print(String str) {
+		model.print(str);
+	}
+
+	public Dimension getMinimumSize() {
+		return new Dimension(model.getColumns() * cellWidth + borderWidth * 2,
+				model.getRows() * cellHeight + borderWidth * 2);
+	}
+
+	public Dimension getMaximumSize() {
+		return getMinimumSize();
+	}
+
+	public Dimension getPreferredSize() {
+		return getMinimumSize();
+	}
+
+	public void paint(Graphics g) {
+		g.setFont(font);
+
+		int width = model.getColumns();
+		int height = model.getBufferSize();
+
+		g.setColor(model.getDefaultBackgroundColor());
+		g.fillRect(0, 0, width * cellWidth + borderWidth * 2, height * cellHeight + borderWidth * 2);
+
+		int start = scrollBar == null ? 0 : scrollBar.getValue();
+		for (int y = start; y < height; y++) {
+			for (int x = 0; x < width; x++) {
+				TerminalCell cell = model.getCell(x, y);
+				boolean cursorHere = (model.getCursorRow() == y) && (model.getCursorColumn() == x);
+
+				if ((cursorHere) && (cell == null)) {
+					cell = new TerminalCell(' ', model.getDefaultBackgroundColor(), model.getDefaultForegroundColor());
+				}
+
+				if (cell != null) {
+					int px = x * cellWidth + borderWidth;
+					int py = (y - start) * cellHeight + borderWidth;
+
+					g.setColor(cursorHere ? cell.getForegroundColor() : cell.getBackgroundColor());
+					g.fillRect(px, py, cellWidth, cellHeight);
+
+					g.setColor(cursorHere ? cell.getBackgroundColor() : cell.getForegroundColor());
+					g.drawChars(new char[] { cell.getCharacter() }, 0, 1, px, py + cellHeight - maxDescender);
+				}
+			}
+		}
+	}
+
+	private void init() {
+		setLayout(new BorderLayout(0, 0));
+
+		int rows = model.getRows();
+		int bufferSize = model.getBufferSize();
+
+		if (bufferSize > rows) {
+			scrollBar = new JScrollBar(1, 0, rows, 0, bufferSize + 1);
+			scrollBar.addAdjustmentListener(new AdjustmentListener() {
+				public void adjustmentValueChanged(AdjustmentEvent evt) {
+					repaint();
+				}
+			});
+			add("After", scrollBar);
+		}
+
+		repaint();
+	}
+
+	private void setCellWidthAndHeight(Font font) {
+		FontMetrics metrics = getFontMetrics(font);
+		cellWidth = metrics.charWidth('W');
+		cellHeight = metrics.getHeight();
+		maxDescender = metrics.getMaxDescent();
+	}
+}
@@ -0,0 +1,96 @@
+/*
+ * Copyright (c) 2009-2011 Graham Edgecombe.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+package com.loomcom.symon.jterminal;
+
+import java.awt.Color;
+
+/**
+ * Represents a single terminal cell which contains a character, background
+ * color and foreground color.
+ * @author Graham Edgecombe
+ */
+public class TerminalCell {
+
+	/**
+	 * The character.
+	 */
+	private final char character;
+
+	/**
+	 * The background color.
+	 */
+	private final Color backgroundColor;
+
+	/**
+	 * The foreground color.
+	 */
+	private final Color foregroundColor;
+
+	/**
+	 * Creates a terminal cell with the specified character, background color
+	 * and foreground color.
+	 * @param character The character.
+	 * @param backgroundColor The background color.
+	 * @param foregroundColor The foreground color.
+	 * @throws NullPointerException if the background or foreground color(s)
+	 * are {@code null}.
+	 */
+	public TerminalCell(char character, Color backgroundColor, Color foregroundColor) {
+		if (backgroundColor == null) {
+			throw new NullPointerException("backgroundColor");
+		}
+		if (foregroundColor == null) {
+			throw new NullPointerException("foregroundColor");
+		}
+
+		this.character = character;
+		this.backgroundColor = backgroundColor;
+		this.foregroundColor = foregroundColor;
+	}
+
+	/**
+	 * Gets the character.
+	 * @return The character.
+	 */
+	public char getCharacter() {
+		return character;
+	}
+
+	/**
+	 * Gets the background color.
+	 * @return The background color.
+	 */
+	public Color getBackgroundColor() {
+		return backgroundColor;
+	}
+
+	/**
+	 * Gets the foreground color.
+	 * @return The foreground color.
+	 */
+	public Color getForegroundColor() {
+		return foregroundColor;
+	}
+
+}
+
@@ -0,0 +1,167 @@
+/*
+ * Copyright (c) 2009-2011 Graham Edgecombe.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+package com.loomcom.symon.jterminal;
+
+import java.awt.Color;
+
+import com.loomcom.symon.jterminal.bell.BellStrategy;
+
+/**
+ * Model for terminals - defines methods for getting/setting cells, printing
+ * text to a terminal and getting the size of the terminal and buffer.
+ */
+public interface TerminalModel {
+
+	/**
+	 * Gets the bell strategy.
+	 * @return The bell strategy.
+	 */
+	public BellStrategy getBellStrategy();
+
+	/**
+	 * Sets the bell strategy.
+	 * @param strategy The bell strategy.
+	 * @throws NullPointerException if the strategy is {@code null}.
+	 */
+	public void setBellStrategy(BellStrategy strategy);
+
+	/**
+	 * Clears the terminal.
+	 */
+	public void clear();
+
+	/**
+	 * Moves the cursor back n characters.
+	 * @param n The number of characters.
+	 * @throws IllegalArgumentException if n is not positive.
+	 */
+	public void moveCursorBack(int n);
+
+	/**
+	 * Moves the cursor forward n characters.
+	 * @param n The number of characters.
+	 * @throws IllegalArgumentException if n is not positive.
+	 */
+	public void moveCursorForward(int n);
+
+	/**
+	 * Moves the cursor down n characters.
+	 * @param n The number of characters.
+	 * @throws IllegalArgumentException if n is not positive.
+	 */
+	public void moveCursorDown(int n);
+
+	/**
+	 * Moves the cursor up n characters.
+	 * @param n The number of characters.
+	 * @throws IllegalArgumentException if n is not positive.
+	 */
+	public void moveCursorUp(int n);
+
+	/**
+	 * Sets a cell.
+	 * @param column The column.
+	 * @param row The row.
+	 * @param cell The cell.
+	 * @throws IndexOutOfBoundsException if the column and/or row number(s) are
+	 * out of bounds.
+	 */
+	public void setCell(int column, int row, TerminalCell cell);
+
+	/**
+	 * Gets a cell.
+	 * @param column The column.
+	 * @param row The row.
+	 * @return The cell.
+	 * @throws IndexOutOfBoundsException if the column and/or row number(s) are
+	 * out of bounds.
+	 */
+	public TerminalCell getCell(int column, int row);
+
+	/**
+	 * Prints the specified string to the terminal at the cursor position,
+	 * interpreting any escape sequences/special ASCII codes the model may
+	 * support. Lines will be wrapped if necessary.
+	 * @param str The string to print.
+	 * @throws NullPointerException if the string is {@code null}.
+	 */
+	public void print(String str);
+
+	/**
+	 * Gets the number of columns.
+	 * @return The number of columns.
+	 */
+	public int getColumns();
+
+	/**
+	 * Gets the number of rows.
+	 * @return The number of rows.
+	 */
+	public int getRows();
+
+	/**
+	 * Gets the buffer size.
+	 * @return The buffer size.
+	 */
+	public int getBufferSize();
+
+	/**
+	 * Gets the cursor row.
+	 * @return The cursor row.
+	 */
+	public int getCursorRow();
+
+	/**
+	 * Sets the cursor row.
+	 * @param row The cursor row.
+	 * @throws IllegalArgumentException if the row is out of the valid range.
+	 */
+	public void setCursorRow(int row);
+
+	/**
+	 * Gets the cursor column.
+	 * @return The cursor column.
+	 */
+	public int getCursorColumn();
+
+	/**
+	 * Sets the cursor column.
+	 * @param column The cursor column.
+	 * @throws IllegalArgumentException if the column is out of the valid range.
+	 */
+	public void setCursorColumn(int column);
+
+	/**
+	 * Gets the default background color.
+	 * @return The default background color.
+	 */
+	public Color getDefaultBackgroundColor();
+
+	/**
+	 * Gets the default foreground color.
+	 * @return The default foreground color.
+	 */
+	public Color getDefaultForegroundColor();
+
+}
+
@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2009-2011 Graham Edgecombe.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+package com.loomcom.symon.jterminal.bell;
+
+import java.awt.Toolkit;
+
+/**
+ * A {@link BellStrategy} which calls {@link Toolkit#beep()}.
+ * @author Graham Edgecombe
+ */
+public class BeepBellStrategy implements BellStrategy {
+
+	@Override
+	public void soundBell() {
+		Toolkit.getDefaultToolkit().beep();
+	}
+
+}
+
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2009-2011 Graham Edgecombe.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+package com.loomcom.symon.jterminal.bell;
+
+/**
+ * A 'strategy' used to sound the bell (US-ASCII character {@code 7}).
+ * @author Graham Edgecombe
+ */
+public interface BellStrategy {
+
+	/**
+	 * Sounds the bell.
+	 */
+	public void soundBell();
+
+}
+
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2009-2011 Graham Edgecombe.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+package com.loomcom.symon.jterminal.bell;
+
+/**
+ * A {@link BellStrategy} which does nothing.
+ * @author Graham Edgecombe
+ */
+public class NopBellStrategy implements BellStrategy {
+
+	@Override
+	public void soundBell() {
+		/* ignore */
+	}
+
+}
+
@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2009-2011 Graham Edgecombe.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+package com.loomcom.symon.jterminal.vt100;
+
+/**
+ * Represents an ANSI control sequence.
+ * @author Graham Edgecombe
+ */
+public class AnsiControlSequence {
+
+	/**
+	 * The command character.
+	 */
+	private final char command;
+
+	/**
+	 * The parameters.
+	 */
+	private final String[] parameters;
+
+	/**
+	 * Creates an ANSI control sequence with the specified command and
+	 * parameters.
+	 * @param command The command character.
+	 * @param parameters The parameters array.
+	 * @throws NullPointerException if the parameters array is {@code null}.
+	 */
+	public AnsiControlSequence(char command, String[] parameters) {
+		if (parameters == null) {
+			throw new NullPointerException("parameters");
+		}
+		this.command = command;
+		if (parameters.length == 1 && parameters[0].equals("")) {
+			this.parameters = new String[0];
+		} else {
+			this.parameters = parameters.clone();
+		}
+	}
+
+	/**
+	 * Gets the command character.
+	 * @return The command character.
+	 */
+	public char getCommand() {
+		return command;
+	}
+
+	/**
+	 * Gets the parameters array.
+	 * @return The parameters array.
+	 */
+	public String[] getParameters() {
+		return parameters;
+	}
+
+}
+
@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2009-2011 Graham Edgecombe.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+package com.loomcom.symon.jterminal.vt100;
+
+/**
+ * An interface which classes may use to listen to events from a
+ * {@link AnsiControlSequenceParser}.
+ */
+public interface AnsiControlSequenceListener {
+
+	/**
+	 * Called when a control sequence has been parsed.
+	 * @param seq The control sequence.
+	 */
+	public void parsedControlSequence(AnsiControlSequence seq);
+
+	/**
+	 * Called when a string has been parsed.
+	 * @param str The string.
+	 */
+	public void parsedString(String str);
+
+}
+
@@ -0,0 +1,156 @@
+/*
+ * Copyright (c) 2009-2011 Graham Edgecombe.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+package com.loomcom.symon.jterminal.vt100;
+
+import java.io.IOException;
+import java.io.Reader;
+import java.io.StringReader;
+
+/**
+ * A class which parses {@link AnsiControlSequence}s from {@link String}(s).
+ * @author Graham Edgecombe
+ */
+public class AnsiControlSequenceParser {
+
+	/**
+	 * The multi-byte control sequence introducer.
+	 */
+	private static final char[] MULTI_CSI = new char[] { 27, '[' };
+
+	/**
+	 * The single-byte control sequence introducer.
+	 */
+	private static final char SINGLE_CSI = 155;
+
+	/**
+	 * The buffer of data from the last call to {@link #parse()}. This is
+	 * populated with data if an escape sequence is not complete.
+	 */
+	private StringBuilder buffer = new StringBuilder();
+
+	/**
+	 * The ANSI control sequence listener.
+	 */
+	private final AnsiControlSequenceListener listener;
+
+	/**
+	 * Creates the ANSI control sequence parser.
+	 * @param listener The listener.
+	 */
+	public AnsiControlSequenceParser(AnsiControlSequenceListener listener) {
+		this.listener = listener;
+	}
+
+	/**
+	 * Parses the specified string.
+	 * @param str The string to parse.
+	 */
+	public void parse(String str) {
+		if (buffer.length() > 0) {
+			str = buffer.toString().concat(str);
+			buffer = new StringBuilder();
+		}
+		Reader reader = new StringReader(str);
+		try {
+			try {
+				parse(reader);
+			} finally {
+				reader.close();
+			}
+		} catch (IOException ex) {
+			/* ignore */
+		}
+	}
+
+	/**
+	 * Parses characters from the specified character reader.
+	 * @param reader The character reader.
+	 * @throws IOException if an I/O error occurs.
+	 */
+	private void parse(Reader reader) throws IOException {
+		StringBuilder text = new StringBuilder();
+		int character;
+		while ((character = reader.read()) != -1) {
+			boolean introducedControlSequence = false;
+			if (character == SINGLE_CSI) {
+				introducedControlSequence = true;
+			} else if (character == MULTI_CSI[0]) {
+				int nextCharacter = reader.read();
+				if (nextCharacter == -1) {
+					buffer.append((char) character);
+					break;
+				} else if (nextCharacter == MULTI_CSI[1]) {
+					introducedControlSequence = true;
+				} else {
+					text.append((char) character);
+					text.append((char) nextCharacter);
+				}
+			} else {
+				text.append((char) character);
+			}
+
+			if (introducedControlSequence) {
+				if (text.length() > 0) {
+					listener.parsedString(text.toString());
+					text = new StringBuilder();
+				}
+				parseControlSequence(reader);
+			}
+		}
+
+		if (text.length() > 0) {
+			listener.parsedString(text.toString());
+		}
+	}
+
+	/**
+	 * Parses a control sequence.
+	 * @param reader The character reader.
+	 * @throws IOException if an I/O error occurs.
+	 */
+	private void parseControlSequence(Reader reader) throws IOException {
+		boolean finishedSequence = false;
+		StringBuilder parameters = new StringBuilder();
+		int character;
+		while ((character = reader.read()) != -1) {
+			if ((character >= 'a' && character <= 'z') || (character >= 'A' && character <= 'Z')) {
+				String[] array = parameters.toString().split(";");
+				AnsiControlSequence seq = new AnsiControlSequence((char) character, array);
+				listener.parsedControlSequence(seq);
+
+				finishedSequence = true;
+				break;
+			} else {
+				parameters.append((char) character);
+			}
+		}
+		if (!finishedSequence) {
+			// not an ideal solution if they used the two byte CSI, but it's
+			// easier and cleaner than keeping track of it
+			buffer.append((char) SINGLE_CSI);
+			buffer.append(parameters);
+		}
+	}
+
+}
+
@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2009-2011 Graham Edgecombe.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+package com.loomcom.symon.jterminal.vt100;
+
+import java.awt.Color;
+
+/**
+ * Contains colors used by the SGR ANSI escape sequence.
+ * @author Graham Edgecombe
+ */
+final class SgrColor {
+
+	/**
+	 * An array of normal intensity colors.
+	 */
+	public static final Color[] COLOR_NORMAL = new Color[] {
+		new Color(0, 0, 0),
+		new Color(128, 0, 0),
+		new Color(0, 128, 0),
+		new Color(128, 128, 0),
+		new Color(0, 0, 128),
+		new Color(128, 0, 128),
+		new Color(0, 128, 128),
+		new Color(192, 192, 192)
+	};
+
+	/**
+	 * An array of bright intensity colors.
+	 */
+	public static final Color[] COLOR_BRIGHT = new Color[] {
+		new Color(128, 128, 128),
+		new Color(255, 0, 0),
+		new Color(0, 255, 0),
+		new Color(255, 255, 0),
+		new Color(0, 0, 255),
+		new Color(0, 0, 255),
+		new Color(255, 0, 255),
+		new Color(0, 255, 255),
+		new Color(255, 255, 255)
+	};
+
+	/**
+	 * Default private constructor to prevent instantiation.
+	 */
+	private SgrColor() {
+
+	}
+
+}
+
@@ -0,0 +1,493 @@
+/*
+ * Copyright (c) 2009-2011 Graham Edgecombe.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+package com.loomcom.symon.jterminal.vt100;
+
+import java.awt.Color;
+
+import com.loomcom.symon.jterminal.AbstractTerminalModel;
+import com.loomcom.symon.jterminal.TerminalCell;
+import com.loomcom.symon.jterminal.TerminalModel;
+import com.loomcom.symon.jterminal.bell.BellStrategy;
+import com.loomcom.symon.jterminal.bell.NopBellStrategy;
+
+/**
+ * A VT100/ANSI-compatible terminal model.
+ * @author Graham Edgecombe
+ */
+public class Vt100TerminalModel extends AbstractTerminalModel {
+
+	/**
+	 * A {@link AnsiControlSequenceListener} which modifies the
+	 * {@link TerminalModel} appropriately when an event happens.
+	 * @author Graham Edgecombe
+	 */
+	private class Vt100Listener implements AnsiControlSequenceListener {
+
+		/**
+		 * The saved cursor row.
+		 */
+		private int savedCursorRow = -1;
+
+		/**
+		 * The saved cursor column.
+		 */
+		private int savedCursorColumn = -1;
+
+		@Override
+		public void parsedControlSequence(AnsiControlSequence seq) {
+			char command = seq.getCommand();
+			String[] parameters = seq.getParameters();
+
+			switch (command) {
+			case 'A':
+			case 'B':
+			case 'C':
+			case 'D':
+				int n = 1;
+				if (parameters.length == 1) {
+					n = Integer.parseInt(parameters[0]);
+				}
+				if (command == 'A') {
+					moveCursorUp(n);
+				} else if (command == 'B') {
+					moveCursorDown(n);
+				} else if (command == 'C') {
+					moveCursorForward(n);
+				} else if (command == 'D') {
+					moveCursorBack(n);
+				}
+				break;
+			case 'E':
+			case 'F':
+				n = 1;
+				if (parameters.length == 1) {
+					n = Integer.parseInt(parameters[0]);
+				}
+				if (command == 'E') {
+					moveCursorDown(n);
+				} else if (command == 'F') {
+					moveCursorUp(n);
+				}
+				setCursorColumn(0);
+				break;
+			case 'G':
+				if (parameters.length == 1) {
+					n = Integer.parseInt(parameters[0]);
+					setCursorColumn(n - 1);
+				}
+				break;
+			case 'H':
+			case 'f':
+				if (parameters.length == 2) {
+					n = 1;
+					int m = 1;
+					if (parameters[0].length() > 0) {
+						n = Integer.parseInt(parameters[0]);
+					}
+					if (parameters[1].length() > 0) {
+						m = Integer.parseInt(parameters[1]);
+					}
+					setCursorRow(n - 1);
+					setCursorColumn(m - 1);
+				}
+				break;
+			case 'J':
+				n = 0;
+				if (parameters.length == 1) {
+					n = Integer.parseInt(parameters[0]);
+				}
+				if (n == 0) {
+					int row = cursorRow;
+					int column = cursorColumn;
+					while(row < rows) {
+						while(column < columns) {
+							cells[row][column] = null;
+							column++;
+						}
+						column = 0;
+						row++;
+					}
+				} else if (n == 1) {
+					int row = cursorRow;
+					int column = cursorColumn;
+					while(row >= 0) {
+						while(column >= 0) {
+							cells[row][column] = null;
+							column--;
+						}
+						column = columns - 1;
+						row--;
+					}
+				} else if (n == 2) {
+					clear();
+				}
+				break;
+			case 'K':
+				n = 0;
+				if (parameters.length == 1) {
+					n = Integer.parseInt(parameters[0]);
+				}
+				if (n == 0) {
+					for (int row = cursorRow; row < rows; row++) {
+						cells[row][cursorColumn] = null;
+					}
+				} else if (n == 1) {
+					for (int row = cursorRow; row >= 0; row--) {
+						cells[row][cursorColumn] = null;
+					}
+				} else if (n == 2) {
+					for (int column = 0; column < columns; column++) {
+						cells[cursorRow][column] = null;
+					}
+				}
+				break;
+			case 'm':
+				if (parameters.length == 0) {
+					parameters = new String[] { "0" };
+				}
+				for (String parameter : parameters) {
+					if (parameter.equals("0")) {
+						foregroundColor = DEFAULT_FOREGROUND_COLOR;
+						backgroundColor = DEFAULT_BACKGROUND_COLOR;
+						backgroundBold = DEFAULT_BACKGROUND_BOLD;
+						foregroundBold = DEFAULT_FOREGROUND_BOLD;
+					} else if (parameter.equals("2")) {
+						backgroundBold = true;
+						foregroundBold = true;
+					} else if (parameter.equals("22")) {
+						backgroundBold = false;
+						foregroundBold = false;
+					} else if ((parameter.startsWith("3") || parameter.startsWith("4")) && parameter.length() == 2) {
+						int color = Integer.parseInt(parameter.substring(1));
+						if (parameter.startsWith("3")) {
+							foregroundColor = color;
+						} else if (parameter.startsWith("4")) {
+							backgroundColor = color;
+						}
+					}
+				}
+				break;
+			case 'u':
+				if (savedCursorColumn != -1 && savedCursorRow != -1) {
+					cursorColumn = savedCursorColumn;
+					cursorRow = savedCursorRow;
+				}
+				break;
+			case 's':
+				savedCursorColumn = cursorColumn;
+				savedCursorRow = cursorRow;
+				break;
+			}
+		}
+
+		@Override
+		public void parsedString(String str) {
+			for (char ch : str.toCharArray()) {
+				switch (ch) {
+				case '\0':
+					continue;
+				case '\r':
+					cursorColumn = 0;
+					continue;
+				case '\n':
+					cursorRow++;
+					break;
+				case '\t':
+					while ((++cursorColumn % TAB_WIDTH) != 0);
+					continue;
+				case 127:
+					if (cursorColumn > 0) {
+						cells[cursorRow][--cursorColumn] = null;
+					}
+					continue;
+				case 7:
+					bellStrategy.soundBell();
+					continue;
+				}
+
+				if (cursorColumn >= columns) {
+					cursorColumn = 0;
+					cursorRow++;
+				}
+
+				if (cursorRow >= bufferSize) {
+					for (int i = 1; i < bufferSize; i++) {
+						System.arraycopy(cells[i], 0, cells[i - 1], 0, columns);
+					}
+					for (int i = 0; i < columns; i++) {
+						cells[bufferSize - 1][i] = null;
+					}
+					cursorRow--;
+				}
+
+				Color back = backgroundBold ? SgrColor.COLOR_BRIGHT[backgroundColor] : SgrColor.COLOR_NORMAL[backgroundColor];
+				Color fore = foregroundBold ? SgrColor.COLOR_BRIGHT[foregroundColor] : SgrColor.COLOR_NORMAL[foregroundColor];
+				if (ch != '\n') {
+					cells[cursorRow][cursorColumn++] = new TerminalCell(ch, back, fore);
+				}
+			}
+		}
+
+	}
+
+	/**
+	 * The default number of columns.
+	 */
+	private static final int DEFAULT_COLUMNS = 80;
+
+	/**
+	 * The default number of rows.
+	 */
+	private static final int DEFAULT_ROWS = 25;
+
+	/**
+	 * The tab width in characters.
+	 */
+	private static final int TAB_WIDTH = 8;
+
+	/**
+	 * The default foreground bold flag.
+	 */
+	private static final boolean DEFAULT_FOREGROUND_BOLD = false;
+
+	/**
+	 * The default background bold flag.
+	 */
+	private static final boolean DEFAULT_BACKGROUND_BOLD = false;
+
+	/**
+	 * The default foreground color.
+	 */
+	private static final int DEFAULT_FOREGROUND_COLOR = 7;
+
+	/**
+	 * The default background color.
+	 */
+	private static final int DEFAULT_BACKGROUND_COLOR = 0;
+
+	/**
+	 * The ANSI control sequence listener.
+	 */
+	private final AnsiControlSequenceListener listener = this.new Vt100Listener();
+
+	/**
+	 * The ANSI control sequence parser.
+	 */
+	private final AnsiControlSequenceParser parser = new AnsiControlSequenceParser(listener);
+
+	/**
+	 * The current bell strategy.
+	 */
+	private BellStrategy bellStrategy = new NopBellStrategy();
+
+	/**
+	 * The array of cells.
+	 */
+	private TerminalCell[][] cells;
+
+	/**
+	 * The number of columns.
+	 */
+	private int columns;
+
+	/**
+	 * The number of rows.
+	 */
+	private int rows;
+
+	/**
+	 * The buffer size.
+	 */
+	private int bufferSize;
+
+	/**
+	 * The cursor row.
+	 */
+	private int cursorRow = 0;
+
+	/**
+	 * The cursor column.
+	 */
+	private int cursorColumn = 0;
+
+	/**
+	 * The current foreground bold flag.
+	 */
+	private boolean foregroundBold = DEFAULT_FOREGROUND_BOLD;
+
+	/**
+	 * The current background bold flag.
+	 */
+	private boolean backgroundBold = DEFAULT_BACKGROUND_BOLD;
+
+	/**
+	 * The current foreground color.
+	 */
+	private int foregroundColor = DEFAULT_FOREGROUND_COLOR;
+
+	/**
+	 * The current background color.
+	 */
+	private int backgroundColor = DEFAULT_BACKGROUND_COLOR;
+
+	/**
+	 * Creates the terminal model with the default number of columns and rows,
+	 * and the default buffer size.
+	 */
+	public Vt100TerminalModel() {
+		this(DEFAULT_COLUMNS, DEFAULT_ROWS);
+	}
+
+	/**
+	 * Creates the terminal model with the specified number of columns and
+	 * rows. The buffer size is set to the number of rows.
+	 * @param columns The number of columns.
+	 * @param rows The number of rows.
+	 * @throws IllegalArgumentException if the number of rows or columns is
+	 * negative.
+	 */
+	public Vt100TerminalModel(int columns, int rows) {
+		this(columns, rows, rows);
+	}
+
+	/**
+	 * Creates the terminal model with the specified number of columns and rows
+	 * and the specified buffer size.
+	 * @param columns The number of columns.
+	 * @param rows The number of rows.
+	 * @param bufferSize The buffer size.
+	 * @throws IllegalArgumentException if the number of rows or columns is
+	 * negative, or if the buffer size is less than the number of rows.
+	 */
+	public Vt100TerminalModel(int columns, int rows, int bufferSize) {
+		if (columns < 0 || rows < 0 || bufferSize < 0) {
+			throw new IllegalArgumentException("Zero or positive values only allowed for columns, rows and buffer size.");
+		}
+		if (bufferSize < rows) {
+			throw new IllegalArgumentException("The buffer is too small");
+		}
+		this.columns = columns;
+		this.rows = rows;
+		this.bufferSize = bufferSize;
+		init();
+	}
+
+	/**
+	 * Initializes the terminal model.
+	 */
+	private void init() {
+		cells = new TerminalCell[bufferSize][columns];
+	}
+
+	@Override
+	public int getCursorRow() {
+		return cursorRow;
+	}
+
+	@Override
+	public void setCursorRow(int row) {
+		if (row < 0 || row >= bufferSize) {
+			throw new IllegalArgumentException("row out of range");
+		}
+		cursorRow = row;
+	}
+
+	@Override
+	public int getCursorColumn() {
+		return cursorColumn;
+	}
+
+	@Override
+	public void setCursorColumn(int column) {
+		if (column < 0 || column >= columns) {
+			throw new IllegalArgumentException("column out of range");
+		}
+		cursorColumn = column;
+	}
+
+	@Override
+	public TerminalCell getCell(int column, int row) {
+		if (column < 0 || row < 0 || column >= columns || row >= bufferSize) {
+			throw new IndexOutOfBoundsException();
+		}
+		return cells[row][column];
+	}
+
+	@Override
+	public void setCell(int column, int row, TerminalCell cell) {
+		if (column < 0 || row < 0 || column >= columns || row >= bufferSize) {
+			throw new IndexOutOfBoundsException();
+		}
+		cells[row][column] = cell;
+	}
+
+	@Override
+	public void print(String str) {
+		if (str == null) {
+			throw new NullPointerException("str");
+		}
+		parser.parse(str);
+	}
+
+	@Override
+	public int getColumns() {
+		return columns;
+	}
+
+	@Override
+	public int getRows() {
+		return rows;
+	}
+
+	@Override
+	public int getBufferSize() {
+		return bufferSize;
+	}
+
+	@Override
+	public BellStrategy getBellStrategy() {
+		return bellStrategy;
+	}
+
+	@Override
+	public void setBellStrategy(BellStrategy strategy) {
+		if (strategy == null) {
+			throw new NullPointerException("strategy");
+		}
+		this.bellStrategy = strategy;
+	}
+
+	@Override
+	public Color getDefaultBackgroundColor() {
+		final int bg = DEFAULT_BACKGROUND_COLOR;
+		return DEFAULT_BACKGROUND_BOLD ? SgrColor.COLOR_BRIGHT[bg] : SgrColor.COLOR_NORMAL[bg];
+	}
+
+	@Override
+	public Color getDefaultForegroundColor() {
+		final int fg = DEFAULT_FOREGROUND_COLOR;
+		return DEFAULT_FOREGROUND_BOLD ? SgrColor.COLOR_BRIGHT[fg] : SgrColor.COLOR_NORMAL[fg];
+	}
+
+}
+
@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
+ *                    Maik Merten <maikmerten@googlemail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+package com.loomcom.symon.machines;
+
+import com.loomcom.symon.Bus;
+import com.loomcom.symon.Cpu;
+import com.loomcom.symon.devices.Acia;
+import com.loomcom.symon.devices.Crtc;
+import com.loomcom.symon.devices.Memory;
+import com.loomcom.symon.devices.Pia;
+import com.loomcom.symon.exceptions.MemoryRangeException;
+
+
+public interface Machine {
+    
+    Bus getBus();
+
+    Cpu getCpu();
+    
+    Memory getRam();
+    
+    Acia getAcia();
+    
+    Pia getPia();
+    
+    Crtc getCrtc();
+    
+    Memory getRom();
+    
+    void setRom(Memory rom) throws MemoryRangeException;
+    
+    int getRomBase();
+    
+    int getRomSize();
+    
+    int getMemorySize();
+
+    String getName();
+}
@@ -0,0 +1,164 @@
+/*
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
+ *                    Maik Merten <maikmerten@googlemail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+package com.loomcom.symon.machines;
+
+import com.loomcom.symon.Bus;
+import com.loomcom.symon.Cpu;
+import com.loomcom.symon.devices.Acia;
+import com.loomcom.symon.devices.Acia6850;
+import com.loomcom.symon.devices.Crtc;
+import com.loomcom.symon.devices.Memory;
+import com.loomcom.symon.devices.Pia;
+import com.loomcom.symon.devices.SdController;
+import com.loomcom.symon.exceptions.MemoryRangeException;
+import java.io.File;
+import java.util.logging.Logger;
+
+
+public class MulticompMachine implements Machine {
+    
+    private final static Logger logger = Logger.getLogger(MulticompMachine.class.getName());
+    
+    // Constants used by the simulated system. These define the memory map.
+    private static final int BUS_BOTTOM = 0x0000;
+    private static final int BUS_TOP    = 0xffff;
+
+    // 56K of RAM from $0000 - $DFFF
+    private static final int MEMORY_BASE = 0x0000;
+    private static final int MEMORY_SIZE = 0xE000;
+
+    // ACIA at $FFD0-$FFD1
+    private static final int ACIA_BASE = 0xFFD0;
+
+    // SD controller at $FFD8-$FFDF
+    private static final int SD_BASE = 0xFFD8;
+
+    // 8KB ROM at $E000-$FFFF
+    private static final int ROM_BASE = 0xE000;
+    private static final int ROM_SIZE = 0x2000;
+
+
+        // The simulated peripherals
+    private final Bus    bus;
+    private final Cpu    cpu;
+    private final Acia   acia;
+    private final Memory ram;
+    private       Memory rom;
+
+
+    public MulticompMachine(String romFile) throws Exception {
+        this.bus = new Bus(BUS_BOTTOM, BUS_TOP);
+        this.cpu = new Cpu();
+        this.ram = new Memory(MEMORY_BASE, MEMORY_BASE + MEMORY_SIZE - 1, false);
+        this.acia = new Acia6850(ACIA_BASE);
+        this.acia.setBaudRate(0);
+
+        bus.addCpu(cpu);
+        bus.addDevice(ram);
+        bus.addDevice(acia, 1);
+        bus.addDevice(new SdController(SD_BASE), 1);
+
+        if (romFile != null) {
+            File romImage = new File("rom.bin");
+            if (romImage.canRead()) {
+                logger.info("Loading ROM image from file " + romImage);
+                this.rom = Memory.makeROM(ROM_BASE, ROM_BASE + ROM_SIZE - 1, romImage);
+            } else {
+                logger.info("Default ROM file " + romImage +
+                        " not found, loading empty R/W memory image.");
+                this.rom = Memory.makeRAM(ROM_BASE, ROM_BASE + ROM_SIZE - 1);
+            }
+        } else {
+            logger.info("No ROM file specified, loading empty R/W memory image.");
+            this.rom = Memory.makeRAM(ROM_BASE, ROM_BASE + ROM_SIZE - 1);
+        }
+
+        bus.addDevice(rom);
+    }
+
+    @Override
+    public Bus getBus() {
+        return bus;
+    }
+
+    @Override
+    public Cpu getCpu() {
+        return cpu;
+    }
+
+    @Override
+    public Memory getRam() {
+        return ram;
+    }
+
+    @Override
+    public Acia getAcia() {
+        return acia;
+    }
+
+    @Override
+    public Pia getPia() {
+        return null;
+    }
+
+    @Override
+    public Crtc getCrtc() {
+        return null;
+    }
+
+    @Override
+    public Memory getRom() {
+        return rom;
+    }
+    
+    public void setRom(Memory rom) throws MemoryRangeException {
+        if(this.rom != null) {
+            bus.removeDevice(this.rom);
+        }
+        this.rom = rom;
+        bus.addDevice(this.rom);
+    }
+
+    @Override
+    public int getRomBase() {
+        return ROM_BASE;
+    }
+
+    @Override
+    public int getRomSize() {
+        return ROM_SIZE;
+    }
+
+    @Override
+    public int getMemorySize() {
+        return MEMORY_SIZE;
+    }
+
+    @Override
+    public String getName() {
+        return "Multicomp";
+    }
+
+}
@@ -0,0 +1,117 @@
+/*
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
+ *                    Maik Merten <maikmerten@googlemail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+package com.loomcom.symon.machines;
+
+import com.loomcom.symon.Bus;
+import com.loomcom.symon.Cpu;
+import com.loomcom.symon.devices.Acia;
+import com.loomcom.symon.devices.Crtc;
+import com.loomcom.symon.devices.Memory;
+import com.loomcom.symon.devices.Pia;
+import com.loomcom.symon.exceptions.MemoryRangeException;
+
+/**
+ * A SimpleMachine is the simplest 6502 implementation possible - it
+ * consists solely of RAM and a CPU. This machine is primarily useful
+ * for running 6502 functional tests or debugging by hand.
+ */
+public class SimpleMachine implements Machine {
+
+    private static final int BUS_BOTTOM = 0x0000;
+    private static final int BUS_TOP    = 0xffff;
+
+    private final Bus bus;
+    private final Memory ram;
+    private final Cpu cpu;
+
+    public SimpleMachine(String romFile) throws MemoryRangeException {
+        this.bus = new Bus(BUS_BOTTOM, BUS_TOP);
+        this.ram = new Memory(BUS_BOTTOM, BUS_TOP, false);
+        this.cpu = new Cpu();
+
+        bus.addCpu(cpu);
+        bus.addDevice(ram);
+    }
+
+    @Override
+    public Bus getBus() {
+        return bus;
+    }
+
+    @Override
+    public Cpu getCpu() {
+        return cpu;
+    }
+
+    @Override
+    public Memory getRam() {
+        return ram;
+    }
+
+    @Override
+    public Acia getAcia() {
+        return null;
+    }
+
+    @Override
+    public Pia getPia() {
+        return null;
+    }
+
+    @Override
+    public Crtc getCrtc() {
+        return null;
+    }
+
+    @Override
+    public Memory getRom() {
+        return null;
+    }
+
+    @Override
+    public void setRom(Memory rom) throws MemoryRangeException {
+        // No-op
+    }
+
+    @Override
+    public int getRomBase() {
+        return 0;
+    }
+
+    @Override
+    public int getRomSize() {
+        return 0;
+    }
+
+    @Override
+    public int getMemorySize() {
+        return BUS_TOP + 1;
+    }
+
+    @Override
+    public String getName() {
+        return "Simple";
+    }
+}
@@ -0,0 +1,169 @@
+/*
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
+ *                    Maik Merten <maikmerten@googlemail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+package com.loomcom.symon.machines;
+
+import com.loomcom.symon.Bus;
+import com.loomcom.symon.Cpu;
+import com.loomcom.symon.devices.*;
+import com.loomcom.symon.exceptions.MemoryRangeException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.File;
+
+public class SymonMachine implements Machine {
+    
+    private final static Logger logger = LoggerFactory.getLogger(SymonMachine.class.getName());
+    
+    // Constants used by the simulated system. These define the memory map.
+    private static final int BUS_BOTTOM = 0x0000;
+    private static final int BUS_TOP    = 0xffff;
+
+    // 32K of RAM from $0000 - $7FFF
+    private static final int MEMORY_BASE = 0x0000;
+    private static final int MEMORY_SIZE = 0x8000;
+
+    // PIA at $8000-$800F
+
+    private static final int PIA_BASE = 0x8000;
+
+    // ACIA at $8800-$8803
+    private static final int ACIA_BASE = 0x8800;
+
+    // CRTC at $9000-$9001
+    private static final int CRTC_BASE = 0x9000;
+
+    // 16KB ROM at $C000-$FFFF
+    private static final int ROM_BASE = 0xC000;
+    private static final int ROM_SIZE = 0x4000;
+
+
+        // The simulated peripherals
+    private final Bus    bus;
+    private final Cpu    cpu;
+    private final Acia   acia;
+    private final Pia    pia;
+    private final Crtc   crtc;
+    private final Memory ram;
+    private       Memory rom;
+
+
+    public SymonMachine(String romFile) throws Exception {
+        this.bus = new Bus(BUS_BOTTOM, BUS_TOP);
+        this.cpu = new Cpu();
+        this.ram = new Memory(MEMORY_BASE, MEMORY_BASE + MEMORY_SIZE - 1, false);
+        this.pia = new Via6522(PIA_BASE);
+        this.acia = new Acia6551(ACIA_BASE);
+        this.crtc = new Crtc(CRTC_BASE, ram);
+
+        bus.addCpu(cpu);
+        bus.addDevice(ram);
+        bus.addDevice(pia);
+        bus.addDevice(acia);
+        bus.addDevice(crtc);
+
+        if (romFile != null) {
+            File romImage = new File(romFile);
+            if (romImage.canRead()) {
+                logger.info("Loading ROM image from file {}", romImage);
+                this.rom = Memory.makeROM(ROM_BASE, ROM_BASE + ROM_SIZE - 1, romImage);
+            } else {
+                logger.info("Default ROM file {} not found, loading empty R/W memory image.", romImage);
+                this.rom = Memory.makeRAM(ROM_BASE, ROM_BASE + ROM_SIZE - 1);
+            }
+        } else {
+            logger.info("No ROM file specified, loading empty R/W memory image.");
+            this.rom = Memory.makeRAM(ROM_BASE, ROM_BASE + ROM_SIZE - 1);
+        }
+
+        bus.addDevice(rom);
+        
+    }
+
+    @Override
+    public Bus getBus() {
+        return bus;
+    }
+
+    @Override
+    public Cpu getCpu() {
+        return cpu;
+    }
+
+    @Override
+    public Memory getRam() {
+        return ram;
+    }
+
+    @Override
+    public Acia getAcia() {
+        return acia;
+    }
+
+    @Override
+    public Pia getPia() {
+        return pia;
+    }
+
+    @Override
+    public Crtc getCrtc() {
+        return crtc;
+    }
+
+    @Override
+    public Memory getRom() {
+        return rom;
+    }
+    
+    public void setRom(Memory rom) throws MemoryRangeException {
+        if(this.rom != null) {
+            bus.removeDevice(this.rom);
+        }
+        this.rom = rom;
+        bus.addDevice(this.rom);
+    }
+
+    @Override
+    public int getRomBase() {
+        return ROM_BASE;
+    }
+
+    @Override
+    public int getRomSize() {
+        return ROM_SIZE;
+    }
+
+    @Override
+    public int getMemorySize() {
+        return MEMORY_SIZE;
+    }
+
+    @Override
+    public String getName() {
+        return "Symon";
+    }
+
+
+}
@@ -0,0 +1,152 @@
+/*
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+package com.loomcom.symon.ui;
+
+import com.loomcom.symon.Breakpoints;
+import com.loomcom.symon.util.Utils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import javax.swing.*;
+import javax.swing.border.EmptyBorder;
+import javax.swing.event.ListSelectionEvent;
+import javax.swing.event.ListSelectionListener;
+import java.awt.*;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+
+/**
+ * Simple window to enter breakpoints.
+ */
+public class BreakpointsWindow extends JFrame {
+
+    private static final Logger logger = LoggerFactory.getLogger(BreakpointsWindow.class);
+
+    private static final Dimension FRAME_SIZE = new Dimension(240, 280);
+    private static final String EMPTY_STRING = "";
+
+    private JFrame mainWindow;
+    private Breakpoints breakpoints;
+
+    public BreakpointsWindow(Breakpoints breakpoints,
+                             JFrame mainWindow) {
+        this.breakpoints = breakpoints;
+        this.mainWindow = mainWindow;
+        createUi();
+    }
+
+    private void createUi() {
+        setTitle("Breakpoints");
+
+        JPanel breakpointsPanel = new JPanel();
+        JPanel controlPanel = new JPanel();
+
+        breakpointsPanel.setLayout(new BorderLayout());
+        breakpointsPanel.setBorder(new EmptyBorder(10, 10, 10, 10));
+
+        final JButton addButton = new JButton("Add");
+        final JButton removeButton = new JButton("Del");
+        removeButton.setEnabled(false);
+
+        final JTextField addTextField = new JTextField(4);
+
+        final JTable breakpointsTable = new JTable(breakpoints);
+        breakpointsTable.setShowGrid(true);
+        breakpointsTable.setGridColor(Color.LIGHT_GRAY);
+        breakpointsTable.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
+        breakpointsTable.getSelectionModel().addListSelectionListener(new ListSelectionListener() {
+            @Override
+            public void valueChanged(ListSelectionEvent e) {
+                if (e.getFirstIndex() > -1) {
+                    removeButton.setEnabled(true);
+                } else {
+                    removeButton.setEnabled(false);
+                }
+            }
+        });
+
+        JScrollPane scrollPane = new JScrollPane(breakpointsTable);
+        scrollPane.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
+        scrollPane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
+
+        breakpointsPanel.add(scrollPane, BorderLayout.CENTER);
+
+        ActionListener addBreakpointListener = new ActionListener() {
+            @Override
+            public void actionPerformed(ActionEvent e) {
+                int value;
+
+                String newBreakpoint = addTextField.getText();
+
+                if (newBreakpoint == null || newBreakpoint.isEmpty()) {
+                    return;
+                }
+
+                try {
+                    value = (Integer.parseInt(addTextField.getText(), 16) & 0xffff);
+                } catch (NumberFormatException ex) {
+                    logger.warn("Can't parse page number {}", newBreakpoint);
+                    return;
+                }
+
+                if (value < 0) {
+                    return;
+                }
+
+                breakpoints.addBreakpoint(value);
+
+                logger.debug("Added breakpoint ${}", Utils.wordToHex(value));
+
+                addTextField.setText(EMPTY_STRING);
+            }
+        };
+
+        addButton.addActionListener(addBreakpointListener);
+        addTextField.addActionListener(addBreakpointListener);
+
+        removeButton.addActionListener(new ActionListener() {
+            @Override
+            public void actionPerformed(ActionEvent e) {
+                breakpoints.removeBreakpointAtIndex(breakpointsTable.getSelectedRow());
+            }
+        });
+
+        controlPanel.add(addTextField);
+        controlPanel.add(addButton);
+        controlPanel.add(removeButton);
+
+        setLayout(new BorderLayout());
+        getContentPane().add(breakpointsPanel, BorderLayout.CENTER);
+        getContentPane().add(controlPanel, BorderLayout.SOUTH);
+
+        setMinimumSize(FRAME_SIZE);
+        setMaximumSize(FRAME_SIZE);
+        setPreferredSize(FRAME_SIZE);
+
+        setLocationRelativeTo(mainWindow);
+        setResizable(false);
+
+        pack();
+    }
+}
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013 Seth J. Morabito <web@loomcom.com>
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
@@ -23,8 +23,8 @@

 package com.loomcom.symon.ui;

-import com.grahamedgecombe.jterminal.JTerminal;
-import com.grahamedgecombe.jterminal.vt100.Vt100TerminalModel;
+import com.loomcom.symon.jterminal.JTerminal;
+import com.loomcom.symon.jterminal.vt100.Vt100TerminalModel;
 import com.loomcom.symon.exceptions.FifoUnderrunException;
 import com.loomcom.symon.util.FifoRingBuffer;

@@ -44,21 +44,23 @@ import java.awt.event.MouseListener;

 public class Console extends JTerminal implements KeyListener, MouseListener {

-    private static final int     DEFAULT_COLUMNS      = 80;
-    private static final int     DEFAULT_ROWS         = 24;
-    private static final int     DEFAULT_BORDER_WIDTH = 10;
+	private static final long serialVersionUID = 6633818486963338126L;
+	
+	private static final int     DEFAULT_BORDER_WIDTH = 10;
    // If true, swap CR and LF characters.
    private static final boolean SWAP_CR_AND_LF       = true;
-    // If true, send CRLF (0x0d 0x0a) whenever CR is typed
-    private static final boolean SEND_CR_LF_FOR_CR    = false;

+    // If true, send CRLF (0x0d 0x0a) whenever CR is typed
+    private boolean sendCrForLf;
    private FifoRingBuffer<Character> typeAheadBuffer;

-    public Console(int columns, int rows, Font font) {
+    public Console(int columns, int rows, Font font, boolean sendCrForLf) {
        super(new Vt100TerminalModel(columns, rows), font);
+    		//super(new Vt100TerminalModel(columns, rows));
        // A small type-ahead buffer, as might be found in any real
        // VT100-style serial terminal.
-        this.typeAheadBuffer = new FifoRingBuffer<Character>(128);
+        this.typeAheadBuffer = new FifoRingBuffer<>(128);
+        this.sendCrForLf = sendCrForLf;
        setBorderWidth(DEFAULT_BORDER_WIDTH);
        addKeyListener(this);
        addMouseListener(this);
@@ -83,7 +85,7 @@ public class Console extends JTerminal implements KeyListener, MouseListener {
    /**
     * Returns true if a key has been pressed since the last time input was read.
     *
-     * @return
+     * @return true if the type-ahead buffer has data
     */
    public boolean hasInput() {
        return !typeAheadBuffer.isEmpty();
@@ -105,7 +107,7 @@ public class Console extends JTerminal implements KeyListener, MouseListener {
            }
        }

-        if (SEND_CR_LF_FOR_CR && keyTyped == 0x0d) {
+        if (sendCrForLf && (keyTyped == 0x0d)) {
            typeAheadBuffer.push((char) 0x0d);
            typeAheadBuffer.push((char) 0x0a);
        } else {
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013 Seth J. Morabito <web@loomcom.com>
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
@@ -25,7 +25,9 @@ package com.loomcom.symon.ui;

 import com.loomcom.symon.Bus;
 import com.loomcom.symon.exceptions.MemoryAccessException;
-import com.loomcom.symon.util.HexUtil;
+import com.loomcom.symon.util.Utils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;

 import javax.swing.*;
 import javax.swing.border.EmptyBorder;
@@ -37,8 +39,7 @@ import java.awt.*;
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
 import java.util.EventObject;
-import java.util.logging.Level;
-import java.util.logging.Logger;
+

 /**
 * This Frame displays the contents of a page of memory. The page number to be displayed
@@ -46,6 +47,8 @@ import java.util.logging.Logger;
 */
 public class MemoryWindow extends JFrame implements ActionListener {

+    private static final Logger logger = LoggerFactory.getLogger(MemoryWindow.class);
+
    private MemoryTableModel memoryTableModel;
    private JTable memoryTable;
    private JTextField pageNumberTextField;
@@ -104,7 +107,7 @@ public class MemoryWindow extends JFrame implements ActionListener {

        previousPageButton.setEnabled(pageNumber > 0x00);
        nextPageButton.setEnabled(pageNumber < 0xff);
-        pageNumberTextField.setText(HexUtil.byteToHex(pageNumber));
+        pageNumberTextField.setText(Utils.byteToHex(pageNumber));
    }

    /**
@@ -190,14 +193,14 @@ public class MemoryWindow extends JFrame implements ActionListener {
            if (currentPage > 0x00) {
                setPageNumber(currentPage - 1);
                updateControls();
-                memoryTable.updateUI();
+                updateState();
            }
        } else if (e.getSource() == nextPageButton) {
            int currentPage = getPageNumber();
            if (currentPage < 0xff) {
                setPageNumber(currentPage + 1);
                updateControls();
-                memoryTable.updateUI();
+                updateState();
            }
        } else if (e.getSource() == pageNumberTextField) {
            String pageNumberInput = pageNumberTextField.getText();
@@ -205,17 +208,24 @@ public class MemoryWindow extends JFrame implements ActionListener {
                // Try to parse a hex value out of the pageNumber.
                int newPageNumber = Integer.parseInt(pageNumberInput, 16);
                setPageNumber(newPageNumber & 0xff);
-                memoryTable.updateUI();
+                updateState();
            } catch (NumberFormatException ex) {
                // An invalid number was entered. Log the error, but otherwise
                // take no action.
-                Logger.getLogger(this.getClass().getName()).log(Level.WARNING, "Can't parse page number " +
-                        pageNumberInput);
+                logger.warn("Can't parse page number {}", pageNumberInput);
            }
+
            updateControls();
        }
    }

+    /**
+     * Refresh the view of memory
+     */
+    public void updateState() {
+        memoryTable.updateUI();
+    }
+
    /**
     * A JTable that will automatically select all text in a cell
     * being edited.
@@ -318,13 +328,13 @@ public class MemoryWindow extends JFrame implements ActionListener {
        public Object getValueAt(int row, int column) {
            try {
                if (column == 0) {
-                    return HexUtil.wordToHex(fullAddress(row, 1));
+                    return Utils.wordToHex(fullAddress(row, 1));
                } else if (column < 9) {
                    // Display hex value of the data
-                    return HexUtil.byteToHex(bus.read(fullAddress(row, column)));
+                    return Utils.byteToHex(bus.read(fullAddress(row, column), false));
                } else {
                    // Display the ASCII equivalent (if printable)
-                    return HexUtil.byteToAscii(bus.read(fullAddress(row, column - 8)));
+                    return Utils.byteToAscii(bus.read(fullAddress(row, column - 8), false));
                }
            } catch (MemoryAccessException ex) {
                return "??";
@@ -339,12 +349,8 @@ public class MemoryWindow extends JFrame implements ActionListener {
                    int fullAddress = fullAddress(row, column);
                    int newValue = Integer.parseInt(hexValue, 16) & 0xff;
                    bus.write(fullAddress, newValue);
-                } catch (MemoryAccessException ex) {
-                    ;
-                } catch (NumberFormatException ex) {
-                    ;
-                } catch (ClassCastException ex) {
-                    ;
+                } catch (MemoryAccessException | NumberFormatException | ClassCastException ex) {
+                    // Intentionally swallow exception
                }
                fireTableCellUpdated(row, column);
            }
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013 Seth J. Morabito <web@loomcom.com>
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
@@ -98,19 +98,21 @@ public class PreferencesDialog extends Observable implements Preferences {
        JButton cancelButton = new JButton("Cancel");

        cancelButton.addActionListener(new ActionListener() {
+            @Override
            public void actionPerformed(ActionEvent actionEvent) {
-                updateUi();
+                PreferencesDialog.this.updateUi();
                dialog.setVisible(false);
            }
        });

        applyButton.addActionListener(new ActionListener() {
+            @Override
            public void actionPerformed(ActionEvent actionEvent) {
                haltOnBreak = haltOnBreakCheckBox.isSelected();
-                programLoadAddress = hexToInt(programLoadAddressField.getText());
-                updateUi();
+                programLoadAddress = PreferencesDialog.this.hexToInt(programLoadAddressField.getText());
+                PreferencesDialog.this.updateUi();
                // TODO: Actually check to see if values have changed, don't assume.
-                setChanged();
+                PreferencesDialog.this.setChanged();
                PreferencesDialog.this.notifyObservers();
                dialog.setVisible(false);
            }
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013 Seth J. Morabito <web@loomcom.com>
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
@@ -24,11 +24,15 @@
 package com.loomcom.symon.ui;

 import com.loomcom.symon.Cpu;
+import com.loomcom.symon.CpuState;
+import com.loomcom.symon.machines.Machine;

 import javax.swing.*;
 import javax.swing.border.Border;
 import javax.swing.border.EtchedBorder;
 import java.awt.*;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;

 /**
 * UI component that displays the current state of the simulated CPU.
@@ -50,7 +54,6 @@ public class StatusPanel extends JPanel {
    private ImageIcon negativeOn;
    private ImageIcon negativeOff;

-    private JLabel statusFlagsLabel;
    private JLabel carryFlagLabel;
    private JLabel zeroFlagLabel;
    private JLabel irqDisableFlagLabel;
@@ -66,12 +69,7 @@ public class StatusPanel extends JPanel {
    private JTextField xField;
    private JTextField yField;

-    private JLabel opcodeLabel;
-    private JLabel pcLabel;
-    private JLabel spLabel;
-    private JLabel aLabel;
-    private JLabel xLabel;
-    private JLabel yLabel;
+    private Machine machine;

    private static final int EMPTY_BORDER = 10;
    private static final Border LABEL_BORDER = BorderFactory.createEmptyBorder(0, 5, 0, 0);
@@ -79,8 +77,9 @@ public class StatusPanel extends JPanel {
    private static final Dimension LARGE_TEXT_FIELD_SIZE = new Dimension(134, 22);
    private static final Dimension SMALL_TEXT_FIELD_SIZE = new Dimension(65, 22);

-    public StatusPanel() {
+    public StatusPanel(Machine machine) {
        super();
+        this.machine = machine;
        createUi();
    }

@@ -99,20 +98,20 @@ public class StatusPanel extends JPanel {
        JPanel statusFlagsPanel = new JPanel();
        statusFlagsPanel.setAlignmentX(LEFT_ALIGNMENT);

-        carryOn = new ImageIcon(this.getClass().getResource("images/C_on.png"));
-        carryOff = new ImageIcon(this.getClass().getResource("images/C_off.png"));
-        zeroOn = new ImageIcon(this.getClass().getResource("images/Z_on.png"));
-        zeroOff = new ImageIcon(this.getClass().getResource("images/Z_off.png"));
-        irqOn = new ImageIcon(this.getClass().getResource("images/I_on.png"));
-        irqOff = new ImageIcon(this.getClass().getResource("images/I_off.png"));
-        decimalOn = new ImageIcon(this.getClass().getResource("images/D_on.png"));
-        decimalOff = new ImageIcon(this.getClass().getResource("images/D_off.png"));
-        breakOn = new ImageIcon(this.getClass().getResource("images/B_on.png"));
-        breakOff = new ImageIcon(this.getClass().getResource("images/B_off.png"));
-        overflowOn = new ImageIcon(this.getClass().getResource("images/O_on.png"));
-        overflowOff = new ImageIcon(this.getClass().getResource("images/O_off.png"));
-        negativeOn = new ImageIcon(this.getClass().getResource("images/N_on.png"));
-        negativeOff = new ImageIcon(this.getClass().getResource("images/N_off.png"));
+        carryOn = new ImageIcon(this.getClass().getResource("/C_on.png"));
+        carryOff = new ImageIcon(this.getClass().getResource("/C_off.png"));
+        zeroOn = new ImageIcon(this.getClass().getResource("/Z_on.png"));
+        zeroOff = new ImageIcon(this.getClass().getResource("/Z_off.png"));
+        irqOn = new ImageIcon(this.getClass().getResource("/I_on.png"));
+        irqOff = new ImageIcon(this.getClass().getResource("/I_off.png"));
+        decimalOn = new ImageIcon(this.getClass().getResource("/D_on.png"));
+        decimalOff = new ImageIcon(this.getClass().getResource("/D_off.png"));
+        breakOn = new ImageIcon(this.getClass().getResource("/B_on.png"));
+        breakOff = new ImageIcon(this.getClass().getResource("/B_off.png"));
+        overflowOn = new ImageIcon(this.getClass().getResource("/O_on.png"));
+        overflowOff = new ImageIcon(this.getClass().getResource("/O_off.png"));
+        negativeOn = new ImageIcon(this.getClass().getResource("/N_on.png"));
+        negativeOff = new ImageIcon(this.getClass().getResource("/N_off.png"));

        // Initialize all to off
        carryFlagLabel = new JLabel(carryOff, JLabel.CENTER);
@@ -144,25 +143,96 @@ public class StatusPanel extends JPanel {
        statusFlagsPanel.add(carryFlagLabel);

        // Create and add register and address labels
-        statusFlagsLabel = makeLabel("Flags");
-        opcodeLabel = makeLabel("IR");
-        pcLabel = makeLabel("PC");
-        spLabel = makeLabel("SP");
-        aLabel = makeLabel("A");
-        xLabel = makeLabel("X");
-        yLabel = makeLabel("Y");
+        JLabel statusFlagsLabel = makeLabel("Flags");
+        JLabel opcodeLabel = makeLabel("Next IR");
+        JLabel pcLabel = makeLabel("PC");
+        JLabel spLabel = makeLabel("SP");
+        JLabel aLabel = makeLabel("A");
+        JLabel xLabel = makeLabel("X");
+        JLabel yLabel = makeLabel("Y");

        statusFlagsLabel.setToolTipText("6502 Processor Status Flags");
        opcodeLabel.setToolTipText("Instruction Register");
        pcLabel.setToolTipText("Program Counter");
        spLabel.setToolTipText("Stack Pointer");

-        opcodeField = makeTextField(LARGE_TEXT_FIELD_SIZE);
-        pcField = makeTextField(LARGE_TEXT_FIELD_SIZE);
-        spField = makeTextField(SMALL_TEXT_FIELD_SIZE);
-        aField = makeTextField(SMALL_TEXT_FIELD_SIZE);
-        xField = makeTextField(SMALL_TEXT_FIELD_SIZE);
-        yField = makeTextField(SMALL_TEXT_FIELD_SIZE);
+        opcodeField = makeTextField(LARGE_TEXT_FIELD_SIZE, false);
+        pcField = makeTextField(LARGE_TEXT_FIELD_SIZE, true);
+        spField = makeTextField(SMALL_TEXT_FIELD_SIZE, true);
+        aField = makeTextField(SMALL_TEXT_FIELD_SIZE, true);
+        xField = makeTextField(SMALL_TEXT_FIELD_SIZE, true);
+        yField = makeTextField(SMALL_TEXT_FIELD_SIZE, true);
+
+        // Make fields editable
+        pcField.addActionListener(new ActionListener() {
+            @Override
+            public void actionPerformed(ActionEvent e) {
+                try {
+                    int newVal = StatusPanel.this.getHexVal(pcField) & 0xffff;
+                    machine.getCpu().setProgramCounter(newVal);
+                } catch (Exception ex) {
+                    // Swallow exception
+                }
+
+                StatusPanel.this.updateState();
+            }
+        });
+
+        spField.addActionListener(new ActionListener() {
+            @Override
+            public void actionPerformed(ActionEvent e) {
+                try {
+                    int newVal = StatusPanel.this.getHexVal(spField) & 0xff;
+                    machine.getCpu().setStackPointer(newVal);
+                } catch (Exception ex) {
+                    // Swallow exception
+                }
+
+                StatusPanel.this.updateState();
+            }
+        });
+
+        aField.addActionListener(new ActionListener() {
+            @Override
+            public void actionPerformed(ActionEvent e) {
+                try {
+                    int newVal = StatusPanel.this.getHexVal(aField) & 0xff;
+                    machine.getCpu().setAccumulator(newVal);
+                } catch (Exception ex) {
+                    // Swallow exception
+                }
+
+                StatusPanel.this.updateState();
+            }
+        });
+
+        xField.addActionListener(new ActionListener() {
+            @Override
+            public void actionPerformed(ActionEvent e) {
+                try {
+                    int newVal = StatusPanel.this.getHexVal(xField) & 0xff;
+                    machine.getCpu().setXRegister(newVal);
+                } catch (Exception ex) {
+                    // Swallow exception
+                }
+
+                StatusPanel.this.updateState();
+            }
+        });
+
+        yField.addActionListener(new ActionListener() {
+            @Override
+            public void actionPerformed(ActionEvent e) {
+                try {
+                    int newVal = StatusPanel.this.getHexVal(yField) & 0xff;
+                    machine.getCpu().setYRegister(newVal);
+                } catch (Exception ex) {
+                    // Swallow exception
+                }
+
+                StatusPanel.this.updateState();
+            }
+        });

        constraints.anchor = GridBagConstraints.LINE_START;
        constraints.gridwidth = 2;
@@ -220,14 +290,13 @@ public class StatusPanel extends JPanel {

    /**
     * Update the display based on the current state of the CPU.
-     *
-     * @param cpu The simulated 6502 CPU.
     */
-    public void updateState(Cpu cpu) {
-        Cpu.CpuState cpuState = cpu.getCpuState();
+    public void updateState() {
+        Cpu cpu = machine.getCpu();
+        CpuState cpuState = cpu.getCpuState();

        // Update the Processor Status Flag display
-        int status = cpu.getCpuState().getStatusFlag();
+        int status = cpuState.getStatusFlag();

        carryFlagLabel.setIcon(iconForFlag(status, 0));
        zeroFlagLabel.setIcon(iconForFlag(status, 1));
@@ -238,7 +307,9 @@ public class StatusPanel extends JPanel {
        negativeFlagLabel.setIcon(iconForFlag(status, 7));

        // Update the register and address displays
-        opcodeField.setText(cpu.getCpuState().disassembleOp());
+
+        // We always want to show the NEXT instruction that will be executed
+        opcodeField.setText(cpu.disassembleNextOp());
        pcField.setText(cpu.getProgramCounterStatus());
        spField.setText(cpu.getStackPointerStatus());
        aField.setText(cpu.getAccumulatorStatus());
@@ -313,10 +384,10 @@ public class StatusPanel extends JPanel {
        return label;
    }

-    private JTextField makeTextField(Dimension size) {
+    private JTextField makeTextField(Dimension size, boolean editable) {
        JTextField textField = new JTextField("");
        textField.setAlignmentX(LEFT_ALIGNMENT);
-        textField.setEditable(false);
+        textField.setEditable(editable);
        textField.setMinimumSize(size);
        textField.setMaximumSize(size);
        textField.setPreferredSize(size);
@@ -324,4 +395,8 @@ public class StatusPanel extends JPanel {
        return textField;
    }

+    private int getHexVal(JTextField source) throws NumberFormatException {
+        String val = source.getText().replaceAll("[^0-9a-fA-F]", "");
+        return Integer.parseInt(val, 16);
+    }
 }
@@ -1,5 +1,6 @@
 /*
- * Copyright (c) 2013 Seth J. Morabito <web@loomcom.com>
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
+ *                    Maik Merten <maikmerten@googlemail.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
@@ -23,7 +24,7 @@

 package com.loomcom.symon.ui;

-import com.loomcom.symon.Cpu;
+import com.loomcom.symon.CpuState;
 import com.loomcom.symon.util.FifoRingBuffer;

 import javax.swing.*;
@@ -35,15 +36,15 @@ import java.awt.*;
 */
 public class TraceLog extends JFrame {

-    private FifoRingBuffer<Cpu.CpuState> traceLog;
-    private JTextArea                    traceLogTextArea;
+    private final FifoRingBuffer<CpuState> traceLog;
+    private final JTextArea                    traceLogTextArea;

    private static final Dimension MIN_SIZE       = new Dimension(320, 200);
    private static final Dimension PREFERRED_SIZE = new Dimension(640, 480);
    private static final int       MAX_LOG_LENGTH = 50000;

    public TraceLog() {
-        traceLog = new FifoRingBuffer<Cpu.CpuState>(MAX_LOG_LENGTH);
+        traceLog = new FifoRingBuffer<>(MAX_LOG_LENGTH);
        setMinimumSize(MIN_SIZE);
        setPreferredSize(PREFERRED_SIZE);
        setResizable(true);
@@ -67,11 +68,15 @@ public class TraceLog extends JFrame {
     * call.
     */
    public void refresh() {
-        synchronized (this) {
-            StringBuilder logString = new StringBuilder();
-            for (Cpu.CpuState state : traceLog) {
+        StringBuilder logString = new StringBuilder();        
+        
+        synchronized(traceLog) {
+            for (CpuState state : traceLog) {
                logString.append(state.toTraceEvent());
            }
+        }
+
+        synchronized(traceLogTextArea) {
            traceLogTextArea.setText(logString.toString());
        }
    }
@@ -80,8 +85,10 @@ public class TraceLog extends JFrame {
     * Reset the log area.
     */
    public void reset() {
-        synchronized (this) {
+        synchronized(traceLog) {
            traceLog.reset();
+        }
+        synchronized(traceLogTextArea) {
            traceLogTextArea.setText("");
            traceLogTextArea.setEnabled(true);
        }
@@ -92,9 +99,9 @@ public class TraceLog extends JFrame {
     *
     * @param state The CPU State to append.
     */
-    public void append(Cpu.CpuState state) {
-        synchronized(this) {
-            traceLog.push(new Cpu.CpuState(state));
+    public void append(CpuState state) {
+        synchronized(traceLog) {
+            traceLog.push(new CpuState(state));
        }
    }

@@ -106,4 +113,8 @@ public class TraceLog extends JFrame {
        traceLogTextArea.setEnabled(true);
    }

+    public boolean shouldUpdate() {
+        return isVisible() && traceLogTextArea.isEnabled();
+    }
+
 }
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013 Seth J. Morabito <web@loomcom.com>
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
@@ -25,6 +25,7 @@ package com.loomcom.symon.ui;

 import com.loomcom.symon.devices.Crtc;
 import com.loomcom.symon.devices.DeviceChangeListener;
+import com.loomcom.symon.exceptions.MemoryAccessException;

 import javax.swing.*;
 import java.awt.*;
@@ -36,8 +37,11 @@ import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
+import java.util.logging.Level;
 import java.util.logging.Logger;

+import static java.lang.System.*;
+
 /**
 * VideoWindow represents a graphics framebuffer backed by a 6545 CRTC.
 * Each time the window's VideoPanel is repainted, the video memory is
@@ -65,7 +69,6 @@ public class VideoWindow extends JFrame implements DeviceChangeListener {

    private BufferedImage image;
    private int[] charRom;
-    private int[] videoRam;

    private int horizontalDisplayed;
    private int verticalDisplayed;
@@ -85,17 +88,21 @@ public class VideoWindow extends JFrame implements DeviceChangeListener {
    private class VideoPanel extends JPanel {
        @Override
        public void paintComponent(Graphics g) {
-            for (int i = 0; i < crtc.getPageSize(); i++) {
-                int address = crtc.getStartAddress() + i;
-                int originX = (i % horizontalDisplayed) * CHAR_WIDTH;
-                int originY = (i / horizontalDisplayed) * scanLinesPerRow;
-                image.getRaster().setPixels(originX, originY, CHAR_WIDTH, scanLinesPerRow, getGlyph(address));
+            try {
+                for (int i = 0; i < crtc.getPageSize(); i++) {
+                    int address = crtc.getStartAddress() + i;
+                    int originX = (i % horizontalDisplayed) * CHAR_WIDTH;
+                    int originY = (i / horizontalDisplayed) * scanLinesPerRow;
+                    image.getRaster().setPixels(originX, originY, CHAR_WIDTH, scanLinesPerRow, getGlyph(address));
+                }
+                Graphics2D g2d = (Graphics2D) g;
+                if (shouldScale) {
+                    g2d.scale(scaleX, scaleY);
+                }
+                g2d.drawImage(image, 0, 0, null);
+            } catch (MemoryAccessException ex) {
+                logger.log(Level.SEVERE, "Memory Access Exception, can't paint video window! " + ex.getMessage());
            }
-            Graphics2D g2d = (Graphics2D)g;
-            if (shouldScale) {
-                g2d.scale(scaleX, scaleY);
-            }
-            g2d.drawImage(image, 0, 0, null);
        }

        @Override
@@ -116,10 +123,11 @@ public class VideoWindow extends JFrame implements DeviceChangeListener {
    private class CursorBlinker implements Runnable {
        public void run() {
            SwingUtilities.invokeLater(new Runnable() {
+                @Override
                public void run() {
                    if (cursorBlinkRate > 0) {
                        hideCursor = !hideCursor;
-                        repaint();
+                        VideoWindow.this.repaint();
                    }
                }
            });
@@ -131,8 +139,7 @@ public class VideoWindow extends JFrame implements DeviceChangeListener {

        this.scheduler = Executors.newSingleThreadScheduledExecutor();
        this.crtc = crtc;
-        this.charRom = loadCharRom("/pet.rom");
-        this.videoRam = crtc.getDmaAccess();
+        this.charRom = loadCharRom("/ascii.rom");
        this.scaleX = scaleX;
        this.scaleY = scaleY;
        this.shouldScale = (scaleX > 1 || scaleY > 1);
@@ -158,13 +165,6 @@ public class VideoWindow extends JFrame implements DeviceChangeListener {

    }

-    public void refreshDisplay() {
-        // TODO: Verify whether this is necessary. Does `repaint()' do anything if the window is not visible?
-        if (isVisible()) {
-            repaint();
-        }
-    }
-
    /**
     * Called by the CRTC on state change.
     */
@@ -239,15 +239,13 @@ public class VideoWindow extends JFrame implements DeviceChangeListener {
     * @param address The address of the character being requested.
     * @return An array of integers representing the pixel data.
     */
-    private int[] getGlyph(int address) {
-        int chr = videoRam[address];
+    private int[] getGlyph(int address) throws MemoryAccessException {
+        int chr = crtc.getCharAtAddress(address);
        int romOffset = (chr & 0xff) * (CHAR_HEIGHT * CHAR_WIDTH);
        int[] glyph = new int[CHAR_WIDTH * scanLinesPerRow];

        // Populate the character
-        for (int i = 0; i < (CHAR_WIDTH * Math.min(CHAR_HEIGHT, scanLinesPerRow)); i++) {
-            glyph[i] = charRom[romOffset + i];
-        }
+        arraycopy(charRom, romOffset, glyph, 0, CHAR_WIDTH * Math.min(CHAR_HEIGHT, scanLinesPerRow));

        // Overlay the cursor
        if (!hideCursor && crtc.isCursorEnabled() && crtc.getCursorPosition() == address) {
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008-2013 Seth J. Morabito <sethm@loomcom.com>
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
@@ -38,7 +38,7 @@ public class FifoRingBuffer<E> implements Iterable<E> {
    private int maxLength;

    public FifoRingBuffer(int maxLength) {
-        this.fifoBuffer = new LinkedList<E>();
+        this.fifoBuffer = new LinkedList<>();
        this.maxLength = maxLength;
    }

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008-2013 Seth J. Morabito <sethm@loomcom.com>
+ * Copyright (c) 2016 Seth J. Morabito <web@loomcom.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
@@ -24,24 +24,9 @@
 package com.loomcom.symon.util;

 /**
- * Hex String Utilities.
- *
- * <p/>
- *
- * But why? Java, after all, has a number of ways to convert an integer into a hex string,
- * so it may look absurd to go to the trouble of writing yet another conversion! The answer is
- * performance.
- *
- * <p/>
- *
- * The most convenient way to get a formatted hex value from an integer is with the <code>String.format</code>
- * method, but this turns out to be extremely inefficient. Formatting a million integers
- * with <code>String.format</code> takes something like 1600ms. Formatting the same number of integers
- * with <code>HexUtil</code> takes only 160ms. This is on par with <code>Integer.toHexString</code>,
- * but also gives the desired padding.
- *
+ * Various Utilities
 */
-public class HexUtil {
+public class Utils {

    static final String NON_PRINTABLE = ".";

@@ -93,6 +78,7 @@ public class HexUtil {

    /**
     * Very fast 8-bit int to ASCII conversion.
+     *
     * @param val The value of an ASCII character.
     * @return A string representing the ASCII character.
     */
@@ -121,9 +107,13 @@ public class HexUtil {
     * @return Four digit, zero padded hexadecimal string.
     */
    public static String wordToHex(int val) {
-        StringBuilder sb = new StringBuilder(4);
-        sb.append(HEX_CONSTANTS[(val >> 8) & 0xff]);
-        sb.append(HEX_CONSTANTS[val & 0xff]);
-        return sb.toString();
+        return HEX_CONSTANTS[(val >> 8) & 0xff] + HEX_CONSTANTS[val & 0xff];
+    }
+
+    /**
+     * Given two bytes, return an address.
+     */
+    public static int address(int lowByte, int hiByte) {
+        return ((hiByte << 8) | lowByte) & 0xffff;
    }
 }
@@ -0,0 +1,253 @@
+package com.loomcom.symon;
+
+import com.loomcom.symon.devices.Acia;
+import com.loomcom.symon.devices.Acia6850;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.mockito.Mockito.*;
+
+public class Acia6850Test {
+    
+    private final static int CMD_STAT_REG = 0;
+    private final static int DATA_REG = 1;
+    
+    
+    private Acia newAcia() throws Exception {
+        Acia acia = new Acia6850(0x0000);
+        // by default rate is limited, have it unlimited for testing
+        acia.setBaudRate(0);
+        return acia;
+    }
+    
+
+    @Test
+    public void shouldTriggerInterruptOnRxFullIfRxIrqEnabled() throws Exception {
+        Bus mockBus = mock(Bus.class);
+
+        Acia acia = newAcia();
+        acia.setBus(mockBus);
+
+        // Disable TX IRQ, Enable RX IRQ
+        acia.write(CMD_STAT_REG, 0x80);
+
+        acia.rxWrite('a');
+
+        verify(mockBus, atLeastOnce()).assertIrq();
+    }
+
+    @Test
+    public void shouldNotTriggerInterruptOnRxFullIfRxIrqNotEnabled() throws Exception {
+        Bus mockBus = mock(Bus.class);
+
+        Acia acia = newAcia();
+        acia.setBus(mockBus);
+
+        // Disable TX IRQ, Disable RX IRQ
+        acia.write(CMD_STAT_REG, 0x00);
+
+        acia.rxWrite('a');
+
+        verify(mockBus, never()).assertIrq();
+    }
+
+    @Test
+    public void shouldTriggerInterruptOnTxEmptyIfTxIrqEnabled() throws Exception {
+        Bus mockBus = mock(Bus.class);
+
+        Acia acia = newAcia();
+        acia.setBus(mockBus);
+
+        // Enable TX IRQ, Disable RX IRQ
+        acia.write(CMD_STAT_REG, 0x20);
+
+        // Write data
+        acia.write(1, 'a');
+
+        verify(mockBus, never()).assertIrq();
+
+        // Transmission should cause IRQ
+        acia.txRead(true);
+
+        verify(mockBus, atLeastOnce()).assertIrq();
+    }
+
+    @Test
+    public void shouldNotTriggerInterruptOnTxEmptyIfTxIrqNotEnabled() throws Exception {
+        Bus mockBus = mock(Bus.class);
+
+        Acia acia = newAcia();
+        acia.setBus(mockBus);
+
+        // Disable TX IRQ, Disable RX IRQ
+        acia.write(CMD_STAT_REG, 0x02);
+
+        // Write data
+        acia.write(DATA_REG, 'a');
+
+        // Transmission should cause IRQ
+        acia.txRead(true);
+
+        verify(mockBus, never()).assertIrq();
+    }
+
+    @Test
+    public void shouldTriggerInterruptFlagOnRxFullIfRxIrqEnabled() throws Exception {
+        Bus mockBus = mock(Bus.class);
+
+        Acia acia = newAcia();
+        acia.setBus(mockBus);
+
+        // Disable TX IRQ, Enable RX IRQ
+        acia.write(CMD_STAT_REG, 0x80);
+
+        acia.rxWrite('a');
+
+        // Receive should cause IRQ flag to be set
+        assertEquals(0x80, acia.read(0x0000, true) & 0x80);
+    }
+
+    @Test
+    public void shouldNotTriggerInterruptFlagOnRxFullIfRxIrqNotEnabled() throws Exception {
+        Bus mockBus = mock(Bus.class);
+
+        Acia acia = newAcia();
+        acia.setBus(mockBus);
+
+        // Disable TX IRQ, Disable RX IRQ
+        acia.write(CMD_STAT_REG, 0x00);
+
+        acia.rxWrite('a');
+
+        // Receive should not cause IRQ flag to be set
+        assertEquals(0x00, acia.read(0x0000, true) & 0x80);
+    }
+
+    @Test
+    public void shouldTriggerInterruptFlagOnTxEmptyIfTxIrqEnabled() throws Exception {
+        Bus mockBus = mock(Bus.class);
+
+        Acia acia = newAcia();
+        acia.setBus(mockBus);
+
+        // Enable TX IRQ, Disable RX IRQ
+        acia.write(CMD_STAT_REG, 0x20);
+
+        // Write data
+        acia.write(1, 'a');
+
+        verify(mockBus, never()).assertIrq();
+
+        // Transmission should cause IRQ flag to be set
+        acia.txRead(true);
+
+        assertEquals(0x80, acia.read(0x0000, true) & 0x80);
+    }
+
+    @Test
+    public void shouldNotTriggerInterruptFlagOnTxEmptyIfTxIrqNotEnabled() throws Exception {
+        Bus mockBus = mock(Bus.class);
+
+        Acia acia = newAcia();
+        acia.setBus(mockBus);
+
+        // Disable TX IRQ, Disable RX IRQ
+        acia.write(CMD_STAT_REG, 0x02);
+
+        // Write data
+        acia.write(DATA_REG, 'a');
+
+        // Transmission should not cause IRQ flag to be set
+        acia.txRead(true);
+
+        assertEquals(0x00, acia.read(0x0000, true) & 0x80);
+    }
+
+    @Test
+    public void newAciaShouldHaveTxEmptyStatus() throws Exception {
+        Acia acia = newAcia();
+
+        assertEquals(0x02, acia.read(CMD_STAT_REG, true) & 0x02);
+    }
+
+    @Test
+    public void aciaShouldHaveTxEmptyStatusOffIfTxHasData() throws Exception {
+        Acia acia = newAcia();
+
+        acia.txWrite('a');
+        assertEquals(0x00, acia.read(CMD_STAT_REG, true) & 0x02);
+    }
+
+    @Test
+    public void aciaShouldHaveRxFullStatusOnIfRxHasData() throws Exception {
+        Acia acia = newAcia();
+
+        acia.rxWrite('a');
+       
+        assertEquals(0x01, acia.read(CMD_STAT_REG, true) & 0x01);
+    }
+
+    @Test
+    public void aciaShouldHaveTxEmptyAndRxFullStatusOffIfRxAndTxHaveData()
+            throws Exception {
+        Acia acia = newAcia();
+       
+        acia.rxWrite('a');
+        acia.txWrite('b');
+
+        assertEquals(0x01, acia.read(CMD_STAT_REG, true) & 0x03);
+    }
+    
+    @Test
+    public void aciaShouldOverrunAndReadShouldReset()
+            throws Exception {
+
+        Acia acia = newAcia();
+
+        // overrun ACIA
+        acia.rxWrite('a');
+        acia.rxWrite('b');
+
+        assertEquals(0x20, acia.read(CMD_STAT_REG, true) & 0x20);
+
+        // read should reset
+        acia.rxRead(true);
+        assertEquals(0x00, acia.read(CMD_STAT_REG, true) & 0x20);
+
+    }
+
+    @Test
+    public void aciaShouldOverrunAndMemoryWindowReadShouldNotReset()
+            throws Exception {
+        
+        Acia acia = newAcia();
+        
+        // overrun ACIA
+        acia.rxWrite('a');
+        acia.rxWrite('b');
+        
+        assertEquals(0x20, acia.read(CMD_STAT_REG, true) & 0x20);
+        
+        // memory window read should not reset
+        acia.rxRead(false);
+        assertEquals(0x20, acia.read(CMD_STAT_REG, true) & 0x20);
+        
+    }
+
+    @Test
+    public void readingBuffersShouldResetStatus()
+            throws Exception {
+        Acia acia = newAcia();
+
+        assertEquals(0x00, acia.read(CMD_STAT_REG, true) & 0x01);
+        
+        acia.rxWrite('a');
+        
+        assertEquals(0x01, acia.read(CMD_STAT_REG, true) & 0x01);
+        
+        acia.rxRead(true);
+        
+        assertEquals(0x00, acia.read(CMD_STAT_REG, true) & 0x01);
+        
+    }
+}
@@ -1,6 +1,7 @@
 package com.loomcom.symon;

 import com.loomcom.symon.devices.Acia;
+import com.loomcom.symon.devices.Acia6551;
 import org.junit.Test;

 import static org.junit.Assert.assertEquals;
@@ -12,7 +13,7 @@ public class AciaTest {
    public void shouldTriggerInterruptOnRxFullIfRxIrqEnabled() throws Exception {
        Bus mockBus = mock(Bus.class);

-        Acia acia = new Acia(0x000);
+        Acia acia = new Acia6551(0x000);
        acia.setBus(mockBus);

        // Disable TX IRQ, Enable RX IRQ
@@ -27,7 +28,7 @@ public class AciaTest {
    public void shouldNotTriggerInterruptOnRxFullIfRxIrqNotEnabled() throws Exception {
        Bus mockBus = mock(Bus.class);

-        Acia acia = new Acia(0x000);
+        Acia acia = new Acia6551(0x000);
        acia.setBus(mockBus);

        // Disable TX IRQ, Disable RX IRQ
@@ -42,7 +43,7 @@ public class AciaTest {
    public void shouldTriggerInterruptOnTxEmptyIfTxIrqEnabled() throws Exception {
        Bus mockBus = mock(Bus.class);

-        Acia acia = new Acia(0x000);
+        Acia acia = new Acia6551(0x000);
        acia.setBus(mockBus);

        // Enable TX IRQ, Disable RX IRQ
@@ -54,7 +55,7 @@ public class AciaTest {
        verify(mockBus, never()).assertIrq();

        // Transmission should cause IRQ
-        acia.txRead();
+        acia.txRead(true);

        verify(mockBus, atLeastOnce()).assertIrq();
    }
@@ -63,7 +64,7 @@ public class AciaTest {
    public void shouldNotTriggerInterruptOnTxEmptyIfTxIrqNotEnabled() throws Exception {
        Bus mockBus = mock(Bus.class);

-        Acia acia = new Acia(0x000);
+        Acia acia = new Acia6551(0x000);
        acia.setBus(mockBus);

        // Disable TX IRQ, Disable RX IRQ
@@ -72,60 +73,185 @@ public class AciaTest {
        // Write data
        acia.write(0, 'a');

-        // Transmission should cause IRQ
-        acia.txRead();
+        // Transmission should not cause IRQ
+        acia.txRead(true);

        verify(mockBus, never()).assertIrq();
    }

    @Test
-    public void newAciaShouldHaveTxEmptyStatus() throws Exception {
-        Acia acia = new Acia(0x000);
+    public void shouldTriggerInterruptFlagOnRxFullIfRxIrqEnabled() throws Exception {
+        Bus mockBus = mock(Bus.class);

-        assertEquals(0x10, acia.read(0x0001));
+        Acia acia = new Acia6551(0x000);
+        acia.setBus(mockBus);
+
+        // Disable TX IRQ, Enable RX IRQ
+        acia.write(2, 0x00);
+
+        acia.rxWrite('a');
+
+        // Receive should cause IRQ flag to be set
+        assertEquals(0x80, acia.read(0x0001, true) & 0x80);
+    }
+
+    @Test
+    public void shouldNotTriggerInterruptFlagOnRxFullIfRxIrqNotEnabled() throws Exception {
+        Bus mockBus = mock(Bus.class);
+
+        Acia acia = new Acia6551(0x000);
+        acia.setBus(mockBus);
+
+        // Disable TX IRQ, Disable RX IRQ
+        acia.write(2, 0x02);
+
+        acia.rxWrite('a');
+
+        // Receive should not cause IRQ flag to be set
+        assertEquals(0x00, acia.read(0x0001, true) & 0x80);
+    }
+
+    @Test
+    public void shouldTriggerInterruptFlagOnTxEmptyIfTxIrqEnabled() throws Exception {
+        Bus mockBus = mock(Bus.class);
+
+        Acia acia = new Acia6551(0x000);
+        acia.setBus(mockBus);
+
+        // Enable TX IRQ, Disable RX IRQ
+        acia.write(2, 0x06);
+
+        // Write data
+        acia.write(0, 'a');
+
+        verify(mockBus, never()).assertIrq();
+
+        // Transmission should cause IRQ flag to be set
+        acia.txRead(true);
+
+        assertEquals(0x80, acia.read(0x0001, true) & 0x80);
+    }
+
+    @Test
+    public void shouldNotTriggerInterruptFlagOnTxEmptyIfTxIrqNotEnabled() throws Exception {
+        Bus mockBus = mock(Bus.class);
+
+        Acia acia = new Acia6551(0x000);
+        acia.setBus(mockBus);
+
+        // Disable TX IRQ, Disable RX IRQ
+        acia.write(2, 0x02);
+
+        // Write data
+        acia.write(0, 'a');
+
+        // Transmission should not cause IRQ flag to be set
+        acia.txRead(true);
+
+        assertEquals(0x00, acia.read(0x0001, true) & 0x80);
+    }
+
+    @Test
+    public void newAciaShouldHaveTxEmptyStatus() throws Exception {
+        Acia acia = new Acia6551(0x000);
+
+        assertEquals(0x10, acia.read(0x0001, true));
    }

    @Test
    public void aciaShouldHaveTxEmptyStatusOffIfTxHasData() throws Exception {
-        Acia acia = new Acia(0x000);
+        Acia acia = new Acia6551(0x000);

        acia.txWrite('a');
-        assertEquals(0x00, acia.read(0x0001));
+        assertEquals(0x00, acia.read(0x0001, true));
    }

    @Test
    public void aciaShouldHaveRxFullStatusOffIfRxHasData() throws Exception {
-        Acia acia = new Acia(0x000);
+        Acia acia = new Acia6551(0x000);

        acia.rxWrite('a');
-        assertEquals(0x18, acia.read(0x0001));
+        assertEquals(0x18, acia.read(0x0001, true));
    }

    @Test
    public void aciaShouldHaveTxEmptyAndRxFullStatusOffIfRxAndTxHaveData()
            throws Exception {
-        Acia acia = new Acia(0x000);
+        Acia acia = new Acia6551(0x000);

        acia.rxWrite('a');
        acia.txWrite('b');

-        assertEquals(0x08, acia.read(0x0001));
+        assertEquals(0x08, acia.read(0x0001, true));
+    }
+    
+    @Test
+    public void aciaShouldOverrunAndReadShouldReset()
+            throws Exception {
+        
+        Acia acia = new Acia6551(0x0000);
+        
+        // overrun ACIA
+        acia.rxWrite('a');
+        acia.rxWrite('b');
+        
+        assertEquals(0x04, acia.read(0x0001, true) & 0x04);
+        
+        // read should reset
+        acia.rxRead(true);
+        assertEquals(0x00, acia.read(0x0001, true) & 0x04);
+        
+    }
+
+    @Test
+    public void aciaShouldOverrunAndMemoryWindowReadShouldNotReset()
+            throws Exception {
+
+        Acia acia = new Acia6551(0x0000);
+
+        // overrun ACIA
+        acia.rxWrite('a');
+        acia.rxWrite('b');
+
+        assertEquals(0x04, acia.read(0x0001, true) & 0x04);
+
+        // memory window read should not reset
+        acia.rxRead(false);
+        assertEquals(0x04, acia.read(0x0001, true) & 0x04);
+
    }

    @Test
    public void readingBuffersShouldResetStatus()
            throws Exception {
-        Acia acia = new Acia(0x0000);
+        Acia acia = new Acia6551(0x0000);

        acia.rxWrite('a');
        acia.txWrite('b');


-        assertEquals(0x08, acia.read(0x0001));
+        assertEquals(0x08, acia.read(0x0001, true));

-        assertEquals('a', acia.rxRead());
-        assertEquals('b', acia.txRead());
+        assertEquals('a', acia.rxRead(true));
+        assertEquals('b', acia.txRead(true));

-        assertEquals(0x10, acia.read(0x0001));
+        assertEquals(0x10, acia.read(0x0001, true));
+    }
+
+    @Test
+    public void A()
+            throws Exception {
+        Acia acia = new Acia6551(0x0000);
+
+        acia.rxWrite('a');
+        acia.txWrite('b');
+
+
+        assertEquals(0x08, acia.read(0x0001, true));
+
+        assertEquals('a', acia.rxRead(false));
+        assertEquals('b', acia.txRead(false));
+
+        assertEquals(0x08, acia.read(0x0001, true));
    }
 }
@@ -59,22 +59,6 @@ public class BusTest extends TestCase {
        assertEquals(2, b.getDevices().size());
    }

-    public void testOverlappingDevicesShouldFail() throws MemoryRangeException {
-        Device memory = new Memory(0x0000, 0x0100, true);
-        Device rom = new Memory(0x00ff, 0x0200, false);
-
-        Bus b = new Bus(0x0000, 0xffff);
-
-        b.addDevice(memory);
-
-        try {
-            b.addDevice(rom);
-            fail("Should have thrown a MemoryRangeException.");
-        } catch (MemoryRangeException ex) {
-            // expected
-        }
-    }
-
    public void testIsCompleteWithFirstDeviceNotStartingAtStartAddress() throws MemoryRangeException {
        Device memory = new Memory(0x00ff, 0xff00, true);

@@ -0,0 +1,125 @@
+package com.loomcom.symon;
+
+import com.loomcom.symon.devices.Memory;
+import com.loomcom.symon.exceptions.MemoryAccessException;
+import junit.framework.*;
+
+import static junit.framework.TestCase.assertFalse;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Test for Zero Page Indirect addressing mode, found on some instructions
+ * in the 65C02 and 65816
+ */
+public class Cpu65C02AbsoluteModeTest extends TestCase {
+    protected Cpu    cpu;
+    protected Bus    bus;
+    protected Memory mem;
+
+    private void makeCmosCpu() throws Exception {
+        makeCpu(InstructionTable.CpuBehavior.CMOS_6502);
+    }
+
+    private void makeNmosCpu() throws Exception {
+        makeCpu(InstructionTable.CpuBehavior.NMOS_6502);
+    }
+
+    private void makeCpu(InstructionTable.CpuBehavior behavior) throws Exception {
+        this.cpu = new Cpu(behavior);
+        this.bus = new Bus(0x0000, 0xffff);
+        this.mem = new Memory(0x0000, 0xffff);
+        bus.addCpu(cpu);
+        bus.addDevice(mem);
+
+        // Load the reset vector.
+        bus.write(0xfffc, Bus.DEFAULT_LOAD_ADDRESS & 0x00ff);
+        bus.write(0xfffd, (Bus.DEFAULT_LOAD_ADDRESS & 0xff00) >>> 8);
+
+        cpu.reset();
+    }
+
+    public void test_STZ() throws Exception {
+        makeCmosCpu();
+        bus.write(0x0010,0xff);
+
+        bus.loadProgram(0x9c, 0x10, 0x00);  // STZ Absolute
+
+        // Test STZ Absolute ($0010)
+        assertEquals(0xff, bus.read(0x0010, true));
+        cpu.step();
+        assertEquals(0x00, bus.read(0x0010, true));
+
+    }
+
+    public void test_STZRequiresCmosCpu() throws Exception {
+        makeNmosCpu();
+        bus.write(0x0010,0xff);
+
+        bus.loadProgram(0x9c, 0x10, 0x00);   // STZ Absolute
+
+        // Test STZ Absolute ($0010)
+        assertEquals(0xff, bus.read(0x0010, true));
+        cpu.step();
+        assertEquals(0xff, bus.read(0x0010, true));
+
+    }
+
+    public void test_TSB() throws Exception {
+        makeCmosCpu();
+        bus.loadProgram(0x0c, 0x10, 0x00);   // 65C02 TSB Absolute $0010
+
+        bus.write(0x10, 0x01);
+        cpu.setAccumulator(0x01);
+        cpu.step();
+        assertEquals(0x01,bus.read(0x10,true)); // 0x01 & 0x01 = 0x01
+        assertFalse(cpu.getZeroFlag());
+
+        cpu.reset();
+        cpu.setAccumulator(0x02);
+        cpu.step();
+        assertEquals(0x03,bus.read(0x0010,true));
+        assertTrue(cpu.getZeroFlag());
+
+    }
+
+    public void test_TSBRequiresCmosCpu() throws Exception {
+        makeNmosCpu();
+        bus.loadProgram(0x0c, 0x10, 0x00);   // 65C02 TSB Absolute $0010
+
+        bus.write(0x10, 0x00);
+        cpu.setAccumulator(0x01);
+        cpu.step();
+        assertEquals(0x00,bus.read(0x0010,true));
+
+    }
+
+    public void test_TRB() throws Exception {
+        makeCmosCpu();
+        bus.loadProgram(0x1c, 0x00, 0x01);   // 65C02 TRB Absolute $0010
+
+        bus.write(0x0100, 0x03);
+        cpu.setAccumulator(0x01);
+        cpu.step();
+        assertEquals(0x02,bus.read(0x0100,true));     // $03 &= ~($01) = $02
+        assertFalse(cpu.getZeroFlag());             // Z = !(A & M)
+
+        cpu.reset();
+        cpu.setAccumulator(0x01);
+        cpu.step();
+        assertEquals(0x02,bus.read(0x0100,true));    // $02 &= ~($01) = $02
+        assertTrue(cpu.getZeroFlag());               // Z = !(A & M)
+
+    }
+
+    public void test_TRBRequiresCmosCpu() throws Exception {
+        makeNmosCpu();
+        bus.loadProgram(0x1c, 0x00, 0x01);   // 65C02 TRB Absolute $0010
+
+        bus.write(0x0100, 0xff);
+        cpu.setAccumulator(0x01);
+        cpu.step();
+        assertEquals(0xff,bus.read(0x0100,true));
+
+    }
+}
@@ -0,0 +1,87 @@
+package com.loomcom.symon;
+
+import com.loomcom.symon.devices.Memory;
+import com.loomcom.symon.exceptions.MemoryAccessException;
+import junit.framework.*;
+
+import static junit.framework.TestCase.assertFalse;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Test for Zero Page Indirect addressing mode, found on some instructions
+ * in the 65C02 and 65816
+ */
+public class Cpu65C02AbsoluteXModeTest extends TestCase {
+    protected Cpu    cpu;
+    protected Bus    bus;
+    protected Memory mem;
+
+    private void makeCmosCpu() throws Exception {
+        makeCpu(InstructionTable.CpuBehavior.CMOS_6502);
+    }
+
+    private void makeNmosCpu() throws Exception {
+        makeCpu(InstructionTable.CpuBehavior.NMOS_6502);
+    }
+
+    private void makeCpu(InstructionTable.CpuBehavior behavior) throws Exception {
+        this.cpu = new Cpu(behavior);
+        this.bus = new Bus(0x0000, 0xffff);
+        this.mem = new Memory(0x0000, 0xffff);
+        bus.addCpu(cpu);
+        bus.addDevice(mem);
+
+        // Load the reset vector.
+        bus.write(0xfffc, Bus.DEFAULT_LOAD_ADDRESS & 0x00ff);
+        bus.write(0xfffd, (Bus.DEFAULT_LOAD_ADDRESS & 0xff00) >>> 8);
+
+        cpu.reset();
+    }
+
+    public void test_STZ() throws Exception {
+        makeCmosCpu();
+        bus.write(0x0011,0xff);
+
+        bus.loadProgram(0x9e, 0x10, 0x00);  // STZ Absolute,X
+
+        // Test STZ Absolute,X ($0011)
+        cpu.setXRegister(0x01);
+        assertEquals(0xff, bus.read(0x0011, true));
+        cpu.step();
+        assertEquals(0x00, bus.read(0x0011, true));
+    }
+
+    public void test_STZRequiresCmosCpu() throws Exception {
+        makeNmosCpu();
+        bus.write(0x0011,0xff);
+
+        bus.loadProgram(0x9e, 0x10, 0x00);  // STZ Absolute,X
+
+        // Test STZ Absolute,X ($0011)
+        cpu.setXRegister(0x01);
+        assertEquals(0xff, bus.read(0x0011, true));
+        cpu.step();
+        assertEquals(0xff, bus.read(0x0011, true));
+    }
+
+    public void test_JMP_Indirect_Absolute_X () throws Exception {
+        makeCmosCpu();
+        bus.write(0x304,00);
+        bus.write(0x0305,04);
+        bus.loadProgram(0x7c, 0x00, 0x03);
+        cpu.setXRegister(0x04);
+        cpu.step();
+        assertEquals(0x0400,cpu.getProgramCounter());
+    }
+
+    public void test_JMP_Indirect_Absolute_XRequiresCmosCpu () throws Exception {
+        makeNmosCpu();
+        bus.write(0x304,00);
+        bus.write(0x0305,04);
+        bus.loadProgram(0x7c, 0x00, 0x03);
+        cpu.setXRegister(0x04);
+        cpu.step();
+        assertEquals(0x0203,cpu.getProgramCounter());
+    }
+}
@@ -0,0 +1,72 @@
+package com.loomcom.symon;
+
+import com.loomcom.symon.devices.Memory;
+import com.loomcom.symon.exceptions.MemoryAccessException;
+import junit.framework.*;
+
+import static junit.framework.TestCase.assertFalse;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Test for Zero Page Indirect addressing mode, found on some instructions
+ * in the 65C02 and 65816
+ */
+public class Cpu65C02ImmediateModeTest extends TestCase {
+    protected Cpu    cpu;
+    protected Bus    bus;
+    protected Memory mem;
+
+    private void makeCmosCpu() throws Exception {
+        makeCpu(InstructionTable.CpuBehavior.CMOS_6502);
+    }
+
+    private void makeNmosCpu() throws Exception {
+        makeCpu(InstructionTable.CpuBehavior.NMOS_6502);
+    }
+
+    private void makeCpu(InstructionTable.CpuBehavior behavior) throws Exception {
+        this.cpu = new Cpu(behavior);
+        this.bus = new Bus(0x0000, 0xffff);
+        this.mem = new Memory(0x0000, 0xffff);
+        bus.addCpu(cpu);
+        bus.addDevice(mem);
+
+        // Load the reset vector.
+        bus.write(0xfffc, Bus.DEFAULT_LOAD_ADDRESS & 0x00ff);
+        bus.write(0xfffd, (Bus.DEFAULT_LOAD_ADDRESS & 0xff00) >>> 8);
+
+        cpu.reset();
+    }
+
+    public void test_BIT_Immediate() throws Exception {
+        makeCmosCpu();
+        bus.loadProgram(0x89, 0xF1); // 65C02 BIT #$01
+        cpu.setAccumulator(0x02);
+
+        cpu.step();
+        assertTrue(cpu.getZeroFlag());              // #$02 & #$F1 = 0
+        assertEquals(0x02,cpu.getAccumulator());    // Accumulator should not be modified
+        assertFalse(cpu.getNegativeFlag());         // BIT #Immediate should not set N or V Flags
+        assertFalse(cpu.getOverflowFlag());
+
+        cpu.reset();
+        cpu.setAccumulator(0x01);
+        cpu.step();
+        assertFalse(cpu.getZeroFlag());             // #$F1 & #$01 = 1
+        assertEquals(0x01,cpu.getAccumulator());
+
+    }
+
+    public void test_BIT_ImmediateRequiresCmosCpu() throws Exception {
+        makeNmosCpu();
+        bus.loadProgram(0x89, 0xF1); // 65C02 BIT #$01
+
+        cpu.step();
+        cpu.setAccumulator(0x01);
+        assertTrue(cpu.getZeroFlag());
+        assertEquals(0x01,cpu.getAccumulator());
+
+    }
+
+}
@@ -0,0 +1,252 @@
+package com.loomcom.symon;
+
+import com.loomcom.symon.devices.Memory;
+import com.loomcom.symon.exceptions.MemoryAccessException;
+import junit.framework.*;
+
+import static junit.framework.TestCase.assertFalse;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Test for Zero Page Indirect addressing mode, found on some instructions
+ * in the 65C02 and 65816
+ */
+public class Cpu65C02ImpliedModeTest extends TestCase {
+    protected Cpu    cpu;
+    protected Bus    bus;
+    protected Memory mem;
+
+    private void makeCmosCpu() throws Exception {
+        makeCpu(InstructionTable.CpuBehavior.CMOS_6502);
+    }
+
+    private void makeNmosCpu() throws Exception {
+        makeCpu(InstructionTable.CpuBehavior.NMOS_6502);
+    }
+
+    private void makeCpu(InstructionTable.CpuBehavior behavior) throws Exception {
+        this.cpu = new Cpu(behavior);
+        this.bus = new Bus(0x0000, 0xffff);
+        this.mem = new Memory(0x0000, 0xffff);
+        bus.addCpu(cpu);
+        bus.addDevice(mem);
+
+        // Load the reset vector.
+        bus.write(0xfffc, Bus.DEFAULT_LOAD_ADDRESS & 0x00ff);
+        bus.write(0xfffd, (Bus.DEFAULT_LOAD_ADDRESS & 0xff00) >>> 8);
+
+        cpu.reset();
+    }
+
+    public void test_PHX() throws Exception {
+        makeCmosCpu();
+        cpu.stackPush(0x00);
+        cpu.setXRegister(0xff);
+        bus.loadProgram(0xda);
+
+        assertEquals(cpu.stackPeek(), 0x00);
+        cpu.step();
+        assertEquals(cpu.stackPeek(), 0xff);
+
+    }
+
+    public void test_PHXRequiresCmosCpu() throws Exception {
+        makeNmosCpu();
+        cpu.stackPush(0x00);
+        cpu.setXRegister(0xff);
+        bus.loadProgram(0xda);
+
+        assertEquals(cpu.stackPeek(), 0x00);
+        cpu.step();
+        assertEquals(cpu.stackPeek(), 0x00);
+
+    }
+
+    public void test_PLX() throws Exception {
+        makeCmosCpu();
+        cpu.stackPush(0xff);
+        cpu.setXRegister(0x00);
+        bus.loadProgram(0xfa);
+
+        assertEquals(0x00, cpu.getXRegister());
+        cpu.step();
+        assertEquals(0xff, cpu.getXRegister());
+
+    }
+
+    public void test_PLXRequiresCmosCpu() throws Exception {
+        makeNmosCpu();
+        cpu.stackPush(0xff);
+        cpu.setXRegister(0x00);
+        bus.loadProgram(0xfa);
+
+        assertEquals(0x00, cpu.getXRegister());
+        cpu.step();
+        assertEquals(0x00, cpu.getXRegister());
+
+    }
+
+    public void test_PHY() throws Exception {
+        makeCmosCpu();
+        cpu.stackPush(0x00);
+        cpu.setYRegister(0xff);
+        bus.loadProgram(0x5a);
+
+        assertEquals(0x00, cpu.stackPeek());
+        cpu.step();
+        assertEquals(0xff, cpu.stackPeek());
+
+    }
+
+    public void test_PHYRequiresCmosCpu() throws Exception {
+        makeNmosCpu();
+        cpu.stackPush(0x00);
+        cpu.setYRegister(0xff);
+        bus.loadProgram(0x5a);
+
+        assertEquals(0x00, cpu.stackPeek());
+        cpu.step();
+        assertEquals(0x00, cpu.stackPeek());
+
+    }
+
+    public void test_PLY() throws Exception {
+        makeCmosCpu();
+        cpu.stackPush(0xff);
+        cpu.setYRegister(0x00);
+        bus.loadProgram(0x7a);
+
+        assertEquals(0x00, cpu.getYRegister());
+        cpu.step();
+        assertEquals(0xff, cpu.getYRegister());
+
+    }
+
+    public void test_PLYRequiresCmosCpu() throws Exception {
+        makeNmosCpu();
+        cpu.stackPush(0xff);
+        cpu.setYRegister(0x00);
+        bus.loadProgram(0x7a);
+
+        assertEquals(0x00, cpu.getYRegister());
+        cpu.step();
+        assertEquals(0x00, cpu.getYRegister());
+
+    }
+
+    public void test_INC_A() throws Exception {
+        makeCmosCpu();
+        cpu.setAccumulator(0x10);
+        bus.loadProgram(0x1a);
+
+        cpu.step();
+        assertEquals(0x11, cpu.getAccumulator());
+        assertFalse(cpu.getZeroFlag());
+        assertFalse(cpu.getNegativeFlag());
+
+        // Incrementing to 0 should set Zero Flag
+        cpu.reset();
+        cpu.setAccumulator(0xff);
+        cpu.step();
+        assertTrue(cpu.getZeroFlag());
+        assertFalse(cpu.getNegativeFlag());
+
+        // Should set Negative Flag
+        cpu.reset();
+        cpu.setAccumulator(0x7F);
+        cpu.step();
+        assertTrue(cpu.getNegativeFlag());
+        assertFalse(cpu.getZeroFlag());
+
+    }
+
+    public void test_INC_ARequiresCmosCpu() throws Exception {
+        makeNmosCpu();
+        cpu.setAccumulator(0x10);
+        bus.loadProgram(0x1a);
+
+        cpu.step();
+        assertEquals(0x10, cpu.getAccumulator());
+
+    }
+
+    public void test_DEC_A() throws Exception {
+        makeCmosCpu();
+        cpu.setAccumulator(0x10);
+        bus.loadProgram(0x3a);
+
+        cpu.step();
+        assertEquals(0x0F, cpu.getAccumulator());
+        assertFalse(cpu.getZeroFlag());
+        assertFalse(cpu.getNegativeFlag());
+
+        // Decrementing to 0 should set Zero Flag
+        cpu.reset();
+        cpu.setAccumulator(0x01);
+        cpu.step();
+        assertTrue(cpu.getZeroFlag());
+        assertFalse(cpu.getNegativeFlag());
+
+        // Should set Negative Flag
+        cpu.reset();
+        cpu.setAccumulator(0x00);
+        cpu.step();
+        assertTrue(cpu.getNegativeFlag());
+        assertFalse(cpu.getZeroFlag());
+
+    }
+
+    public void test_DEC_ARequiresCmosCpu() throws Exception {
+        makeNmosCpu();
+        cpu.setAccumulator(0x10);
+        bus.loadProgram(0x3a);
+
+        cpu.step();
+        assertEquals(0x10, cpu.getAccumulator());
+        assertFalse(cpu.getZeroFlag());
+        assertFalse(cpu.getNegativeFlag());
+
+    }
+
+    public void test_BRK_clearsDecimalModeFlag() throws Exception {
+        makeCmosCpu();
+        cpu.setDecimalModeFlag();
+        assertEquals(0x00, cpu.stackPeek());
+        assertFalse(cpu.getBreakFlag());
+        assertTrue(cpu.getDecimalModeFlag());
+        assertEquals(0x0200, cpu.getProgramCounter());
+        assertEquals(0xff, cpu.getStackPointer());
+
+        // Set the IRQ vector
+        bus.write(0xffff, 0x12);
+        bus.write(0xfffe, 0x34);
+
+        bus.loadProgram(0xea,  // NOP
+                        0xea,  // NOP
+                        0xea,  // NOP
+                        0x00,  // BRK
+                        0xea,  // NOP
+                        0xea); // NOP
+
+        cpu.step(3); // Three NOP instructions
+
+        assertEquals(0x203, cpu.getProgramCounter());
+        assertTrue(cpu.getDecimalModeFlag());
+        cpu.step(); // Triggers the BRK
+
+        // Was at PC = 0x204.  PC+1 should now be on the stack
+        assertEquals(0x02, bus.read(0x1ff, true)); // PC high byte
+        assertEquals(0x05, bus.read(0x1fe, true)); // PC low byte
+
+
+        // Interrupt vector held 0x1234, so we should be there.
+        assertEquals(0x1234, cpu.getProgramCounter());
+        assertEquals(0xfc, cpu.getStackPointer());
+
+        // B and I flags should have been set on P
+        assertTrue(cpu.getBreakFlag());
+        assertFalse(cpu.getDecimalModeFlag());
+    }
+
+}
@@ -0,0 +1,372 @@
+package com.loomcom.symon;
+
+import com.loomcom.symon.devices.Memory;
+import com.loomcom.symon.exceptions.MemoryAccessException;
+import junit.framework.*;
+
+import static junit.framework.TestCase.assertFalse;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Test for Zero Page Indirect addressing mode, found on some instructions
+ * in the 65C02 and 65816
+ */
+public class Cpu65C02ZeroPageModeTest extends TestCase {
+    protected Cpu    cpu;
+    protected Bus    bus;
+    protected Memory mem;
+
+    private void makeCmosCpu() throws Exception {
+        makeCpu(InstructionTable.CpuBehavior.CMOS_6502);
+    }
+
+    private void makeNmosCpu() throws Exception {
+        makeCpu(InstructionTable.CpuBehavior.NMOS_6502);
+    }
+
+    private void makeCpu(InstructionTable.CpuBehavior behavior) throws Exception {
+        this.cpu = new Cpu(behavior);
+        this.bus = new Bus(0x0000, 0xffff);
+        this.mem = new Memory(0x0000, 0xffff);
+        bus.addCpu(cpu);
+        bus.addDevice(mem);
+
+        // Load the reset vector.
+        bus.write(0xfffc, Bus.DEFAULT_LOAD_ADDRESS & 0x00ff);
+        bus.write(0xfffd, (Bus.DEFAULT_LOAD_ADDRESS & 0xff00) >>> 8);
+
+        cpu.reset();
+    }
+
+    public void test_STZ() throws Exception {
+        makeCmosCpu();
+        bus.write(0x0000,0xff);
+
+        bus.loadProgram(0x64,0x00);          // STZ Zero Page $00
+
+        // Test STZ Zero Page
+        assertEquals(0xff,bus.read(0x00, true));
+        cpu.step();
+        assertEquals(0x00,bus.read(0x00, true));
+    }
+
+    public void test_STZRequiresCmosCpu() throws Exception {
+        makeNmosCpu();
+        bus.write(0x0000,0xff);
+
+        bus.loadProgram(0x64,0x00);          // STZ Zero Page $00
+
+        // Test STZ Zero Page
+        assertEquals(0xff,bus.read(0x00, true));
+        cpu.step();
+        assertEquals(0xff,bus.read(0x00, true));
+
+    }
+
+    public void test_SMB() throws Exception {
+        makeCmosCpu();
+        bus.loadProgram(0x87,0x01,  // SMB0 $01
+                        0x97,0x01,  // SMB1 $01
+                        0xa7,0x01,  // SMB2 $01
+                        0xb7,0x01,  // SMB3 $01
+                        0xc7,0x01,  // SMB4 $01
+                        0xd7,0x01,  // SMB5 $01
+                        0xe7,0x01,  // SMB6 $01
+                        0xf7,0x01); // SMB7 $01
+
+        // SMB0
+        bus.write(0x01,0x00);
+        assertEquals(0x00,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(1 << 0,bus.read(0x0001, true));
+
+        // SMB1
+        bus.write(0x01,0x00);
+        assertEquals(0x00,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(1 << 1,bus.read(0x0001, true));
+
+        // SMB2
+        bus.write(0x01,0x00);
+        assertEquals(0x00,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(1 << 2,bus.read(0x0001, true));
+
+        // SMB3
+        bus.write(0x01,0x00);
+        assertEquals(0x00,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(1 << 3,bus.read(0x0001, true));
+
+        // SMB4
+        bus.write(0x01,0x00);
+        assertEquals(0x00,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(1 << 4,bus.read(0x0001, true));
+
+        // SMB5
+        bus.write(0x01,0x00);
+        assertEquals(0x00,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(1 << 5,bus.read(0x0001, true));
+
+        // SMB6
+        bus.write(0x01,0x00);
+        assertEquals(0x00,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(1 << 6,bus.read(0x0001, true));
+
+        // SMB7
+        bus.write(0x01,0x00);
+        assertEquals(0x00,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(1 << 7,bus.read(0x0001, true));
+
+    }
+
+    public void test_SMBRequiresCmosCpu() throws Exception {
+        makeNmosCpu();
+        bus.loadProgram(0x87,0x01,  // SMB0 $01
+                        0x97,0x01,  // SMB1 $01
+                        0xa7,0x01,  // SMB2 $01
+                        0xb7,0x01,  // SMB3 $01
+                        0xc7,0x01,  // SMB4 $01
+                        0xd7,0x01,  // SMB5 $01
+                        0xe7,0x01,  // SMB6 $01
+                        0xf7,0x01); // SMB7 $01
+
+        // SMB0
+        bus.write(0x01,0x00);
+        assertEquals(0x00,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0x00,bus.read(0x0001, true));
+
+        // SMB1
+        bus.write(0x01,0x00);
+        assertEquals(0x00,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0x00,bus.read(0x0001, true));
+
+        // SMB2
+        bus.write(0x01,0x00);
+        assertEquals(0x00,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0x00,bus.read(0x0001, true));
+
+        // SMB3
+        bus.write(0x01,0x00);
+        assertEquals(0x00,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0x00,bus.read(0x0001, true));
+
+        // SMB4
+        bus.write(0x01,0x00);
+        assertEquals(0x00,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0x00,bus.read(0x0001, true));
+
+        // SMB5
+        bus.write(0x01,0x00);
+        assertEquals(0x00,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0x00,bus.read(0x0001, true));
+
+        // SMB6
+        bus.write(0x01,0x00);
+        assertEquals(0x00,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0x00,bus.read(0x0001, true));
+
+        // SMB7
+        bus.write(0x01,0x00);
+        assertEquals(0x00,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0x00,bus.read(0x0001, true));
+
+    }
+
+    public void test_RMB() throws Exception {
+        makeCmosCpu();
+        bus.loadProgram(0x07,0x01,  // SMB0 $01
+                        0x17,0x01,  // SMB1 $01
+                        0x27,0x01,  // SMB2 $01
+                        0x37,0x01,  // SMB3 $01
+                        0x47,0x01,  // SMB4 $01
+                        0x57,0x01,  // SMB5 $01
+                        0x67,0x01,  // SMB6 $01
+                        0x77,0x01); // SMB7 $01
+
+        // RMB0
+        bus.write(0x01,0xff);
+        assertEquals(0xff,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0xfe,bus.read(0x0001, true));
+
+        // RMB1
+        bus.write(0x01,0xff);
+        assertEquals(0xff,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0xfd,bus.read(0x0001, true));
+
+        // RMB2
+        bus.write(0x01,0xff);
+        assertEquals(0xff,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0xfb,bus.read(0x0001, true));
+
+        // RMB3
+        bus.write(0x01,0xff);
+        assertEquals(0xff,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0xf7,bus.read(0x0001, true));
+
+        // RMB4
+        bus.write(0x01,0xff);
+        assertEquals(0xff,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0xef,bus.read(0x0001, true));
+
+        // RMB5
+        bus.write(0x01,0xff);
+        assertEquals(0xff,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0xdf,bus.read(0x0001, true));
+
+        // RMB6
+        bus.write(0x01,0xff);
+        assertEquals(0xff,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0xbf,bus.read(0x0001, true));
+
+        // RMB7
+        bus.write(0x01,0xff);
+        assertEquals(0xff,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0x7f,bus.read(0x0001, true));
+
+    }
+
+    public void test_RMBRequiresCmosCpu() throws Exception {
+        makeNmosCpu();
+        bus.loadProgram(0x07,0x01,  // SMB0 $01
+                        0x17,0x01,  // SMB1 $01
+                        0x27,0x01,  // SMB2 $01
+                        0x37,0x01,  // SMB3 $01
+                        0x47,0x01,  // SMB4 $01
+                        0x57,0x01,  // SMB5 $01
+                        0x67,0x01,  // SMB6 $01
+                        0x77,0x01); // SMB7 $01
+
+        // RMB0
+        bus.write(0x01,0xff);
+        assertEquals(0xff,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0xff,bus.read(0x0001, true));
+
+        // RMB1
+        bus.write(0x01,0xff);
+        assertEquals(0xff,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0xff,bus.read(0x0001, true));
+
+        // RMB2
+        bus.write(0x01,0xff);
+        assertEquals(0xff,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0xff,bus.read(0x0001, true));
+
+        // RMB3
+        bus.write(0x01,0xff);
+        assertEquals(0xff,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0xff,bus.read(0x0001, true));
+
+        // RMB4
+        bus.write(0x01,0xff);
+        assertEquals(0xff,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0xff,bus.read(0x0001, true));
+
+        // RMB5
+        bus.write(0x01,0xff);
+        assertEquals(0xff,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0xff,bus.read(0x0001, true));
+
+        // RMB6
+        bus.write(0x01,0xff);
+        assertEquals(0xff,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0xff,bus.read(0x0001, true));
+
+        // RMB7
+        bus.write(0x01,0xff);
+        assertEquals(0xff,bus.read(0x0001, true));
+        cpu.step();
+        assertEquals(0xff,bus.read(0x0001, true));
+
+    }
+
+    public void test_TSB() throws Exception {
+        makeCmosCpu();
+        bus.loadProgram(0x04, 0x10);        // 65C02 TSB Zero Page $10
+
+        bus.write(0x10, 0x01);
+        cpu.setAccumulator(0x03);
+        cpu.step();
+        assertEquals(0x03,bus.read(0x10,true));
+        assertFalse(cpu.getZeroFlag());
+
+        cpu.reset();
+        bus.write(0x10, 0x01);
+        cpu.setAccumulator(0x02);
+        cpu.step();
+        assertEquals(0x03,bus.read(0x10,true));
+        assertTrue(cpu.getZeroFlag());
+
+    }
+
+    public void test_TSBRequiresCmosCpu() throws Exception {
+        makeNmosCpu();
+        bus.loadProgram(0x04, 0x10);        // 65C02 TSB Zero Page $10
+
+        bus.write(0x10, 0x01);
+        cpu.setAccumulator(0x03);
+        cpu.step();
+        assertEquals(0x01,bus.read(0x10,true));
+
+    }
+
+    public void test_TRB() throws Exception {
+        makeCmosCpu();
+        cpu.reset();
+        bus.loadProgram(0x14, 0x40);        // 65C02 TRB Zero Page $40
+
+        bus.write(0x0040, 0xff);
+        cpu.setAccumulator(0x01);
+        cpu.step();
+        assertEquals(0xfe,bus.read(0x0040,true));     // $03 &= ~($01) = $02
+        assertFalse(cpu.getZeroFlag());             // Z = !(A & M)
+
+        cpu.reset();
+        cpu.setAccumulator(0x01);
+        cpu.step();
+        assertEquals(0xfe,bus.read(0x0040,true));    // $02 &= ~($01) = $02
+        assertTrue(cpu.getZeroFlag());               // Z = !(A & M)
+
+    }
+
+    public void test_TRBRequiresCmosCpu() throws Exception {
+        makeNmosCpu();
+        cpu.reset();
+        bus.loadProgram(0x14, 0x40);        // 65C02 TRB Zero Page $40
+
+        bus.write(0x0040, 0xff);
+        cpu.setAccumulator(0x01);
+        cpu.step();
+        assertEquals(0xff,bus.read(0x0040,true));     // $03 &= ~($01) = $02
+
+    }
+
+}
@@ -0,0 +1,585 @@
+package com.loomcom.symon;
+
+import com.loomcom.symon.devices.Memory;
+import com.loomcom.symon.exceptions.MemoryAccessException;
+import junit.framework.*;
+
+import static junit.framework.TestCase.assertFalse;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Test for Zero Page Indirect addressing mode, found on some instructions
+ * in the 65C02 and 65816
+ */
+public class Cpu65C02ZeroPageRelativeTest extends TestCase {
+    protected Cpu    cpu;
+    protected Bus    bus;
+    protected Memory mem;
+
+    private void makeCmosCpu() throws Exception {
+        makeCpu(InstructionTable.CpuBehavior.CMOS_6502);
+    }
+
+    private void makeNmosCpu() throws Exception {
+        makeCpu(InstructionTable.CpuBehavior.NMOS_6502);
+    }
+
+    private void makeCpu(InstructionTable.CpuBehavior behavior) throws Exception {
+        this.cpu = new Cpu(behavior);
+        this.bus = new Bus(0x0000, 0xffff);
+        this.mem = new Memory(0x0000, 0xffff);
+        bus.addCpu(cpu);
+        bus.addDevice(mem);
+
+        // Load the reset vector.
+        bus.write(0xfffc, Bus.DEFAULT_LOAD_ADDRESS & 0x00ff);
+        bus.write(0xfffd, (Bus.DEFAULT_LOAD_ADDRESS & 0xff00) >>> 8);
+
+        cpu.reset();
+    }
+    public void test_BRA() throws Exception {
+        makeCmosCpu();
+        // Positive Offset
+        bus.loadProgram(0x80, 0x05);  // 65C02 BRA $05 ; *=$0202+$05 ($0207)
+        cpu.step();
+        assertEquals(0x207, cpu.getProgramCounter());
+
+        // Negative Offset
+        cpu.reset();
+        bus.loadProgram(0x80, 0xfb);  // 65C02 BRA $fb ; *=$0202-$05 ($01fd)
+        cpu.step();
+        assertEquals(0x1fd, cpu.getProgramCounter());
+    }
+
+    public void test_BRArequiresCmosCpu() throws Exception {
+        makeNmosCpu();
+        // Should be a NOOP on NMOS and end up at $0202
+        // Positive Offset
+        bus.loadProgram(0x80, 0x05);  // BRA $05 ; *=$0202+$05 ($0207)
+        cpu.step();
+        assertEquals(0x202, cpu.getProgramCounter());
+
+        // Negative Offset
+        cpu.reset();
+        bus.loadProgram(0x80, 0xfb);  // BRA $fb ; *=$0202-$05 ($01fd)
+        cpu.step();
+        assertEquals(0x202, cpu.getProgramCounter());
+    }
+
+    public void test_BBR() throws Exception {
+        makeCmosCpu();
+
+        /* BBR0 */
+        // Positive Offset
+        cpu.reset();
+        bus.write(0x0a,0xff);
+        bus.loadProgram(0x0f, 0x0a, 0x05);  // 65C02 BBR0 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter()); // Shouldn't have branched
+
+        cpu.reset();
+        bus.write(0x0a,0xfe);
+        bus.loadProgram(0x0f, 0x0a, 0x05);  // 65C02 BBR0 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x208, cpu.getProgramCounter()); // Should have branched
+
+        // Negative Offset
+        cpu.reset();
+        bus.write(0x0a,0xfe);
+        bus.loadProgram(0x0f, 0x0a, 0xfb);  // 65C02 BBR0 $00 $fb ; *=$0203-$05 ($01fe)
+        cpu.step();
+        assertEquals(0x1fe, cpu.getProgramCounter());
+
+        /* BBR1 */
+        // Positive Offset
+        cpu.reset();
+        bus.write(0x0a,0xff);
+        bus.loadProgram(0x1f, 0x0a, 0x05);  // 65C02 BBR1 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter()); // Shouldn't have branched
+
+        cpu.reset();
+        bus.write(0x0a,0xfd);
+        bus.loadProgram(0x1f, 0x0a, 0x05);  // 65C02 BBR1 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x208, cpu.getProgramCounter()); // Should have branched
+
+        // Negative Offset
+        cpu.reset();
+        bus.write(0x0a,0xfd);
+        bus.loadProgram(0x1f, 0x0a, 0xfb);  // 65C02 BBR1 $00 $fb ; *=$0203-$05 ($01fe)
+        cpu.step();
+        assertEquals(0x1fe, cpu.getProgramCounter());
+
+        /* BBR2 */
+        // Positive Offset
+        cpu.reset();
+        bus.write(0x0a,0xff);
+        bus.loadProgram(0x2f, 0x0a, 0x05);  // 65C02 BBR2 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter()); // Shouldn't have branched
+
+        cpu.reset();
+        bus.write(0x0a,0xfb);
+        bus.loadProgram(0x2f, 0x0a, 0x05);  // 65C02 BBR2 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x208, cpu.getProgramCounter()); // Should have branched
+
+        // Negative Offset
+        cpu.reset();
+        bus.write(0x0a,0xfb);
+        bus.loadProgram(0x2f, 0x0a, 0xfb);  // 65C02 BBR2 $00 $fb ; *=$0203-$05 ($01fe)
+        cpu.step();
+        assertEquals(0x1fe, cpu.getProgramCounter());
+
+        /* BBR3 */
+        // Positive Offset
+        cpu.reset();
+        bus.write(0x0a,0xff);
+        bus.loadProgram(0x3f, 0x0a, 0x05);  // 65C02 BBR3 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter()); // Shouldn't have branched
+
+        cpu.reset();
+        bus.write(0x0a,0xf7);
+        bus.loadProgram(0x3f, 0x0a, 0x05);  // 65C02 BBR3 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x208, cpu.getProgramCounter()); // Should have branched
+
+        // Negative Offset
+        cpu.reset();
+        bus.write(0x0a,0xf7);
+        bus.loadProgram(0x3f, 0x0a, 0xfb);  // 65C02 BBR3 $00 $fb ; *=$0203-$05 ($01fe)
+        cpu.step();
+        assertEquals(0x1fe, cpu.getProgramCounter());
+
+        /* BBR4 */
+        // Positive Offset
+        cpu.reset();
+        bus.write(0x0a,0xff);
+        bus.loadProgram(0x4f, 0x0a, 0x05);  // 65C02 BBR4 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter()); // Shouldn't have branched
+
+        cpu.reset();
+        bus.write(0x0a,0xef);
+        bus.loadProgram(0x4f, 0x0a, 0x05);  // 65C02 BBR4 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x208, cpu.getProgramCounter()); // Should have branched
+
+        // Negative Offset
+        cpu.reset();
+        bus.write(0x0a,0xef);
+        bus.loadProgram(0x4f, 0x0a, 0xfb);  // 65C02 BBR4 $00 $fb ; *=$0203-$05 ($01fe)
+        cpu.step();
+        assertEquals(0x1fe, cpu.getProgramCounter());
+
+        /* BBR5 */
+        // Positive Offset
+        cpu.reset();
+        bus.write(0x0a,0xff);
+        bus.loadProgram(0x5f, 0x0a, 0x05);  // 65C02 BBR5 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter()); // Shouldn't have branched
+
+        cpu.reset();
+        bus.write(0x0a,0xdf);
+        bus.loadProgram(0x5f, 0x0a, 0x05);  // 65C02 BBR5 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x208, cpu.getProgramCounter()); // Should have branched
+
+        // Negative Offset
+        cpu.reset();
+        bus.write(0x0a,0xdf);
+        bus.loadProgram(0x5f, 0x0a, 0xfb);  // 65C02 BBR5 $00 $fb ; *=$0203-$05 ($01fe)
+        cpu.step();
+        assertEquals(0x1fe, cpu.getProgramCounter());
+
+        /* BBR6 */
+        // Positive Offset
+        cpu.reset();
+        bus.write(0x0a,0xff);
+        bus.loadProgram(0x6f, 0x0a, 0x05);  // 65C02 BBR6 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter()); // Shouldn't have branched
+
+        cpu.reset();
+        bus.write(0x0a,0xbf);
+        bus.loadProgram(0x6f, 0x0a, 0x05);  // 65C02 BBR6 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x208, cpu.getProgramCounter()); // Should have branched
+
+        // Negative Offset
+        cpu.reset();
+        bus.write(0x0a,0xbf);
+        bus.loadProgram(0x6f, 0x0a, 0xfb);  // 65C02 BBR6 $00 $fb ; *=$0203-$05 ($01fe)
+        cpu.step();
+        assertEquals(0x1fe, cpu.getProgramCounter());
+
+        /* BBR7 */
+        // Positive Offset
+        cpu.reset();
+        bus.write(0x0a,0xff);
+        bus.loadProgram(0x7f, 0x0a, 0x05);  // 65C02 BBR7 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter()); // Shouldn't have branched
+
+        cpu.reset();
+        bus.write(0x0a,0x7f);
+        bus.loadProgram(0x7f, 0x0a, 0x05);  // 65C02 BBR7 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x208, cpu.getProgramCounter()); // Should have branched
+
+        // Negative Offset
+        cpu.reset();
+        bus.write(0x0a,0x7f);
+        bus.loadProgram(0x7f, 0x0a, 0xfb);  // 65C02 BBR7 $00 $fb ; *=$0203-$05 ($01fe)
+        cpu.step();
+        assertEquals(0x1fe, cpu.getProgramCounter());
+
+    }
+
+    public void test_BBRNeedsCmosCpu() throws Exception {
+        makeNmosCpu();
+
+        /* BBR0 */
+        bus.write(0x0a,0xfe);
+        bus.loadProgram(0x0f, 0x0a, 0x05);  // 65C02 BBR0 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter());
+
+        /* BBR1 */
+        cpu.reset();
+        bus.write(0x0a,0xfd);
+        bus.loadProgram(0x1f, 0x0a, 0x05);  // 65C02 BBR1 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter());
+
+        /* BBR2 */
+        cpu.reset();
+        bus.write(0x0a,0xfb);
+        bus.loadProgram(0x2f, 0x0a, 0x05);  // 65C02 BBR2 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter());
+
+        /* BBR3 */
+        cpu.reset();
+        bus.write(0x0a,0xf7);
+        bus.loadProgram(0x3f, 0x0a, 0x05);  // 65C02 BBR3 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter());
+
+        /* BBR4 */
+        cpu.reset();
+        bus.write(0x0a,0xef);
+        bus.loadProgram(0x4f, 0x0a, 0x05);  // 65C02 BBR4 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter());
+
+        /* BBR5 */
+        cpu.reset();
+        bus.write(0x0a,0xdf);
+        bus.loadProgram(0x5f, 0x0a, 0x05);  // 65C02 BBR5 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter());
+
+        /* BBR6 */
+        cpu.reset();
+        bus.write(0x0a,0xbf);
+        bus.loadProgram(0x6f, 0x0a, 0x05);  // 65C02 BBR6 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter());
+
+        /* BBR7 */
+        cpu.reset();
+        bus.write(0x0a,0x7f);
+        bus.loadProgram(0x7f, 0x0a, 0x05);  // 65C02 BBR7 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter());
+
+    }
+
+    public void test_BBS() throws Exception {
+        makeCmosCpu();
+
+        /* BBS0 */
+        // Positive Offset
+        cpu.reset();
+        bus.write(0x0a,0x00);
+        bus.loadProgram(0x8f, 0x0a, 0x05);  // 65C02 BBS0 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter()); // Shouldn't have branched
+
+        cpu.reset();
+        bus.write(0x0a,0x01);
+        bus.loadProgram(0x8f, 0x0a, 0x05);  // 65C02 BBS0 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x208, cpu.getProgramCounter()); // Should have branched
+
+        // Negative Offset
+        cpu.reset();
+        bus.write(0x0a,0x01);
+        bus.loadProgram(0x8f, 0x0a, 0xfb);  // 65C02 BBS0 $00 $fb ; *=$0203-$05 ($01fe)
+        cpu.step();
+        assertEquals(0x1fe, cpu.getProgramCounter());
+
+        /* BBS1 */
+        // Positive Offset
+        cpu.reset();
+        bus.write(0x0a,0x00);
+        bus.loadProgram(0x9f, 0x00, 0x05);  // 65C02 BBS1 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter()); // Shouldn't have branched
+
+        cpu.reset();
+        bus.write(0x0a,0x02);
+        bus.loadProgram(0x9f, 0x0a, 0x05);  // 65C02 BBS1 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x208, cpu.getProgramCounter()); // Should have branched
+
+        // Negative Offset
+        cpu.reset();
+        bus.write(0x0a,0x02);
+        bus.loadProgram(0x9f, 0x0a, 0xfb);  // 65C02 BBS1 $00 $fb ; *=$0203-$05 ($01fe)
+        cpu.step();
+        assertEquals(0x1fe, cpu.getProgramCounter());
+
+        /* BBS2 */
+        // Positive Offset
+        cpu.reset();
+        bus.write(0x0a,0x00);
+        bus.loadProgram(0xaf, 0x0a, 0x05);  // 65C02 BBS2 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter()); // Shouldn't have branched
+
+        cpu.reset();
+        bus.write(0x0a,0x04);
+        bus.loadProgram(0xaf, 0x0a, 0x05);  // 65C02 BBS2 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x208, cpu.getProgramCounter()); // Should have branched
+
+        // Negative Offset
+        cpu.reset();
+        bus.write(0x0a,0x04);
+        bus.loadProgram(0xaf, 0x0a, 0xfb);  // 65C02 BBS2 $00 $fb ; *=$0203-$05 ($01fe)
+        cpu.step();
+        assertEquals(0x1fe, cpu.getProgramCounter());
+
+        /* BBS3 */
+        // Positive Offset
+        cpu.reset();
+        bus.write(0x0a,0x00);
+        bus.loadProgram(0xbf, 0x0a, 0x05);  // 65C02 BBS3 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter()); // Shouldn't have branched
+
+        cpu.reset();
+        bus.write(0x0a,0x08);
+        bus.loadProgram(0xbf, 0x0a, 0x05);  // 65C02 BBS3 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x208, cpu.getProgramCounter()); // Should have branched
+
+        // Negative Offset
+        cpu.reset();
+        bus.write(0x0a,0x08);
+        bus.loadProgram(0xbf, 0x0a, 0xfb);  // 65C02 BBS3 $00 $fb ; *=$0203-$05 ($01fe)
+        cpu.step();
+        assertEquals(0x1fe, cpu.getProgramCounter());
+
+        /* BBS4 */
+        // Positive Offset
+        cpu.reset();
+        bus.write(0x0a,0x00);
+        bus.loadProgram(0xcf, 0x0a, 0x05);  // 65C02 BBS4 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter()); // Shouldn't have branched
+
+        cpu.reset();
+        bus.write(0x0a,0x10);
+        bus.loadProgram(0xcf, 0x0a, 0x05);  // 65C02 BBS4 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x208, cpu.getProgramCounter()); // Should have branched
+
+        // Negative Offset
+        cpu.reset();
+        bus.write(0x0a,0x10);
+        bus.loadProgram(0xcf, 0x0a, 0xfb);  // 65C02 BBS4 $00 $fb ; *=$0203-$05 ($01fe)
+        cpu.step();
+        assertEquals(0x1fe, cpu.getProgramCounter());
+
+        /* BBS5 */
+        // Positive Offset
+        cpu.reset();
+        bus.write(0x0a,0x00);
+        bus.loadProgram(0xdf, 0x0a, 0x05);  // 65C02 BBS5 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter()); // Shouldn't have branched
+
+        cpu.reset();
+        bus.write(0x0a,0x20);
+        bus.loadProgram(0xdf, 0x0a, 0x05);  // 65C02 BBS5 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x208, cpu.getProgramCounter()); // Should have branched
+
+        // Negative Offset
+        cpu.reset();
+        bus.write(0x0a,0x20);
+        bus.loadProgram(0xdf, 0x0a, 0xfb);  // 65C02 BBS5 $00 $fb ; *=$0203-$05 ($01fe)
+        cpu.step();
+        assertEquals(0x1fe, cpu.getProgramCounter());
+
+        /* BBS6 */
+        // Positive Offset
+        cpu.reset();
+        bus.write(0x0a,0x00);
+        bus.loadProgram(0xef, 0x0a, 0x05);  // 65C02 BBS6 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter()); // Shouldn't have branched
+
+        cpu.reset();
+        bus.write(0x0a,0x40);
+        bus.loadProgram(0xef, 0x0a, 0x05);  // 65C02 BBS6 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x208, cpu.getProgramCounter()); // Should have branched
+
+        // Negative Offset
+        cpu.reset();
+        bus.write(0x0a,0x40);
+        bus.loadProgram(0xef, 0x0a, 0xfb);  // 65C02 BBS6 $00 $fb ; *=$0203-$05 ($01fe)
+        cpu.step();
+        assertEquals(0x1fe, cpu.getProgramCounter());
+
+        /* BBS7 */
+        // Positive Offset
+        cpu.reset();
+        bus.write(0x0a,0x00);
+        bus.loadProgram(0xff, 0x0a, 0x05);  // 65C02 BBS7 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter()); // Shouldn't have branched
+
+        cpu.reset();
+        bus.write(0x0a,0x80);
+        bus.loadProgram(0xff, 0x0a, 0x05);  // 65C02 BBS7 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x208, cpu.getProgramCounter()); // Should have branched
+
+        // Negative Offset
+        cpu.reset();
+        bus.write(0x0a,0x80);
+        bus.loadProgram(0xff, 0x0a, 0xfb);  // 65C02 BBS7 $00 $fb ; *=$0203-$05 ($01fe)
+        cpu.step();
+        assertEquals(0x1fe, cpu.getProgramCounter());
+
+    }
+
+    public void test_BBSNeedsCmosCpu() throws Exception {
+        makeNmosCpu();
+
+        /* BBS0 */
+        cpu.reset();
+        bus.write(0x0a,0x01);
+        bus.loadProgram(0x8f, 0x0a, 0x05);  // 65C02 BBS0 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter());
+
+        /* BBS1 */
+        cpu.reset();
+        bus.write(0x0a,0x02);
+        bus.loadProgram(0x9f, 0x0a, 0x05);  // 65C02 BBS1 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter());
+
+        /* BBS2 */
+        cpu.reset();
+        bus.write(0x0a,0x04);
+        bus.loadProgram(0xaf, 0x0a, 0x05);  // 65C02 BBS2 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter());
+
+        /* BBS3 */
+        cpu.reset();
+        bus.write(0x0a,0x08);
+        bus.loadProgram(0xbf, 0x0a, 0x05);  // 65C02 BBS3 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter());
+
+        /* BBS4 */
+        cpu.reset();
+        bus.write(0x0a,0x10);
+        bus.loadProgram(0xcf, 0x0a, 0x05);  // 65C02 BBS4 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter());
+
+        /* BBS5 */
+        cpu.reset();
+        bus.write(0x0a,0x20);
+        bus.loadProgram(0xdf, 0x0a, 0x05);  // 65C02 BBS5 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter());
+
+        /* BBS6 */
+        cpu.reset();
+        bus.write(0x0a,0x40);
+        bus.loadProgram(0xef, 0x0a, 0x05);  // 65C02 BBS6 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter());
+
+        /* BBS7 */
+        cpu.reset();
+        bus.write(0x0a,0x80);
+        bus.loadProgram(0xff, 0x0a, 0x05);  // 65C02 BBS7 $00 $05 ; *=$0202+$05 ($0208)
+
+        cpu.step();
+        assertEquals(0x203, cpu.getProgramCounter());
+
+    }
+
+}
Author	SHA1	Message	Date
Seth Morabito	105a09067f	Fix README for 1.3.1	2019-10-12 14:58:16 -07:00
Seth Morabito	08efd81be3	Merge branch 'master' into 1.3.branch	2019-10-12 14:55:43 -07:00
Seth Morabito	0aeb97bb56	Add new options -cpu and -rom	2019-10-12 14:54:05 -07:00
Seth Morabito	d466a21b3e	Fix README screenshots (again)	2018-07-09 14:00:32 -07:00
Seth Morabito	31d1f7c5e1	Update screenshots	2018-03-01 19:21:56 -08:00
Seth Morabito	247f2ba2fc	Update screenshots	2018-03-01 19:21:21 -08:00
Seth Morabito	922810b34b	Update POM for 1.3.0	2018-02-25 11:46:02 -08:00
Seth Morabito	9d6791330d	Update README	2018-02-25 11:45:16 -08:00
Seth Morabito	73c474d606	POM cleanup	2018-02-04 11:49:26 -08:00
Chris Cureau	71905fdb19	Merge pull request #23 from ccureau/master Integrate jterminal	2017-09-12 18:23:55 -05:00
ccureau	cb918c9906	Remove unnecessary package-info files	2017-08-30 10:40:45 -05:00
ccureau	be72c2ff09	implement jterminal in source	2017-08-30 10:34:50 -05:00
ccureau	18ce120984	Add jterminal to source	2017-08-30 09:23:59 -05:00
Seth Morabito	8ffb130300	Merge pull request #21 from LIV2/master Fix PHY/PLY Addressing mode	2017-08-23 10:47:12 -07:00
Matt Harlum	441f7349a0	Fix PHY/PLY Addressing mode	2017-06-19 11:49:46 +10:00
Seth Morabito	4f27e78940	Merge pull request #20 from LIV2/master Add cycle counts for illegal NMOS opcodes	2017-06-06 19:47:24 -07:00
Matt Harlum	11f61f50a9	Add cycle counts for illegal NMOS opcodes	2017-06-07 12:20:21 +10:00
Seth Morabito	59f8ff1bc4	Merge pull request #19 from LIV2/master Adds support for all 65C02 Opcodes	2017-06-06 07:10:02 -07:00
Matt Harlum	a9c6d5964f	* Add Support for All 65C02 Opcodes and all Rockwell/WDC opcodes except WAI/STP * Add 65C02 Opcode tests * All tests pass, Klaus' 6502_functional_tests pass & Klaus' 65C02_extended_opcodes_test also all pass	2017-06-06 19:59:01 +10:00
Matt Harlum	faf5d22660	* Add ACIA Interrupt tests. * Fix ACIA6850 Interrupt behavior, Interrupt should be cleared on status register read. * Remove unneeded cpuAccess if statement from Acia6850 write that was preventing build completion * Fix ACIA6850 Tests so they run.	2017-06-06 12:55:35 +10:00
Seth Morabito	3c3aee30a7	Merge pull request #18 from izuannazrin/master Interrupt bit support for ACIA	2017-06-04 18:53:44 -07:00
Izuan Nazrin	92f8fe3dd9	Fixed 6850 behaviour + Fixed interrupt bit reset behaviour	2017-05-30 01:33:12 +08:00
Izuan Nazrin	356822df71	Fixed typo + Fixed typo in Acia.java statusReg declaration	2017-05-30 01:14:50 +08:00
Izuan Nazrin	f2ced29979	Added interrupt support for ACIA + Added interrupt support for ACIA + Auto-formatting (in case anyone cares)	2017-05-29 02:03:18 +08:00
Seth Morabito	2e33756d49	Merge pull request #17 from LIV2/master Memory window should not reset device registers	2017-05-26 09:38:28 -07:00
Matt Harlum	079d3dbeae	Fix README links	2017-05-26 17:01:48 +10:00
Matt Harlum	96819f1bf7	Issue #16 : Memory window should not reset device registers	2017-05-26 17:01:41 +10:00
Seth Morabito	9cdd718e8d	Fix Screenshots part two	2017-03-20 07:49:32 -07:00
Seth Morabito	5554acd29c	Fix screenshots	2017-03-20 07:39:49 -07:00
Seth Morabito	5a2e057e69	Minor whitespace cleanup	2016-06-11 11:46:31 -07:00
Seth Morabito	da88aadda2	Merge pull request #15 from LIV2/master Correct BRK/IRQ behavior	2016-03-20 11:43:42 -07:00
Matt Harlum	657b69da6c	Cleanup my comments	2016-03-20 17:05:48 +11:00
Chris Cureau	f251e54174	Merge pull request #13 from sethm/cc65_update_patches update Makefiles and configuration for latest cc65	2016-03-14 20:01:12 -05:00
Chris Cureau	fcc57d9be4	update Makefiles and configuration for latest cc65	2016-01-12 08:14:38 -06:00
Seth Morabito	88eba2cdcb	Merge branch '1.2.branch'	2016-01-08 20:53:54 -08:00
Seth Morabito	0e49b197b3	Update README for 1.2.1	2016-01-08 20:52:02 -08:00
Seth Morabito	b59fa63b63	Merge branch '1.2.branch'	2016-01-08 20:41:25 -08:00
Seth Morabito	eff98118d5	Fix a few straggling Java 8-isms.	2016-01-08 20:40:23 -08:00
Seth Morabito	c599df1cfb	Set version to 1.3.0-SNAPSHOT	2016-01-08 19:14:00 -08:00
Seth Morabito	66c52c8826	Revert Java 1.8 changes. Buildable with Java 1.7 There are still active users on Java 1.7, so building with Java 8 was a no-no. This change reverts the recent migration to Java 8, allowing JDK 1.7 to compile the code. This means, at least for the time being, no more Lambda expressions (Boooooooooooooooo!!)	2016-01-08 19:11:42 -08:00
Seth Morabito	f3a5dd93ad	Release 1.2.0	2016-01-03 11:01:20 -08:00
Seth Morabito	4044458baa	Fix typo	2016-01-03 10:59:11 -08:00
Seth Morabito	9ab94b3050	Prep for 1.2	2016-01-03 10:56:16 -08:00
Seth Morabito	9a504adc58	Added roadmap to README	2016-01-03 10:49:41 -08:00
Seth Morabito	57cbff42e7	Merge branch '1.1.branch'	2016-01-02 19:06:23 -08:00
Seth Morabito	634ea933f1	Add disassembled instructions to breakpoints	2016-01-02 19:05:38 -08:00
Seth Morabito	0ca30291cb	Merge branch '1.1.branch'	2016-01-02 09:51:20 -08:00
Seth Morabito	95f85b71b1	Enter key can add breakpoints	2016-01-02 09:50:38 -08:00
Seth Morabito	6b5976be8f	Update for 1.1.1 release	2016-01-02 09:46:12 -08:00
Seth Morabito	3530e9e99a	Enter key can add breakpoints	2016-01-02 09:40:34 -08:00
Seth Morabito	7a9f9bfd55	Update images for 1.1.0	2016-01-01 09:49:39 -08:00
Seth Morabito	1e04a52d1b	Prep for 1.2	2016-01-01 09:44:43 -08:00
Seth Morabito	7daeb9e978	Update README for 1.1.0	2015-12-31 16:38:27 -08:00
Seth Morabito	da2750f4ee	Release 1.1.0	2015-12-31 16:19:06 -08:00
Seth Morabito	df88c54f90	Support for breakpoints - Adds a new window that allows adding and deleting breakpoints. Will halt the simulator when a breakpoint is reached.	2015-12-31 16:09:50 -08:00
Seth Morabito	69e1985ec1	Update README	2015-12-30 11:03:23 -08:00
Seth Morabito	6267d1d777	Allow runtime selection of CPU speed	2015-12-30 10:56:03 -08:00
Seth Morabito	84e5c5ad56	Refactor delay loop	2015-12-30 10:08:44 -08:00
Seth Morabito	6e8fd40014	Refactor for Java 1.8 - Clean up and refactor code - Add 1.8 features - Clean up IntelliJ inspector warnings	2015-12-29 17:55:41 -08:00
Seth Morabito	a4a110dcef	Bugfixes, change logger, update copyright - IR field in status panel now correctly displays the next instruction to be executed, instead of the instruction that was just executed. - Switched from built-in Java util logger to Logback - Updated all copyright strings to 2016	2015-12-29 14:40:42 -08:00
Matt Harlum	8335cf5421	Correct BRK behaviour IRQ/NMI clear the BRK flag BRK is Non-Maskable	2015-06-01 08:58:17 +10:00
Seth Morabito	ae5c5d48b2	Merge pull request #12 from maikmerten/master mask all bits beyond bits 0 to 7 on bus reads to ensure no surplus bits ...	2014-08-23 16:59:56 -07:00
Maik Merten	72ba068beb	mask all bits beyond bits 0 to 7 on bus reads to ensure no surplus bits cause unpredictable system behavior.	2014-08-23 16:50:34 +02:00
Seth Morabito	142cb470a0	Converging on a useful CRTC ROM	2014-08-18 19:52:09 -07:00
Seth Morabito	cad3673bd2	Formatting; uppercase	2014-08-16 16:54:36 -07:00
Seth Morabito	4796b65390	New ROMs. Better backspace handling.	2014-08-16 14:28:54 -07:00
Seth Morabito	e0d6017d95	Unifying and cleaning up copyrights	2014-08-16 13:50:47 -07:00
Seth Morabito	d6ea21bae4	Mostly working CRTC	2014-08-15 15:21:02 -07:00
Seth Morabito	af12039686	Merge pull request #10 from maikmerten/master Multicomp: SD card controller emulation	2014-08-15 13:51:26 -07:00
Seth Morabito	ed1d5f999b	Preparing for real implementation	2014-08-15 12:48:54 -07:00
Maik Merten	c595ff5370	README update	2014-08-15 20:15:04 +02:00
Maik Merten	e9f662cc17	Merge remote-tracking branch 'upstream/master' Conflicts: src/main/java/com/loomcom/symon/machines/MulticompMachine.java	2014-08-15 20:11:33 +02:00
Seth Morabito	70ab2a6fc2	More CRTC tinkering	2014-08-14 21:03:52 -07:00
Seth Morabito	f35fbce38b	Add CRTC EhBASIC, switch char rom.	2014-08-14 11:50:51 -07:00
Seth Morabito	eeb246ebc2	CRTC refactoring	2014-08-14 10:53:48 -07:00
Seth Morabito	e157217f50	Fix missing repaint on Video Window	2014-08-13 15:46:20 -07:00
Maik Merten	cc12e8f70a	proper status value when SD controller is in write mode	2014-08-13 19:56:40 +02:00
Maik Merten	a9a1c1aa52	get writing to a certain position in a file somewhat more correct	2014-08-13 19:38:54 +02:00
Seth Morabito	742e3a1027	Split PIA into PIA/VIA6522	2014-08-12 15:06:08 -07:00
Seth Morabito	45f596e0d4	Rename VIA to PIA Preparing to create a PIA interface and one or more parallel IO device implementations.	2014-08-12 14:19:55 -07:00
Seth Morabito	4402a28e2b	Update README	2014-08-12 14:05:19 -07:00
Maik Merten	693d1959ac	finer grained synchronization in TraceLog. Profiling indicates that this speeds up adding log entries quite considerably.	2014-08-12 21:58:52 +02:00
Maik Merten	792366fddb	some cleanup in the SD card controller	2014-08-12 21:34:00 +02:00
Maik Merten	b2670aedf1	email address update	2014-08-12 19:25:37 +02:00
Maik Merten	5d488bbcd2	Merge remote-tracking branch 'upstream/master'	2014-08-12 11:48:47 +02:00
Seth Morabito	e2a1144c7c	Update copyright, prep for 1.1.0	2014-08-11 14:16:41 -07:00
Seth Morabito	ac5907691f	Release version 1.0.0	2014-08-11 13:49:48 -07:00
Seth Morabito	fce0dad2a9	Removed unused constant	2014-08-11 13:40:21 -07:00
Seth Morabito	0c40cd325c	Alert dialogs for ROM/Program loading	2014-08-11 13:36:31 -07:00
Seth Morabito	22a9207dca	Fix for GitHub Issue #9	2014-08-11 13:36:08 -07:00
Maik Merten	010c42753f	Merge remote-tracking branch 'upstream/master'	2014-08-11 09:34:44 +02:00
Seth Morabito	7c2a007928	Add Hard/Soft reset buttons	2014-08-10 20:42:39 -07:00
Seth Morabito	194a13d1ac	Make register fields editable	2014-08-10 20:33:54 -07:00
Seth Morabito	66646116cb	README update	2014-08-10 17:34:13 -07:00
Seth Morabito	59c6d8e23b	Added Klaus Dormann's tests	2014-08-10 16:52:20 -07:00
Seth Morabito	36615fc70b	Move images to resources	2014-08-10 15:19:59 -07:00
Seth Morabito	1a1d503abe	Make PC editable	2014-08-10 14:24:43 -07:00
Seth Morabito	eac387e472	Make StatusPanel aware of the Machine	2014-08-10 14:08:15 -07:00
Seth Morabito	bb82db6672	Version 1.0.0-SNAPSHOT	2014-08-10 14:00:18 -07:00
Seth Morabito	f675a6e462	Merge branch 'master' of github.com:sethm/symon	2014-08-10 13:54:50 -07:00
Seth Morabito	ccae8905b3	Implement SimpleMachine	2014-08-10 13:53:04 -07:00
Maik Merten	7a215736fe	rework SD controller emulation to work with Input- and OutputStreams (no longer load the image into a byte array)	2014-08-09 17:55:18 +02:00
Maik Merten	c61a63d5bb	more accurate emulation of the SD controller	2014-08-09 16:47:49 +02:00
Maik Merten	7cb4e1c945	NPE fix and reset position on every command	2014-08-09 15:13:59 +02:00
Maik Merten	3a40d35fdf	use SD interface in MulticompMachine and lift the speed limit on the ACIA device to better match the experience on the real machine	2014-08-09 14:58:29 +02:00
Maik Merten	d658cd0ae5	completely untested and incomplete implementation of the SD card interface of the MULTICOMP	2014-08-09 14:57:18 +02:00
Seth Morabito	6b9295e72d	Merge pull request #7 from maikmerten/master invoke setBus() on devices added to the bus	2014-07-28 10:13:09 -07:00
Maik Merten	004087a742	invoke setBus() on devices added to the bus	2014-07-28 18:19:52 +02:00
Seth Morabito	7edbb12f68	Merge branch 'reset-wip'	2014-07-27 13:42:18 -07:00
Seth Morabito	4bfc196b49	Clear memory on Control+Reset	2014-07-27 13:41:44 -07:00
Seth Morabito	b1e1e75555	Reset WIP	2014-07-27 11:33:08 -07:00
Seth Morabito	da3015defd	Merge pull request #6 from maikmerten/master minor typo fixes in README.md	2014-07-26 14:15:06 -07:00
Maik Merten	87b5b77dbf	minor typo fixes in README.m	2014-07-26 23:07:06 +02:00
Seth Morabito	2dc0078deb	Release 0.9.9.0	2014-07-26 13:23:42 -07:00
Seth Morabito	ac21b2c126	Updates for 0.9.9	2014-07-26 13:18:07 -07:00
Seth Morabito	4bb6d55fa2	Merge pull request #5 from maikmerten/master Infrastructure for several machine types, Bus reworkings, 6850 ACIA and more	2014-07-26 12:46:45 -07:00
Maik Merten	f90516e53c	fix a possible NPE	2014-07-26 18:55:51 +02:00
Maik Merten	fdaeb661d3	add menu entry to allow to switch the emulated machine type	2014-07-26 18:52:57 +02:00
Maik Merten	827e9991d5	move main method into Main class in anticipation of changes that allow restarting the complete UI from within the Simulator menu system	2014-07-26 18:07:29 +02:00
Maik Merten	dc7dfc4b4d	code simplification	2014-07-25 21:44:43 +02:00
Maik Merten	2217f3831d	slight JavaDoc fix regarding what Exception can be thrown	2014-07-25 21:27:40 +02:00
Maik Merten	52f4e9a00f	enforce that the address range of devices falls within the address range of the bus. Turned out that the CPU tests instantiate memory with the last parameter as memory size, not end address (fixed now). Also make sure that the address lookup array takes the offset caused by non-zero starting addresses into account.	2014-07-25 21:24:16 +02:00
Maik Merten	d7f8045b61	rework bus. Don't throw an Exception any more with overlapping device addresses - this is normal for some machines. Introduce the concept of priorities to ensure that device overlap in the correct order.	2014-07-25 19:32:00 +02:00
Maik Merten	222772648d	simple dialog for choosing machine model when no command-line option was given	2014-07-22 17:50:06 +02:00
Maik Merten	bd2337ae65	allow for selecting the emulated machien type with the "-machine" parameter. The default is the Symon machine model, the Multicomp machine can be selected with "-machine multicomp".	2014-07-21 17:39:20 +02:00
Maik Merten	a49c0d40d8	revert back to busy waiting for CPU speed emulation to have a less bursty CPU behavior	2014-07-20 21:55:01 +02:00
Maik Merten	44bfbc17ab	replace busy waiting to emulate "proper" CPU speed with some time book keeping and thread sleeping	2014-07-19 20:19:26 +02:00
Maik Merten	b266a02372	have full 56K of RAM for the Multicomp machine	2014-07-19 17:51:51 +02:00
Maik Merten	72074b9715	Silence a compiler warning regarding generics	2014-07-19 17:40:19 +02:00
Maik Merten	252ebe0569	implement overrun status flag for the 6551 ACIA	2014-07-19 17:30:23 +02:00
Maik Merten	4a37dd7463	move overrun detection and reset into the abstract superclass for ACIAs	2014-07-19 17:10:57 +02:00
Maik Merten	cf36f731da	make use of the MulticompMachine in the simulator. This should be an option, not hardcoded.	2014-07-17 21:59:03 +02:00
Maik Merten	e01f68a19a	make use of overlapping memory regions in MulticompMachine	2014-07-17 21:45:37 +02:00
Maik Merten	44151f3a9c	have the Bus support devices with overlapping memory regions	2014-07-17 21:43:46 +02:00
Maik Merten	f5a25b7303	initial definition of the MULTICOMP machine. Will not yet run, as the bus will currently not allow overlapping memory ranges for devices.	2014-07-17 20:41:26 +02:00
Maik Merten	14e8ea596c	define an interface for supported machines and have the SymonMachine as first implementation. Remove machine-specific definitions out of the Simulator class.	2014-07-17 19:42:51 +02:00
Maik Merten	8f52e1da1e	implement overrun flag for 6850 ACIA	2014-07-16 22:26:06 +02:00
Maik Merten	0d0fddc365	tests for the 6850 ACIA and fixes in ACIA behavior	2014-07-16 21:51:34 +02:00
Maik Merten	31fdd87b41	turn Acia into an abstract class so that the 6551 and 6850 ACIAs can reuse code and an unified interface.	2014-07-15 21:35:19 +02:00
Maik Merten	9726907317	initial (and untested) implementation of a Motorola 6850 ACIA	2014-07-15 18:45:13 +02:00
Seth Morabito	40c5397ed8	Faster refresh of memory window	2014-07-06 12:17:39 -07:00