Fleshing out some of the interface for the CPU, Simulator, and Devices.

src/main/java/com/loomcom/j6502/AddressDecoder.java

@@ -0,0 +1,72 @@
+package com.loomcom.j6502;
+
+import java.util.Map;
+
+public class AddressDecoder {
+
+    /**
+     * Map of memory ranges to IO devices.
+     */
+    private Map<MemoryRange, Device> m_ioMap;
+    
+    public AddressDecoder() {}
+
+    public void addDevice(Device d) 
+	throws MemoryConflictException {
+	// Make sure there's no memory overlap.
+	// Add the device to the map.
+    }
+
+    /**
+     * Returns true if the memory map is full, i.e., there are no
+     * gaps between any IO devices.  All memory locations map to some
+     * device.
+     */
+    public boolean isComplete() {
+	return true;
+    }
+
+    /** 
+     * Returns true if the memory map is 'sparse', i.e., there
+     * are gaps between IO devices.
+     */
+    public boolean isSparse() {
+	return !isComplete();
+    }
+
+}
+
+class MemoryRange {
+    public int m_startAddress;
+    public int m_endAddress;
+
+    /**
+     * @returns true if the address is included within this range,
+     *          false otherwise.
+     */
+    public boolean includes(int address) {
+	return (address <= m_endAddress &&
+		address >= m_startAddress);
+    }
+
+    public void setStartAddress(int startAddress) {
+	m_startAddress = startAddress;
+    }
+
+    public void setEndAddress(int endAddress) {
+	m_endAddress = endAddress;
+    }
+
+    public int getStartAddress() {
+	return m_startAddress;
+    }
+
+    public int getEndAddress() {
+	return m_endAddress;
+    }
+}
+
+/**
+ * Excption that will be thrown if devices conflict in the IO map.
+ */
+class MemoryConflictException extends Exception {}

src/main/java/com/loomcom/j6502/CommandParser.java

@@ -6,8 +6,9 @@ public class CommandParser {
     
     private BufferedReader m_in;
     private BufferedWriter m_out;
+    private Simulator m_simulator;
     
-    public CommandParser(InputStream in, OutputStream out) {
+    public CommandParser(InputStream in, OutputStream out, Simulator s) {
 	m_in  = new BufferedReader(new InputStreamReader(in));
 	m_out = new BufferedWriter(new OutputStreamWriter(out));
     }
@@ -21,7 +22,7 @@ public class CommandParser {
 		dispatch(command);
 		prompt();
 	    }
-	    writeLine("Goodbye!");
+	    writeLine("\n\nGoodbye!");
 	} catch (IOException ex) {
 	    System.err.println("Error: " + ex.toString());
 	    System.exit(1);

src/main/java/com/loomcom/j6502/Control.java

@@ -1,17 +0,0 @@
-package com.loomcom.j6502;
-
-import java.io.IOException;
-
-/**
- * Main control class for the J6502 Simulator.
- */
-public class Control {
-
-    public static void main(String[] args) {
-
-	CommandParser parser = new CommandParser(System.in, System.out);
-	parser.run();
-
-    }
-
-}

src/main/java/com/loomcom/j6502/Cpu.java

@@ -0,0 +1,52 @@
+package com.loomcom.j6502;
+
+/**
+ * Main 6502 CPU Simulation.
+ */
+public class Cpu {
+
+    /**
+     * The Address Decoder responsible for routing memory
+     * read/write requests to the correct IO devices.  Any
+     * simulated device can be 
+     */
+    AddressDecoder m_adc;
+
+    /**
+     * The Program Counter.
+     */
+    int m_pc;
+
+    /**
+     * The system stack pointer.
+     */
+    int m_sp;
+
+    /**
+     * The internal 
+     */
+
+    public Cpu() {
+	reset();
+    }
+
+    /**
+     * Reset the CPU to known initial values.
+     */
+    public void reset() {
+    }
+
+    /** 
+     * Trigger a maskable interrupt.
+     */
+    public void interrupt() {
+    }
+
+    /**
+     * Trigger a nonmaskable interrupt.
+     */
+    public void nmiInterrupt() {
+    }
+    
+}
+

src/main/java/com/loomcom/j6502/Device.java

@@ -0,0 +1,28 @@
+package com.loomcom.j6502;
+
+/**
+ * A memory-mapped IO Device.
+ */
+
+public abstract class Device {
+
+    /** The memory range for this device. */
+    private MemoryRange m_memoryRange;
+
+    /** Referece to the CPU, for interrupts. */
+    private Cpu m_cpu;
+    
+    public Device(MemoryRange range, Cpu cpu) {
+	m_memoryRange = range;
+	m_cpu = cpu;
+    }
+
+    public void generateInterrupt() {
+	m_cpu.interrupt();
+    }
+
+    public void generateNonMaskableInterrupt() {
+	m_cpu.nmiInterrupt();
+    }
+
+}

src/main/java/com/loomcom/j6502/Simulator.java

@@ -0,0 +1,30 @@
+package com.loomcom.j6502;
+
+import java.io.IOException;
+
+/**
+ * Main control class for the J6502 Simulator.
+ */
+public class Simulator {
+    
+    CommandParser m_parser;
+    Cpu m_cpu;
+    
+    public Simulator() {
+	m_cpu = new Cpu();
+	m_parser = new CommandParser(System.in, System.out, this);
+    }
+
+    public void run() {
+	m_parser.run();
+    }
+    
+    public static void main(String[] args) {
+	new Simulator().run();
+    }
+
+    public void step() {
+	
+    }
+    
+}