Changed the CPU and Device interface a bit.

src/main/java/com/loomcom/lm6502/Bus.java

@@ -4,15 +4,17 @@ import java.util.*;
 import com.loomcom.lm6502.devices.*;
 import com.loomcom.lm6502.exceptions.*;
 
+/**
+ * The Bus ties the whole thing together, man.
+ */
 public class Bus {
 
-	/* By default, our bus starts at 0, and goes up to 64K */
+	// By default, our bus starts at 0, and goes up to 64K
 	private int startAddress = 0x0000;
 	private int endAddress   = 0xffff;
-
-	/**
-	 * Ordered list of IO devices.
-	 */
+	// The CPU
+	private Cpu cpu;
+	// Ordered list of IO devices.
 	private SortedSet<Device> devices;
 
 	public Bus(int size) {
@@ -45,9 +47,14 @@ public class Bus {
 		}
 
 		// Add the device
+		device.setBus(this);
 		devices.add(device);
 	}
 
+	public void addCpu(Cpu cpu) {
+		this.cpu = cpu;
+	}
+
 	/**
 	 * Returns true if the memory map is full, i.e., there are no
 	 * gaps between any IO devices.	 All memory locations map to some

src/main/java/com/loomcom/lm6502/Cpu.java

@@ -5,13 +5,38 @@ package com.loomcom.lm6502;
  */
 public class Cpu {
 
-	private int pc;
-	private int sp;
-	private Simulator sim;
+	/* The Bus */
+	private Bus bus;
 
-	public Cpu(Simulator sim) {
+	/* User Registers */
+	private int a;    // Accumulator
+	private int x;    // X index register
+	private int y;    // Y index register
+
+	/* Internal Registers */
+	private int pc;   // Program Counter register
+	private int sp;   // Stack Pointer register
+	private int ir;   // Instruction register
+
+	/**
+	 * Construct a new CPU.
+	 */
+	public Cpu() {
 		reset();
-		this.sim = sim;
+	}
+
+	/**
+	 * Set the bus reference for this CPU.
+	 */
+	public void setBus(Bus bus) {
+		this.bus = bus;
+	}
+
+	/**
+	 * Return the Bus that this CPU is associated with.
+	 */
+	public Bus getBus() {
+		return bus;
 	}
 
 	/**
@@ -19,43 +44,8 @@ public class Cpu {
 	 */
 	public void reset() {
 		sp = 0x01ff;
-		/* locations fffc and fffd hold the reset vector address */
 		pc = 0xfffc;
-	}
-
-	/**
-	 * Trigger a maskable interrupt.
-	 */
-	public void interrupt() {
-	}
-
-	/**
-	 * Trigger a nonmaskable interrupt.
-	 */
-	public void nmiInterrupt() {
-	}
-
-	/**
-	 * @return An address specified by the two bytes immediately following the
-	 *         Program Counter.
-	 */
-	private int readAddress() {
-		return readAddress(pc);
-	}
-
-	/**
-	 * Read the two bytes located at <tt>addr</tt> and <tt>addr + 1</tt>,
-	 * and return the address held there.
-	 *
-	 * @param address
-	 * @return The address specified in the two bytes at location <tt>addr</tt>
-	 */
-	private int readAddress(int address) {
-		return (sim.read(address)<<8 & sim.read(address+1));
-	}
-
-	public Simulator getSimulator() {
-		return sim;
+		ir = 0;
 	}
 
 }

src/main/java/com/loomcom/lm6502/Profiler.java

@@ -18,14 +18,14 @@ public class Profiler {
 			Bus b = new Bus(0, 65535);
 
 			// Create eight devices, each 8KB, to fill the bus.
-			b.addDevice(new Memory(0x0000, 0x2000, null)); // 8KB @ $0000-$1fff
-			b.addDevice(new Memory(0x2000, 0x2000, null)); // 8KB @ $2000-$3fff
-			b.addDevice(new Memory(0x4000, 0x2000, null)); // 8KB @ $4000-$5fff
-			b.addDevice(new Memory(0x6000, 0x2000, null)); // 8KB @ $6000-$7fff
-			b.addDevice(new Memory(0x8000, 0x2000, null)); // 8KB @ $8000-$9fff
-			b.addDevice(new Memory(0xa000, 0x2000, null)); // 8KB @ $a000-$bfff
-			b.addDevice(new Memory(0xc000, 0x2000, null)); // 8KB @ $c000-$dfff
-			b.addDevice(new Memory(0xe000, 0x2000, null)); // 8KB @ $e000-$ffff
+			b.addDevice(new Memory(0x0000, 0x2000)); // 8KB @ $0000-$1fff
+			b.addDevice(new Memory(0x2000, 0x2000)); // 8KB @ $2000-$3fff
+			b.addDevice(new Memory(0x4000, 0x2000)); // 8KB @ $4000-$5fff
+			b.addDevice(new Memory(0x6000, 0x2000)); // 8KB @ $6000-$7fff
+			b.addDevice(new Memory(0x8000, 0x2000)); // 8KB @ $8000-$9fff
+			b.addDevice(new Memory(0xa000, 0x2000)); // 8KB @ $a000-$bfff
+			b.addDevice(new Memory(0xc000, 0x2000)); // 8KB @ $c000-$dfff
+			b.addDevice(new Memory(0xe000, 0x2000)); // 8KB @ $e000-$ffff
 
 			// Read memory
 			long sum     = 0;
@@ -42,7 +42,8 @@ public class Profiler {
 				for (int j = 0; j < 0xffff; j++) {
 					buf = b.read(j);
 					if (buf != 0xff) {
-						System.out.println("WARNING!  MEMORY SHOULD HAVE BEEN $FF, WAS: " + buf);
+						System.out.println("WARNING!  MEMORY SHOULD HAVE " +
+															 "BEEN $FF, WAS: " + buf);
 						System.exit(0);
 					}
 				}
@@ -50,15 +51,13 @@ public class Profiler {
 				long endTime = System.nanoTime();
 				long diff    = endTime - startTime;
 
-				// System.out.println("Read of 64KB took: " + diff + " ns (" + (diff / 1000) + " us)");
-
 				sum += diff;
 				average = sum / (i + 1);
 			}
-
-			System.out.println("Average time to read 64KB: " + average + " ns (" + (average / 1000) + " us)");
-			System.out.println("Average time to read one byte: " + sum / (64 * 1024 * iters) + " ns");
-
+			System.out.println("Average time to read 64KB: " + average +
+												 " ns (" + (average / 1000) + " us)");
+			System.out.println("Average time to read one byte: " +
+												 sum / (64 * 1024 * iters) + " ns");
 		} catch (MemoryRangeException ex) {
 			System.out.println("Memory Access Exception! " + ex.getMessage());
 		}

src/main/java/com/loomcom/lm6502/Simulator.java

@@ -10,21 +10,21 @@ public class Simulator {
 	/**
 	 * Command-line parser used by this simulator.
 	 */
-	CommandParser parser;
+	private CommandParser parser;
 
 	/**
 	 * The CPU itself.
 	 */
-	Cpu cpu;
+	private Cpu cpu;
 
 	/**
 	 * The Bus responsible for routing memory read/write requests to the
 	 * correct IO devices.
 	 */
-	Bus bus;
+	private Bus bus;
 
 	public Simulator() {
-		cpu = new Cpu(this);
+		cpu = new Cpu();
 		parser = new CommandParser(System.in, System.out, this);
 	}
 

src/main/java/com/loomcom/lm6502/devices/Device.java

@@ -12,16 +12,20 @@ public abstract class Device implements Comparable<Device> {
 	/** The memory range for this device. */
 	private MemoryRange memoryRange;
 
+	/** The name of the device. */
 	private String name;
 
-	/** Reference to the CPU, for interrupts. */
-	private Cpu cpu;
+	/** Reference to the bus where this Device is attached. */
+	private Bus bus;
 
-	public Device(int address, int size, String name, Cpu cpu)
+	public Device(int address, int size, String name)
 		    throws MemoryRangeException {
 		this.memoryRange = new MemoryRange(address, address + size - 1);
 		this.name = name;
-		this.cpu = cpu;
+	}
+
+	public Device(int address, int size) throws MemoryRangeException {
+		this(address, size, null);
 	}
 
 	/* Methods required to be implemented by inheriting classes. */
@@ -29,6 +33,10 @@ public abstract class Device implements Comparable<Device> {
 	public abstract int read(int address);
 	public abstract String toString();
 
+	public void setBus(Bus bus) {
+		this.bus = bus;
+	}
+
 	public MemoryRange getMemoryRange() {
 		return memoryRange;
 	}

src/main/java/com/loomcom/lm6502/devices/Memory.java

@@ -8,29 +8,24 @@ import com.loomcom.lm6502.exceptions.*;
 public class Memory extends Device {
 
 	private boolean readOnly;
-
 	private int[] mem;
 
-	public Memory(int address, int size, Cpu cpu, boolean readOnly)
+	public Memory(int address, int size, boolean readOnly)
 		    throws MemoryRangeException {
-		super(address, size, "RW Memory", cpu);
-
+		super(address, size, "RW Memory");
 		this.readOnly = readOnly;
 		this.mem = new int[size];
-
-		// Init the mem to all 0xff
+		// Initialize all locations to 0xff
 		Arrays.fill(this.mem, 0xff);
 	}
 
-	public Memory(int address, int size, Cpu cpu)
+	public Memory(int address, int size)
 		    throws MemoryRangeException {
-		this(address, size, cpu, false);
+		this(address, size, false);
 	}
 
 	public void write(int address, int data) {
-		System.out.println(String.format("[write] Before write: $%04x=$%04x", address, this.mem[address]));
 		this.mem[address] = data;
-		System.out.println(String.format("[write] After write:  $%04x=$%04x", address, this.mem[address]));
 	}
 
 	public int read(int address) {