Tests for AddressDecoder. Fixed a bug in isComplete().

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

@@ -4,30 +4,45 @@ import java.util.*;
 
 public class AddressDecoder {
 
-	public static final int MEMORY_BOTTOM = 0x0000;
-	public static final int MEMORY_TOP = 0xFFFF;
+	private int bottom = 0x0000;
+	private int top    = 0xffff;
 
 	/**
-	 * Ordered map of memory ranges to IO devices.
+	 * Ordered list of IO devices.
 	 */
-	private SortedMap<MemoryRange, Device> ioMap;
+	private List<Device> devices;
 
-	public AddressDecoder() {
-		ioMap = new TreeMap();
+	public AddressDecoder(int size) {
+		this(0, size - 1);
 	}
 
-	public void addDevice(Device d)
+	public AddressDecoder(int bottom, int top) {
+		this.devices = new ArrayList(8);
+		this.bottom = bottom;
+		this.top = top;
+	}
+
+	public int bottom() {
+		return bottom;
+	}
+
+	public int top() {
+		return top;
+	}
+
+	public void addDevice(Device device)
 		throws MemoryRangeException {
 		// Make sure there's no memory overlap.
-		for (MemoryRange memRange : ioMap.keySet()) {
+		MemoryRange memRange = device.getMemoryRange();
+		for (Device d : devices) {
 			if (d.getMemoryRange().overlaps(memRange)) {
 				throw new MemoryRangeException("The device being added overlaps " +
 																			 "with an existing device.");
 			}
 		}
 
-		// Add the device to the map.
-		ioMap.put(d.getMemoryRange(), d);
+		// Add the device
+		devices.add(device);
 	}
 
 	/**
@@ -37,27 +52,32 @@ public class AddressDecoder {
 	 */
 	public boolean isComplete() {
 		// Emtpy maps cannot be complete.
-		if (ioMap.isEmpty()) { return false; }
+		if (devices.isEmpty()) { return false; }
 
 		// Loop over devices and ensure they are contiguous.
 		MemoryRange prev = null;
 		int i = 0;
-		int size = ioMap.size();
-		for (Map.Entry e : ioMap.entrySet()) {
-			MemoryRange cur = (MemoryRange)e.getKey();
+		int length = devices.size();
+		for (Device d : devices) {
+			MemoryRange cur = d.getMemoryRange();
 			if (i == 0) {
-				// If the first entry doesn't start at MEMORY_BOTTOM, return false.
-				if (cur.getStartAddress() != MEMORY_BOTTOM) { return false; }
-			} else if (i < size - 1) {
+				// If the first entry doesn't start at 'bottom', return false.
+				if (cur.getStartAddress() != bottom) { return false; }
+			}
+
+			if (prev != null && i < length - 1) {
 				// Otherwise, compare previous map's end against this map's
 				// top.  They must be adjacent!
 				if (cur.getStartAddress() - 1 != prev.getEndAddress()) {
 					return false;
 				}
-			} else {
-				// If the last entry doesn't end at MEMORY_TOP, return false;
-				if (cur.getEndAddress() != MEMORY_TOP) { return false; }
 			}
+
+			if (i == length - 1) {
+				// If the last entry doesn't end at top, return false;
+				if (cur.getEndAddress() != top) { return false; }
+			}
+
 			i++;
 			prev = cur;
 		}
@@ -66,10 +86,8 @@ public class AddressDecoder {
 		return true;
 	}
 
-	/**
-	 * Returns true if there are any gap in the memory map.
-	 */
-	public boolean hasGaps() {
-		return !isComplete();
+	public List getDevices() {
+		// Expose a copy of the device list, not the original
+		return new ArrayList(devices);
 	}
 }

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

@@ -9,14 +9,22 @@ public abstract class Device {
 	/** The memory range for this device. */
 	private MemoryRange memoryRange;
 
+	private String name;
+
 	/** Reference to the CPU, for interrupts. */
 	private Cpu cpu;
 
-	public Device(MemoryRange range, Cpu cpu) {
-		this.memoryRange = range;
+	public Device(int address, int size, String name, Cpu cpu)
+		    throws MemoryRangeException {
+		this.memoryRange = new MemoryRange(address, address + size - 1);
+		this.name = name;
 		this.cpu = cpu;
 	}
 
+	public abstract void write(int address, int data);
+
+	public abstract int read(int address);
+
 	public MemoryRange getMemoryRange() {
 		return memoryRange;
 	}
@@ -29,12 +37,12 @@ public abstract class Device {
 		return memoryRange.getStartAddress();
 	}
 
-	public void generateInterrupt() {
-		cpu.interrupt();
+	public String getName() {
+		return name;
 	}
 
-	public void generateNonMaskableInterrupt() {
-		cpu.nmiInterrupt();
+	public void setName(String name) {
+		this.name = name;
 	}
 
 }

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

@@ -58,4 +58,12 @@ public class MemoryRange implements Comparable<MemoryRange> {
 		Integer thatStartAddr = new Integer(other.getStartAddress());
 		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();
+	}
 }

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

@@ -3,7 +3,7 @@ package com.loomcom.lm6502;
 /**
  * Exception that will be thrown if devices conflict in the IO map.
  */
-class MemoryRangeException extends Exception {
+public class MemoryRangeException extends Exception {
 	public MemoryRangeException(String msg) {
 		super(msg);
 	}

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

@@ -0,0 +1,27 @@
+package com.loomcom.lm6502.devices;
+
+import com.loomcom.lm6502.*;
+
+public class Memory extends Device {
+
+	private boolean readOnly;
+
+	public Memory(int address, int size, Cpu cpu, boolean readOnly)
+		    throws MemoryRangeException {
+		super(address, size, "RW Memory", cpu);
+		this.readOnly = readOnly;
+	}
+
+	public Memory(int address, int size, Cpu cpu)
+		    throws MemoryRangeException {
+		this(address, size, cpu, false);
+	}
+
+	public void write(int address, int data) {
+	}
+
+	public int read(int address) {
+		return 0;
+	}
+
+}