Work In Progress: CPU behavior, UI changes

This is something of a "Work in Progress" checkpoint of several features
that are all half baked:

1. Allow loading of 16KB ROM files at address $C000 at run-time, not
   just at startup. See the "Load ROM..." File menu item.

2. Introduces the notion of "CPU Behaviors", so the core 6502 CPU
   implementation can match the behavior of either an early NMOS 6502, late
   NMOS 6502, or CMOS 65C02. Very little of this is actually implemented so
   far.

3. Adds a completely bogus implementation of the 6522 VIA (it
   does absolutely nothing right now).

4. Changes the address of the ACIA in the simulated system to match a
   real hardware implementation I put together.

src/main/java/com/loomcom/symon/ui/Console.java

@@ -4,6 +4,8 @@ import java.awt.event.KeyEvent;
 import java.awt.event.KeyListener;
 import java.awt.event.MouseEvent;
 import java.awt.event.MouseListener;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 
 import com.grahamedgecombe.jterminal.JTerminal;
 import com.grahamedgecombe.jterminal.vt100.Vt100TerminalModel;
@@ -21,15 +23,18 @@ import javax.swing.border.Border;
 
 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;
-    // If true, swap CR and LF characters
-    private static final boolean SWAP_CR_AND_LF = true;
+    private static final int     DEFAULT_COLUMNS      = 80;
+    private static final int     DEFAULT_ROWS         = 24;
+    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;
+    private static final boolean SEND_CR_LF_FOR_CR    = false;
 
-    private FifoRingBuffer typeAheadBuffer;
+    // If true, the console is actively listening for key input.
+    private boolean isListening;
+
+    private FifoRingBuffer<Character> typeAheadBuffer;
 
     public Console() {
         this(DEFAULT_COLUMNS, DEFAULT_ROWS);
@@ -39,7 +44,8 @@ public class Console extends JTerminal implements KeyListener, MouseListener {
         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(128);
+        this.typeAheadBuffer = new FifoRingBuffer<Character>(128);
+        this.isListening = false;
         setBorderWidth(DEFAULT_BORDER_WIDTH);
         addKeyListener(this);
         addMouseListener(this);
@@ -52,7 +58,6 @@ public class Console extends JTerminal implements KeyListener, MouseListener {
     /**
      * Reset the console. This will cause the console to be cleared and the cursor returned to the
      * home position.
-     *
      */
     public void reset() {
         typeAheadBuffer.reset();
@@ -62,6 +67,14 @@ public class Console extends JTerminal implements KeyListener, MouseListener {
         repaint();
     }
 
+    public void startListening() {
+        this.isListening = true;
+    }
+
+    public void stopListening() {
+        this.isListening = false;
+    }
+
     /**
      * Returns true if a key has been pressed since the last time input was read.
      *
@@ -77,22 +90,23 @@ public class Console extends JTerminal implements KeyListener, MouseListener {
      * @param keyEvent The key event.
      */
     public void keyTyped(KeyEvent keyEvent) {
-        char keyTyped = keyEvent.getKeyChar();
+        if (isListening) {
+            char keyTyped = keyEvent.getKeyChar();
 
-        if (SWAP_CR_AND_LF) {
-            if (keyTyped == 0x0a) {
-                keyTyped = 0x0d;
+            if (SWAP_CR_AND_LF) {
+                if (keyTyped == 0x0a) {
+                    keyTyped = 0x0d;
+                } else if (keyTyped == 0x0d) {
+                    keyTyped = 0x0a;
+                }
             }
-            else if (keyTyped == 0x0d) {
-                keyTyped = 0x0a;
-            }
-        }
 
-        if (SEND_CR_LF_FOR_CR && keyTyped == 0x0d) {
-            typeAheadBuffer.push(0x0d);
-            typeAheadBuffer.push(0x0a);
-        } else {
-            typeAheadBuffer.push(keyTyped);
+            if (SEND_CR_LF_FOR_CR && keyTyped == 0x0d) {
+                typeAheadBuffer.push((char) 0x0d);
+                typeAheadBuffer.push((char) 0x0a);
+            } else {
+                typeAheadBuffer.push(keyTyped);
+            }
         }
 
         keyEvent.consume();
@@ -113,7 +127,7 @@ public class Console extends JTerminal implements KeyListener, MouseListener {
      * @return The character typed.
      */
     public char readInputChar() throws FifoUnderrunException {
-        return (char)typeAheadBuffer.pop();
+        return typeAheadBuffer.pop();
     }
 
     /**