Bug Fixes and Copyright Date Change

The simulator now passes Klaus Dormann's 6502 Functional Test suite for
the first time.

Bug Fixes:

- PHP was not correctly setting the Break bit on the stack copy of the
  processor status, so subsequent PLA's would not set the Break status
  flag.

- The CPU had swapped NMI and IRQ reset vectors, so RTI was failing.

- BRK was pushing PC + 2 onto the stack, instead of PC + 1

- (Zero Page,X) addressing mode did not correctly wrap on zero page
  boundaries.

- The instruction table used for disassembly had addressing modes
  of LDA $B9 and $BD reversed. This did not affect behavior, only
  disassembly of these instructions.

Other:

- Updated copyright date for 2013.

- Started migrating old JUnit 3 style tests to JUnit 4 annotations.

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

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008-2012 Seth J. Morabito <sethm@loomcom.com>
+ * Copyright (c) 2008-2013 Seth J. Morabito <sethm@loomcom.com>
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
@@ -451,9 +451,9 @@ public class Simulator implements Observer {
             });
 
             try {
-                while (isRunning && !(preferences.getHaltOnBreak() && cpu.getBreakFlag())) {
+                do {
                     step();
-                }
+                } while (shouldContinue());
             } catch (SymonException ex) {
                 logger.log(Level.SEVERE, "Exception in main simulator run thread. Exiting run.");
                 ex.printStackTrace();
@@ -475,6 +475,15 @@ public class Simulator implements Observer {
 
             isRunning = false;
         }
+
+        /**
+         * 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);
+        }
     }
 
     class LoadProgramAction extends AbstractAction {