Flags (P) can now be changed from the "registers" command.

CHANGES.txt

@@ -6,6 +6,10 @@ Next Release
   - Fixed that relative branch calculations would not use the correct 
     start address when assembling in the monitor.  Closes #10.
 
+  - The processor status register ("p" or "flags") can now be changed 
+    in the monitor using the "registers" command with an argument of
+    "p", such as "registers p=00".
+
 0.6 (2009-08-11)
 
   - Added monitor shortcut "a" for "assemble".

src/py65/monitor.py

@@ -295,13 +295,15 @@ class Monitor(cmd.Cmd):
             return self._output("Syntax error: %s" % args)
 
         for register, value in pairs:
-            if register not in ('pc', 'sp', 'a', 'x', 'y'):
+            if register not in ('pc', 'sp', 'a', 'x', 'y', 'p'):
                 self._output("Invalid register: %s" % register)
             else:
                 try:
                     intval = self._address_parser.number(value) & 0xFFFF
                     if len(register) == 1:
                         intval &= 0xFF
+                    if register == 'p':
+                        register = 'flags'
                     setattr(self._mpu, register, intval)
                 except KeyError, why:
                     self._output(why[0])

src/py65/tests/test_monitor.py

@@ -266,13 +266,14 @@ class MonitorTests(unittest.TestCase):
     def test_registers_updates_all_registers(self):
         stdout = StringIO()
         mon = Monitor(stdout=stdout)
-        mon.do_registers('a=42,x=43,y=44, sp=45, pc=4600')
+        mon.do_registers('a=42,x=43,y=44,p=45, sp=46, pc=4600')
         out = stdout.getvalue()
         self.assertEqual("", out)         
         self.assertEqual(0x42, mon._mpu.a)
         self.assertEqual(0x43, mon._mpu.x)
         self.assertEqual(0x44, mon._mpu.y)
-        self.assertEqual(0x45, mon._mpu.sp)
+        self.assertEqual(0x45, mon._mpu.flags)
+        self.assertEqual(0x46, mon._mpu.sp)
         self.assertEqual(0x4600, mon._mpu.pc)
 
     def test_help_registers(self):