lloeki/python-dcpu_16
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refactored opcode dispatching

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Loic Nageleisen 2012-04-09 15:13:15 +02:00
parent 037559160f
commit 605790257f
1 changed files with 28 additions and 24 deletions
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52
dcpu_16.py
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@ -11,8 +11,8 @@ wmask = 2**w - 1
literals = [l for l in xrange(0, 0x20)] literals = [l for l in xrange(0, 0x20)]
opcode_map = {} _opcode_map = {}
valcode_map = {} _valcode_map = {}
class opcode(object): class opcode(object):
@ -22,7 +22,12 @@ class opcode(object):
def __call__(self, f): def __call__(self, f):
_opcode_f = f _opcode_f = f
_opcode_f.opcode = self.opcode _opcode_f.opcode = self.opcode
opcode_map[self.opcode] = _opcode_f if len(self.opcode) == 1:
_opcode_map[self.opcode[0]] = _opcode_f
else:
if not self.opcode[0] in _opcode_map.keys():
_opcode_map[self.opcode[0]] = {}
_opcode_map[self.opcode[0]][self.opcode[1]] = _opcode_f
return _opcode_f return _opcode_f
@ -36,10 +41,10 @@ class valcode(object):
try: try:
for code in self.valcode: for code in self.valcode:
# currify with (bound) code # currify with (bound) code
valcode_map[code] = lambda c, code=code: _valcode_f(c, code) _valcode_map[code] = lambda c, code=code: _valcode_f(c, code)
valcode_map[code].__name__ = '%s(code=0x%02X)' % (_valcode_f.__name__, code) _valcode_map[code].__name__ = '%s(code=0x%02X)' % (_valcode_f.__name__, code)
except TypeError: except TypeError:
valcode_map[self.valcode] = _valcode_f _valcode_map[self.valcode] = _valcode_f
return _valcode_f return _valcode_f
@ -365,12 +370,26 @@ class CPU(object):
c.r[7] = val c.r[7] = val
def _op(c, word): def _op(c, word):
"""dispatch to op""" """dispatch word to op and args"""
opcode = word & 0xF
a_code = word >> 4 & 0x3F
b_code = word >> 10 & 0x3F
try:
op = _opcode_map[opcode]
try:
op = op[a_code]
args = (c._pointer(b_code),)
except TypeError:
args = (c._pointer(a_code),
c._pointer(b_code))
except KeyError:
raise Exception('Invalid opcode %s at PC=%04X' % (["%02X"%x for x in opcode], c.pc))
return op, args
def _pointer(c, code): def _pointer(c, code):
"""get pointer to valcode""" """get pointer to valcode"""
try: try:
return valcode_map[code](c) return _valcode_map[code](c)
except KeyError: except KeyError:
raise Exception("Invalid valcode") raise Exception("Invalid valcode")
@ -386,22 +405,7 @@ class CPU(object):
"""start handling [PC]""" """start handling [PC]"""
word = c.m[c.pc] word = c.m[c.pc]
c.pc = (c.pc + 1) & wmask c.pc = (c.pc + 1) & wmask
if (word & 0xF) > 0: op, args = c._op(word)
opcode = (word & 0xF,)
a = c._pointer(word >> 4 & 0x3F)
b = c._pointer(word >> 10 & 0x3F)
args = (a, b)
elif (word >> 4 & 0x3F) > 0:
opcode = (0x0, word >> 4 & 0x3F)
a = c._pointer(word >> 10 & 0x3F)
args = (a, )
else:
raise Exception('Invalid opcode %s at PC=%04X' % (["%02X"%x for x in opcode], c.pc))
try:
op = opcode_map[opcode]
if c.debug: log(op.__name__)
except KeyError:
raise Exception('Invalid opcode %s at PC=%04X' % (["%02X"%x for x in opcode], c.pc))
if c.skip: if c.skip:
c.skip = False c.skip = False
if c.debug: log("Skipped") if c.debug: log("Skipped")