def bpl(self):
if not self._flag.n:
self._pc.value = self._pc.value + s8(self._data)
return True
return False
def bvs(self):
if self._flag.v:
self._pc.value = self._pc.value + s8(self._data)
return True
return False
def pre_fill(self, read_data=True):
opcode = self._bus.read(self._pc.value)
ins = self._ins[opcode]
mode = ins.addr_mode()
cross_boundry = False
if mode == AddrMode.Implied:
self._addr = -1
self._data = -1
elif mode == AddrMode.Absolute:
lo = self.fetch(1)
hi = self.fetch(2)
self._addr = u16((hi << 8) + lo)
if read_data:
self._data = self._bus.read(self._addr)
elif mode == AddrMode.Accumulator:
self._addr = -1
self._data = self._a.value
elif mode == AddrMode.Immediate:
self._addr = -1
self._data = self.fetch(1)
elif mode == AddrMode.ZeroPage:
self._addr = self.fetch(1)
if read_data:
self._data = self._bus.read(self._addr)
elif mode == AddrMode.Relative:
self._addr = -1
self._data = self.fetch(1)
prev_ = self._next_addr
next_ = self._next_addr + s8(self._data)
if (prev_ & 0xff00) != (next_ & 0xff00):
cross_boundry = True
elif mode == AddrMode.IndexedIndirectY:
addr = self.fetch(1)
lo = self._bus.read(addr)
hi = self._bus.read((addr + 1) % 256)
self._addr = u16((hi << 8) + lo + self._y.value)
if read_data:
self._data = self._bus.read(self._addr)
cross_boundry = (lo + self._y.value) > 0xff
elif mode == AddrMode.ZeroIndexedIndirectX:
index = u8(self.fetch(1) + self._x.value)
self._addr = u16(self._bus.read(index) + ((self._bus.read((index + 1) & 0xff)) << 8))
if read_data:
self._data = self._bus.read(self._addr)
elif mode == AddrMode.AbslouteIndirect:
addr = self.fetch(1) + (self.fetch(2) << 8)
if (addr & 0xff) == 0xff:
self._addr = self._bus.read(addr) + (self._bus.read(addr & 0xff00) << 8)
else:
self._addr = self._bus.read(addr) + (self._bus.read(addr + 1) << 8)
self._data = -1
elif mode == AddrMode.AbslouteIndexedY:
self._addr = u16(self._y.value + self.fetch(1) + (self.fetch(2) << 8))
if read_data:
self._data = self._bus.read(self._addr)
cross_boundry = (self._y.value + self.fetch(1) > 0xff)
elif mode == AddrMode.ZeroIndexedX:
self._addr = u8(self._x.value + self.fetch(1))
if read_data:
self._data = self._bus.read(self._addr)
elif mode == AddrMode.ZeroIndexedY:
self._addr = u8(self._y.value + self.fetch(1))
if read_data:
self._data = self._bus.read(self._addr)
elif mode == AddrMode.AbslouteIndexedX:
self._addr = u16(self._x.value + self.fetch(1) + (self.fetch(2) << 8))
if read_data:
self._data = self._bus.read(self._addr)
cross_boundry = (self._x.value + self.fetch(1) > 0xff)
else:
assert False, 'Need to impl, {}'.format(mode)
return cross_boundry