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Use bitwise OR for flag updates

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This commit is contained in:
Mike Naberezny 2014-01-25 15:39:04 -08:00
parent 806bed0a80
commit f99e063a1c
1 changed files with 13 additions and 13 deletions
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26
py65/devices/mpu6502.py
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@ -176,7 +176,7 @@ class MPU:
return z
def FlagsNZ(self, value):
self.p &= ~(self.ZERO + self.NEGATIVE)
self.p &= ~(self.ZERO | self.NEGATIVE)
if value == 0:
self.p |= self.ZERO
else:
@ -195,7 +195,7 @@ class MPU:
addr = x()
tbyte = self.ByteAt(addr)
self.p &= ~(self.CARRY + self.NEGATIVE + self.ZERO)
self.p &= ~(self.CARRY | self.NEGATIVE | self.ZERO)
if tbyte & self.NEGATIVE:
self.p |= self.CARRY
@ -218,7 +218,7 @@ class MPU:
addr = x()
tbyte = self.ByteAt(addr)
self.p &= ~(self.CARRY + self.NEGATIVE + self.ZERO)
self.p &= ~(self.CARRY | self.NEGATIVE | self.ZERO)
self.p |= tbyte & 1
tbyte = tbyte >> 1
@ -256,10 +256,10 @@ class MPU:
def opBIT(self, x):
tbyte = self.ByteAt(x())
self.p &= ~(self.ZERO + self.NEGATIVE + self.OVERFLOW)
self.p &= ~(self.ZERO | self.NEGATIVE | self.OVERFLOW)
if (self.a & tbyte) == 0:
self.p |= self.ZERO
self.p |= tbyte & (self.NEGATIVE + self.OVERFLOW)
self.p |= tbyte & (self.NEGATIVE | self.OVERFLOW)
def opROL(self, x):
if x is None:
@ -315,7 +315,7 @@ class MPU:
# the final A contents will be decimally adjusted
nibble0 = (nibble0 + adjust0) & 0xf
nibble1 = (nibble1 + adjust1) & 0xf
self.p &= ~(self.CARRY + self.OVERFLOW + self.NEGATIVE + self.ZERO)
self.p &= ~(self.CARRY | self.OVERFLOW | self.NEGATIVE | self.ZERO)
if aluresult == 0:
self.p |= self.ZERO
else:
@ -331,7 +331,7 @@ class MPU:
else:
tmp = 0
result = data + self.a + tmp
self.p &= ~(self.CARRY + self.OVERFLOW + self.NEGATIVE + self.ZERO)
self.p &= ~(self.CARRY | self.OVERFLOW | self.NEGATIVE | self.ZERO)
if (~(self.a ^ data) & (self.a ^ result)) & self.NEGATIVE:
self.p |= self.OVERFLOW
data = result
@ -379,9 +379,9 @@ class MPU:
def opCMPR(self, get_address, register_value):
tbyte = self.ByteAt(get_address())
self.p &= ~(self.CARRY + self.ZERO + self.NEGATIVE)
self.p &= ~(self.CARRY | self.ZERO | self.NEGATIVE)
if register_value == tbyte:
self.p |= self.CARRY + self.ZERO
self.p |= self.CARRY | self.ZERO
elif register_value > tbyte:
self.p |= self.CARRY
self.p |= (register_value - tbyte) & self.NEGATIVE
@ -415,7 +415,7 @@ class MPU:
nibble0 = (aluresult + adjust0) & 0xf
nibble1 = ((aluresult + adjust1) >> 4) & 0xf
self.p &= ~(self.CARRY + self.ZERO + self.NEGATIVE + self.OVERFLOW)
self.p &= ~(self.CARRY | self.ZERO | self.NEGATIVE | self.OVERFLOW)
if aluresult == 0:
self.p |= self.ZERO
else:
@ -432,7 +432,7 @@ class MPU:
borrow = 1
result = self.a + (~data & self.byteMask) + (self.p & self.CARRY)
self.p &= ~(self.CARRY + self.ZERO + self.OVERFLOW + self.NEGATIVE)
self.p &= ~(self.CARRY | self.ZERO | self.OVERFLOW | self.NEGATIVE)
if ((self.a ^ data) & (self.a ^ result)) & self.NEGATIVE:
self.p |= self.OVERFLOW
data = result & self.byteMask
@ -450,7 +450,7 @@ class MPU:
addr = x()
tbyte = self.ByteAt(addr)
self.p &= ~(self.ZERO + self.NEGATIVE)
self.p &= ~(self.ZERO | self.NEGATIVE)
tbyte = (tbyte - 1) & self.byteMask
if tbyte:
self.p |= tbyte & self.NEGATIVE
@ -469,7 +469,7 @@ class MPU:
addr = x()
tbyte = self.ByteAt(addr)
self.p &= ~(self.ZERO + self.NEGATIVE)
self.p &= ~(self.ZERO | self.NEGATIVE)
tbyte = (tbyte + 1) & self.byteMask
if tbyte:
self.p |= tbyte & self.NEGATIVE