Apple-2-Tools/applepy
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properly use 0 and 1 not False and True for flags

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James Tauber 2011-08-07 00:30:12 -04:00
parent 777266f8e1
commit f521fba883
1 changed files with 17 additions and 17 deletions
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applepy.py
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@ -311,13 +311,13 @@ class CPU:
####
def status_from_byte(self, status):
self.carry_flag = 0 != status & 1
self.zero_flag = 0 != status & 2
self.interrupt_disable_flag = 0 != status & 4
self.decimal_mode_flag = 0 != status & 8
self.break_flag = 0 != status & 16
self.overflow_flag = 0 != status & 64
self.sign_flag = 0 != status & 128
self.carry_flag = [0, 1][0 != status & 1]
self.zero_flag = [0, 1][0 != status & 2]
self.interrupt_disable_flag = [0, 1][0 != status & 4]
self.decimal_mode_flag = [0, 1][0 != status & 8]
self.break_flag = [0, 1][0 != status & 16]
self.overflow_flag = [0, 1][0 != status & 64]
self.sign_flag = [0, 1][0 != status & 128]
def status_as_byte(self):
return self.carry_flag | self.zero_flag << 1 | self.interrupt_disable_flag << 2 | self.decimal_mode_flag << 3 | self.break_flag << 4 | 1 << 5 | self.overflow_flag << 6 | self.sign_flag << 7
@ -386,12 +386,12 @@ class CPU:
def update_nz(self, value):
value = value % 0x100
self.zero_flag = (value == 0)
self.sign_flag = ((value & 0x80) != 0)
self.zero_flag = [0, 1][(value == 0)]
self.sign_flag = [0, 1][((value & 0x80) != 0)]
return value
def update_nzc(self, value):
self.carry_flag = (value > 0xFF)
self.carry_flag = [0, 1][(value > 0xFF)]
return self.update_nz(value)
####
@ -613,7 +613,7 @@ class CPU:
self.accumulator = self.update_nzc(result2)
# perhaps this could be calculated from result2 but result1 is more intuitive
self.overflow_flag = (result1 > 127) | (result1 < -128)
self.overflow_flag = [0, 1][(result1 > 127) | (result1 < -128)]
def SBC(self, operand_address):
# @@@ doesn't handle BCD yet
@ -633,10 +633,10 @@ class CPU:
result2 = a2 - m2 - [1, 0][self.carry_flag]
self.accumulator = self.update_nz(result2)
self.carry_flag = (result2 >= 0)
self.carry_flag = [0, 1][(result2 >= 0)]
# perhaps this could be calculated from result2 but result1 is more intuitive
self.overflow_flag = (result1 > 127) | (result1 < -128)
self.overflow_flag = [0, 1][(result1 > 127) | (result1 < -128)]
# BIT
@ -644,23 +644,23 @@ class CPU:
value = self.memory.read_byte(operand_address)
self.sign_flag = ((value >> 7) % 2) # bit 7
self.overflow_flag = ((value >> 6) % 2) # bit 6
self.zero_flag = ((self.accumulator & value) == 0)
self.zero_flag = [0, 1][((self.accumulator & value) == 0)]
# COMPARISON
def CMP(self, operand_address):
result = self.accumulator - self.memory.read_byte(operand_address)
self.carry_flag = (result >= 0)
self.carry_flag = [0, 1][(result >= 0)]
self.update_nz(result)
def CPX(self, operand_address):
result = self.x_index - self.memory.read_byte(operand_address)
self.carry_flag = (result >= 0)
self.carry_flag = [0, 1][(result >= 0)]
self.update_nz(result)
def CPY(self, operand_address):
result = self.y_index - self.memory.read_byte(operand_address)
self.carry_flag = (result >= 0)
self.carry_flag = [0, 1][(result >= 0)]
self.update_nz(result)
# SYSTEM