Apple-2-Tools/applepy
1
0
Fork 0
mirror of https://github.com/jtauber/applepy.git synced 2024-06-01 13:41:28 +00:00
Code Issues Projects Releases Wiki Activity

properly use 0 and 1 not False and True for flags

Browse Source
This commit is contained in:
James Tauber 2011-08-07 00:30:12 -04:00
parent 777266f8e1
commit f521fba883
1 changed files with 17 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
applepy.py
View File

@ -311,13 +311,13 @@ class CPU:
#### ####
def status_from_byte(self, status): def status_from_byte(self, status):
self.carry_flag = 0 != status & 1 self.carry_flag = [0, 1][0 != status & 1]
self.zero_flag = 0 != status & 2 self.zero_flag = [0, 1][0 != status & 2]
self.interrupt_disable_flag = 0 != status & 4 self.interrupt_disable_flag = [0, 1][0 != status & 4]
self.decimal_mode_flag = 0 != status & 8 self.decimal_mode_flag = [0, 1][0 != status & 8]
self.break_flag = 0 != status & 16 self.break_flag = [0, 1][0 != status & 16]
self.overflow_flag = 0 != status & 64 self.overflow_flag = [0, 1][0 != status & 64]
self.sign_flag = 0 != status & 128 self.sign_flag = [0, 1][0 != status & 128]
def status_as_byte(self): 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 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): def update_nz(self, value):
value = value % 0x100 value = value % 0x100
self.zero_flag = (value == 0) self.zero_flag = [0, 1][(value == 0)]
self.sign_flag = ((value & 0x80) != 0) self.sign_flag = [0, 1][((value & 0x80) != 0)]
return value return value
def update_nzc(self, value): def update_nzc(self, value):
self.carry_flag = (value > 0xFF) self.carry_flag = [0, 1][(value > 0xFF)]
return self.update_nz(value) return self.update_nz(value)
#### ####
@ -613,7 +613,7 @@ class CPU:
self.accumulator = self.update_nzc(result2) self.accumulator = self.update_nzc(result2)
# perhaps this could be calculated from result2 but result1 is more intuitive # 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): def SBC(self, operand_address):
# @@@ doesn't handle BCD yet # @@@ doesn't handle BCD yet
@ -633,10 +633,10 @@ class CPU:
result2 = a2 - m2 - [1, 0][self.carry_flag] result2 = a2 - m2 - [1, 0][self.carry_flag]
self.accumulator = self.update_nz(result2) 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 # 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 # BIT
@ -644,23 +644,23 @@ class CPU:
value = self.memory.read_byte(operand_address) value = self.memory.read_byte(operand_address)
self.sign_flag = ((value >> 7) % 2) # bit 7 self.sign_flag = ((value >> 7) % 2) # bit 7
self.overflow_flag = ((value >> 6) % 2) # bit 6 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 # COMPARISON
def CMP(self, operand_address): def CMP(self, operand_address):
result = self.accumulator - self.memory.read_byte(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) self.update_nz(result)
def CPX(self, operand_address): def CPX(self, operand_address):
result = self.x_index - self.memory.read_byte(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) self.update_nz(result)
def CPY(self, operand_address): def CPY(self, operand_address):
result = self.y_index - self.memory.read_byte(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) self.update_nz(result)
# SYSTEM # SYSTEM