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Combined CPX, CPY, CMP into one internal operation. Closes #11.

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This commit is contained in:
Mike Naberezny 2009-08-16 12:24:26 -07:00
parent 2c1614c82c
commit f1c27198b2
1 changed files with 18 additions and 38 deletions
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56
src/py65/devices/mpu6502.py
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@ -343,32 +343,12 @@ class MPU:
def opSTX(self, y):
self.memory[y()] = self.x
def opCPY(self, x):
tbyte=self.ByteAt(x())
def opCMPR(self, get_address, register_value):
tbyte = self.ByteAt(get_address())
self.flags &= ~(self.CARRY+self.ZERO+self.NEGATIVE)
if self.y == tbyte:
if register_value == tbyte:
self.flags |= self.CARRY + self.ZERO
elif self.y > tbyte:
self.flags |= self.CARRY
else:
self.flags |= self.NEGATIVE
def opCPX(self, y):
tbyte = self.ByteAt(y())
self.flags &=~(self.CARRY+self.ZERO+self.NEGATIVE)
if self.x == tbyte:
self.flags |= self.CARRY + self.ZERO
elif self.x > tbyte:
self.flags |= self.CARRY
else:
self.flags |= self.NEGATIVE
def opCMP(self, x):
tbyte = self.ByteAt(x())
self.flags &= ~(self.CARRY+self.ZERO+self.NEGATIVE)
if self.a == tbyte:
self.flags |= self.CARRY + self.ZERO
elif self.a > tbyte:
elif register_value > tbyte:
self.flags |= self.CARRY
else:
self.flags |= self.NEGATIVE
@ -1028,22 +1008,22 @@ class MPU:
@instruction(name="CPY", mode="imm", cycles=2)
def inst_0xc0(self):
self.opCPY(self.ProgramCounter)
self.opCMPR(self.ProgramCounter, self.y)
self.pc += 1
@instruction(name="CMP", mode="inx", cycles=6)
def inst_0xc1(self):
self.opCMP(self.IndirectXAddr)
self.opCMPR(self.IndirectXAddr, self.a)
self.pc += 1
@instruction(name="CPY", mode="zpg", cycles=3)
def inst_0xc4(self):
self.opCPY(self.ZeroPageAddr)
self.opCMPR(self.ZeroPageAddr, self.y)
self.pc += 1
@instruction(name="CMP", mode="zpg", cycles=3)
def inst_0xc5(self):
self.opCMP(self.ZeroPageAddr)
self.opCMPR(self.ZeroPageAddr, self.a)
self.pc += 1
@instruction(name="DEC", mode="zpg", cycles=5)
@ -1059,7 +1039,7 @@ class MPU:
@instruction(name="CMP", mode="imm", cycles=2)
def inst_0xc9(self):
self.opCMP(self.ProgramCounter)
self.opCMPR(self.ProgramCounter, self.a)
self.pc +=1
@instruction(name="DEX", mode="imp", cycles=2)
@ -1070,12 +1050,12 @@ class MPU:
@instruction(name="CPY", mode="abs", cycles=4)
def inst_0xcc(self):
self.opCPY(self.AbsoluteAddr)
self.opCMPR(self.AbsoluteAddr, self.y)
self.pc += 2
@instruction(name="CMP", mode="abs", cycles=4)
def inst_0xcd(self):
self.opCMP(self.AbsoluteAddr)
self.opCMPR(self.AbsoluteAddr, self.a)
self.pc += 2
@instruction(name="DEC", mode="abs", cycles=3)
@ -1089,12 +1069,12 @@ class MPU:
@instruction(name="CMP", mode="iny", cycles=5, extracycles=1)
def inst_0xd1(self):
self.opCMP(self.IndirectYAddr)
self.opCMPR(self.IndirectYAddr, self.a)
self.pc += 1
@instruction(name="CMP", mode="zpx", cycles=4)
def inst_0xd5(self):
self.opCMP(self.ZeroPageXAddr)
self.opCMPR(self.ZeroPageXAddr, self.a)
self.pc += 1
@instruction(name="DEC", mode="zpx", cycles=6)
@ -1108,12 +1088,12 @@ class MPU:
@instruction(name="CMP", mode="aby", cycles=4, extracycles=1)
def inst_0xd9(self):
self.opCMP(self.AbsoluteYAddr)
self.opCMPR(self.AbsoluteYAddr, self.a)
self.pc += 2
@instruction(name="CMP", mode="abx", cycles=4, extracycles=1)
def inst_0xdd(self):
self.opCMP(self.AbsoluteXAddr)
self.opCMPR(self.AbsoluteXAddr, self.a)
self.pc += 2
@instruction(name="DEC", mode="abx", cycles=7)
@ -1123,7 +1103,7 @@ class MPU:
@instruction(name="CPX", mode="imm", cycles=2)
def inst_0xe0(self):
self.opCPX(self.ProgramCounter)
self.opCMPR(self.ProgramCounter, self.x)
self.pc += 1
@instruction(name="SBC", mode="inx", cycles=6)
@ -1133,7 +1113,7 @@ class MPU:
@instruction(name="CPX", mode="zpg", cycles=3)
def inst_0xe4(self):
self.opCPX(self.ZeroPageAddr)
self.opCMPR(self.ZeroPageAddr, self.x)
self.pc += 1
@instruction(name="SBC", mode="zpg", cycles=3)
@ -1163,7 +1143,7 @@ class MPU:
@instruction(name="CPX", mode="abs", cycles=4)
def inst_0xec(self):
self.opCPX(self.AbsoluteAddr)
self.opCMPR(self.AbsoluteAddr, self.x)
self.pc += 2
@instruction(name="SBC", mode="abs", cycles=4)