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Cleaning up the CPX/CPY/INX/INY

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This commit is contained in:
Anonymus Raccoon
2020-04-06 17:19:04 +02:00
parent 83b8c83e6e
commit 055e7d29bd
3 changed files with 74 additions and 73 deletions
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sources/CPU/Instructions/InternalInstruction.cpp
-66
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@@ -199,72 +199,6 @@ namespace ComSquare::CPU
return 0;
}
int CPU::INX(uint24_t, AddressingMode)
{
this->_registers.x++;
if (this->_registers.p.x_b)
this->_registers.x %= 0x100;
unsigned negativeFlag = this->_registers.p.x_b ? 0x80u : 0x8000u;
this->_registers.p.z = this->_registers.x == 0;
this->_registers.p.n = this->_registers.x & negativeFlag;
return 0;
}
int CPU::INY(uint24_t, AddressingMode)
{
this->_registers.y++;
if (this->_registers.p.x_b)
this->_registers.y %= 0x100;
unsigned negativeFlag = this->_registers.p.x_b ? 0x80u : 0x8000u;
this->_registers.p.z = this->_registers.y == 0;
this->_registers.p.n = this->_registers.y & negativeFlag;
return 0;
}
int CPU::CPX(uint24_t valueAddr, AddressingMode mode)
{
unsigned value = this->_bus->read(valueAddr++);
if (this->_registers.p.x_b) {
uint8_t x = this->_registers.x;
x -= value;
this->_registers.p.z = x == 0;
this->_registers.p.n = x & 0x80u;
} else {
value += this->_bus->read(valueAddr) << 8u;
uint16_t x = this->_registers.x;
x -= value;
this->_registers.p.z = x == 0;
this->_registers.p.n = x & 0x8000u;
}
this->_registers.p.c = this->_registers.x >= value;
return !this->_registers.p.x_b + (mode == DirectPage && this->_registers.dl != 0);
}
int CPU::CPY(uint24_t valueAddr, AddressingMode mode)
{
unsigned value = this->_bus->read(valueAddr++);
this->_registers.p.c = this->_registers.y >= value;
if (this->_registers.p.x_b) {
uint8_t y = this->_registers.y;
y -= value;
this->_registers.p.z = y == 0;
this->_registers.p.n = y & 0x80u;
} else {
value += this->_bus->read(valueAddr) << 8u;
uint16_t y = this->_registers.y;
y -= value;
this->_registers.p.z = y == 0;
this->_registers.p.n = y & 0x8000u;
}
return !this->_registers.p.x_b + (mode == DirectPage && this->_registers.dl != 0);
}
int CPU::BCC(uint24_t valueAddr, AddressingMode)
{
if (!this->_registers.p.c)