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Implementing TRB

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This commit is contained in:
Anonymus Raccoon
2020-05-13 17:04:14 +02:00
parent 4c4cc6b655
commit b29d1c4216
3 changed files with 60 additions and 2 deletions
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21
sources/CPU/Instructions/BitsInstructions.cpp
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@@ -28,6 +28,27 @@ namespace ComSquare::CPU
return cycles;
}
int CPU::TRB(uint24_t valueAddr, AddressingMode mode)
{
uint16_t value = this->_bus->read(valueAddr);
if (!this->_registers.p.m)
value += this->_bus->read(valueAddr + 1) << 8u;
uint16_t newValue = value & ~this->_registers.a;
this->_bus->write(valueAddr, newValue);
if (!this->_registers.p.m)
this->_bus->write(valueAddr + 1, newValue >> 8u);
this->_registers.p.z = (value & this->_registers.a) == 0;
int cycles = 0;
if (!this->_registers.p.m)
cycles += 2;
if (mode == DirectPage)
cycles += this->_registers.dl != 0;
return cycles;
}
int CPU::BIT(uint24_t valueAddr, AddressingMode mode)
{
unsigned negativeMask = this->_registers.p.m ? 0x80u : 0x8000u;