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Adding 16-bit Arithmetic Operations

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Melefo
2020-02-25 19:00:02 +01:00
parent a0f53ebd70
commit ebc3df354b
5 changed files with 188 additions and 2 deletions
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sources/APU/Instructions/16bitArithmetic.cpp
+77
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@@ -0,0 +1,77 @@
//
// Created by Melefo on 25/02/2020.
//
#include "../APU.hpp"
namespace ComSquare::APU
{
int APU::INCW(uint24_t addr)
{
uint24_t addr2 = addr + 1 + (this->_internalRegisters.p ? 0x0100 : 0);
uint16_t value = ((this->_internalRead(addr2) << 8u) | this->_internalRead(addr)) + 1u;
this->_internalWrite(addr, value);
this->_internalWrite(addr2, value >> 8u);
this->_internalRegisters.n = value & 0x8000u;
this->_internalRegisters.z = !value;
return 6;
}
int APU::DECW(uint24_t addr)
{
uint24_t addr2 = addr + 1 + (this->_internalRegisters.p ? 0x0100 : 0);
uint16_t value = ((this->_internalRead(addr2) << 8u) | this->_internalRead(addr)) - 1u;
this->_internalWrite(addr, value);
this->_internalWrite(addr2, value >> 8u);
this->_internalRegisters.n = value & 0x8000u;
this->_internalRegisters.z = !value;
return 6;
}
int APU::ADDW(uint24_t addr)
{
uint24_t addr2 = addr + 1 + (this->_internalRegisters.p ? 0x0100 : 0);
uint16_t value = ((this->_internalRead(addr2) << 8u) | this->_internalRead(addr));
uint24_t result = this->_internalRegisters.ya + value;
this->_internalRegisters.v = (~(this->_internalRegisters.ya ^ value) & (this->_internalRegisters.ya ^ result)) & 0x8000u;
this->_internalRegisters.c = result > 0xFFFFu;
this->_internalRegisters.h = ((this->_internalRegisters.ya & 0x0FFFu) + (value & 0x0FFFu)) > 0x0FFFu;
this->_internalRegisters.z = !result;
this->_internalRegisters.n = result & 0x8000u;
this->_internalRegisters.ya = result;
return 5;
}
int APU::SUBW(uint24_t addr)
{
uint24_t addr2 = addr + 1 + (this->_internalRegisters.p ? 0x0100 : 0);
uint16_t value = ((this->_internalRead(addr2) << 8u) | this->_internalRead(addr));
uint24_t result = this->_internalRegisters.ya - value;
uint16_t tmp = ((this->_internalRegisters.ya & 0x0F00u) - (value & 0x0F00u)) >> 8u;
if ((this->_internalRegisters.ya & 0x00FFu) < (value & 0x00FFu))
tmp--;
this->_internalRegisters.v = ((this->_internalRegisters.ya ^ value) & (this->_internalRegisters.ya ^ result)) & 0x8000u;
this->_internalRegisters.c = result <= 0xFFFFu;
this->_internalRegisters.h = tmp <= 0x000F;
this->_internalRegisters.z = !result;
this->_internalRegisters.n = result & 0x8000u;
this->_internalRegisters.ya = result;
return 5;
}
int APU::CMPW(uint24_t addr)
{
uint24_t addr2 = addr + 1 + (this->_internalRegisters.p ? 0x0100 : 0);
uint16_t value = ((this->_internalRead(addr2) << 8u) | this->_internalRead(addr));
uint24_t result = this->_internalRegisters.ya - value;
this->_internalRegisters.z = !result;
this->_internalRegisters.n = result & 0x8000u;
this->_internalRegisters.c = this->_internalRegisters.ya >= value;
return 4;
}
}