Mesen2/Core/NES/Mappers/Ntdec/Tf1201.h
2024-10-01 20:57:06 +09:00

121 lines
No EOL
2.9 KiB
C++

#pragma once
#include "pch.h"
#include "NES/BaseMapper.h"
class Tf1201 : public BaseMapper
{
private:
uint8_t _chrRegs[8] = {};
uint8_t _prgRegs[2] = {};
bool _swapPrg = false;
uint8_t _irqCounter = 0;
uint8_t _irqReloadValue = 0;
int16_t _irqScaler = 0;
bool _irqEnabled = false;
protected:
uint16_t GetPrgPageSize() override { return 0x2000; }
uint16_t GetChrPageSize() override { return 0x400; }
bool EnableCpuClockHook() override { return true; }
void InitMapper() override
{
memset(_prgRegs, 0, sizeof(_prgRegs));
memset(_chrRegs, 0, sizeof(_chrRegs));
_swapPrg = false;
_irqCounter = 0;
_irqReloadValue = 0;
_irqScaler = 0;
_irqEnabled = false;
UpdateChr();
UpdatePrg();
}
void Serialize(Serializer& s) override
{
BaseMapper::Serialize(s);
SVArray(_prgRegs, 2);
SVArray(_chrRegs, 8);
SV(_swapPrg);
SV(_irqCounter);
SV(_irqReloadValue);
SV(_irqScaler);
SV(_irqEnabled);
}
void UpdateChr()
{
for(int i = 0; i < 8; i++) {
SelectChrPage(i, _chrRegs[i]);
}
}
void UpdatePrg()
{
if(_swapPrg) {
SelectPrgPage(0, -2);
SelectPrgPage(2, _prgRegs[0]);
} else {
SelectPrgPage(0, _prgRegs[0]);
SelectPrgPage(2, -2);
}
SelectPrgPage(1, _prgRegs[1]);
SelectPrgPage(3, -1);
}
void ProcessCpuClock() override
{
BaseProcessCpuClock();
if(_irqEnabled) {
_irqScaler -= 3;
if(_irqScaler <= 0) {
_irqScaler += 341;
_irqCounter++;
if(_irqCounter == 0) {
_console->GetCpu()->SetIrqSource(IRQSource::External);
}
}
}
}
void WriteRegister(uint16_t addr, uint8_t value) override
{
addr = (addr & 0xF003) | ((addr & 0x0C) >> 2);
if(addr >= 0xB000 && addr <= 0xE003) {
int slot = (((addr >> 11) - 6) | (addr & 0x01)) & 0x07;
int shift = ((addr & 0x02) << 1);
_chrRegs[slot] = (_chrRegs[slot] & (0xF0 >> shift)) | ((value & 0x0F) << shift);
UpdateChr();
} else {
switch(addr & 0xF003) {
case 0x8000: _prgRegs[0] = value; UpdatePrg(); break;
case 0xA000: _prgRegs[1] = value; UpdatePrg(); break;
case 0x9000: SetMirroringType(value & 0x01 ? MirroringType::Horizontal : MirroringType::Vertical); break;
case 0x9001: _swapPrg = (value & 0x03) != 0; UpdatePrg(); break;
case 0xF000: _irqReloadValue = (_irqReloadValue & 0xF0) | (value & 0x0F); break;
case 0xF002: _irqReloadValue = (_irqReloadValue & 0x0F) | (value << 4); break;
case 0xF001:
//VRC-like IRQs? This seems to make more sense than A12-based IRQs
//considering FCEUX/puNES both adjust the counter value based on when
//on the screen the IRQ is enabled.
//This still some glitches on the screen, but relatively minor ones.
_irqEnabled = (value & 0x02) == 0x02;
if(_irqEnabled) {
_irqScaler = 341;
_irqCounter = _irqReloadValue;
}
_console->GetCpu()->ClearIrqSource(IRQSource::External);
break;
case 0xF003:
_console->GetCpu()->ClearIrqSource(IRQSource::External);
break;
}
}
}
};