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114 lines
2.8 KiB
C++
114 lines
2.8 KiB
C++
#pragma once
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#include "stdafx.h"
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#include "BaseMapper.h"
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class Tf1201 : public BaseMapper
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{
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private:
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uint8_t _chrRegs[8];
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uint8_t _prgRegs[2];
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bool _swapPrg;
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uint8_t _irqCounter;
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uint8_t _irqReloadValue;
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int16_t _irqScaler;
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bool _irqEnabled;
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protected:
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virtual uint16_t GetPRGPageSize() override { return 0x2000; }
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virtual uint16_t GetCHRPageSize() override { return 0x400; }
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void InitMapper() override
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{
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memset(_prgRegs, 0, sizeof(_prgRegs));
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memset(_chrRegs, 0, sizeof(_chrRegs));
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_swapPrg = false;
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_irqCounter = 0;
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_irqReloadValue = 0;
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_irqScaler = 0;
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_irqEnabled = false;
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UpdateChr();
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UpdatePrg();
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}
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void StreamState(bool saving) override
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{
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BaseMapper::StreamState(saving);
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ArrayInfo<uint8_t> prgRegs{ _prgRegs, 2 };
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ArrayInfo<uint8_t> chrRegs{ _chrRegs, 2 };
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Stream(prgRegs, chrRegs, _swapPrg, _irqCounter, _irqReloadValue, _irqScaler, _irqEnabled);
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}
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void UpdateChr()
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{
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for(int i = 0; i < 8; i++) {
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SelectCHRPage(i, _chrRegs[i]);
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}
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}
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void UpdatePrg()
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{
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if(_swapPrg) {
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SelectPRGPage(0, -2);
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SelectPRGPage(2, _prgRegs[0]);
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} else {
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SelectPRGPage(0, _prgRegs[0]);
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SelectPRGPage(2, -2);
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}
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SelectPRGPage(1, _prgRegs[1]);
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SelectPRGPage(3, -1);
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}
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void ProcessCpuClock() override
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{
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if(_irqEnabled) {
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_irqScaler -= 3;
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if(_irqScaler <= 0) {
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_irqScaler += 341;
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_irqCounter++;
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if(_irqCounter == 0) {
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CPU::SetIRQSource(IRQSource::External);
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}
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}
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}
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}
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void WriteRegister(uint16_t addr, uint8_t value) override
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{
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addr = (addr & 0xF003) | ((addr & 0x0C) >> 2);
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if(addr >= 0xB000 && addr <= 0xE003) {
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int slot = (((addr >> 11) - 6) | (addr & 0x01)) & 0x07;
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int shift = ((addr & 0x02) << 1);
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_chrRegs[slot] = (_chrRegs[slot] & (0xF0 >> shift)) | ((value & 0x0F) << shift);
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UpdateChr();
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} else {
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switch(addr & 0xF003) {
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case 0x8000: _prgRegs[0] = value; UpdatePrg(); break;
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case 0xA000: _prgRegs[1] = value; UpdatePrg(); break;
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case 0x9000: SetMirroringType(value & 0x01 ? MirroringType::Horizontal : MirroringType::Vertical); break;
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case 0x9001: _swapPrg = (value & 0x03) != 0; UpdatePrg(); break;
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case 0xF000: _irqReloadValue = (_irqReloadValue & 0xF0) | (value & 0x0F); break;
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case 0xF002: _irqReloadValue = (_irqReloadValue & 0x0F) | (value << 4); break;
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case 0xF001:
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//VRC-like IRQs? This seems to make more sense than A12-based IRQs
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//considering FCEUX/puNES both adjust the counter value based on when
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//on the screen the IRQ is enabled.
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//This still some glitches on the screen, but relatively minor ones.
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_irqEnabled = (value & 0x02) == 0x02;
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if(_irqEnabled) {
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_irqScaler = 341;
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_irqCounter = _irqReloadValue;
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}
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CPU::ClearIRQSource(IRQSource::External);
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break;
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case 0xF003:
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CPU::ClearIRQSource(IRQSource::External);
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break;
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}
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}
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}
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}; |