mirror of
https://github.com/libretro/Mesen.git
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90 lines
2.0 KiB
C++
90 lines
2.0 KiB
C++
#pragma once
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#include "MMC1.h"
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class MMC1_105 : public MMC1
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{
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private:
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uint8_t _initState;
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uint32_t _irqCounter;
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bool _irqEnabled;
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protected:
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void InitMapper() override
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{
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MMC1::InitMapper();
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_initState = 0;
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_irqCounter = 0;
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_irqEnabled = false;
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_state.RegA000 |= 0x10; //Set I bit to 1
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}
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void StreamState(bool saving) override
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{
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MMC1::StreamState(saving);
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Stream(_initState, _irqCounter, _irqEnabled);
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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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_irqCounter++;
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//TODO: Counter hardcoded - should be based on dip switches
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if(_irqCounter == 0x28000000) {
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CPU::SetIRQSource(IRQSource::External);
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_irqEnabled = false;
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}
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}
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}
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void UpdateState() override
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{
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if(_initState == 0 && (_state.RegA000 & 0x10) == 0x00) {
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_initState = 1;
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} else if(_initState == 1 && _state.RegA000 & 0x10) {
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_initState = 2;
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}
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if(_state.RegA000 & 0x10) {
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_irqEnabled = false;
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_irqCounter = 0;
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CPU::ClearIRQSource(IRQSource::External);
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} else {
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_irqEnabled = true;
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}
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switch(_state.Reg8000 & 0x03) {
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case 0: SetMirroringType(MirroringType::ScreenAOnly); break;
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case 1: SetMirroringType(MirroringType::ScreenBOnly); break;
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case 2: SetMirroringType(MirroringType::Vertical); break;
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case 3: SetMirroringType(MirroringType::Horizontal); break;
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}
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if(_state.RegE000 & 0x10) {
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RemoveCpuMemoryMapping(0x6000, 0x7FFF);
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} else {
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SetCpuMemoryMapping(0x6000, 0x7FFF, 0, HasBattery() ? PrgMemoryType::SaveRam : PrgMemoryType::WorkRam);
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}
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if(_initState == 2) {
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if(_state.RegA000 & 0x08) {
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//MMC1 mode
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uint8_t prgReg = (_state.RegE000 & 0x07) | 0x08;
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if(_state.Reg8000 & 0x08) {
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if(_state.Reg8000 & 0x04) {
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SelectPRGPage(0, prgReg);
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SelectPRGPage(1, 0x0F);
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} else {
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SelectPRGPage(0, 0x08);
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SelectPRGPage(1, prgReg);
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}
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} else {
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SelectPrgPage2x(0, prgReg & 0xFE);
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}
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} else {
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SelectPrgPage2x(0, _state.RegA000 & 0x06);
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}
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} else {
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SelectPrgPage2x(0, 0);
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}
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}
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}; |