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https://github.com/libretro/Mesen.git
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113 lines
2.5 KiB
C++
113 lines
2.5 KiB
C++
#pragma once
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#include "stdafx.h"
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#include "BaseMapper.h"
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class MMC2 : public BaseMapper
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{
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private:
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enum class MMC2Registers
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{
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RegA000 = 0xA,
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RegB000 = 0xB,
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RegC000 = 0xC,
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RegD000 = 0xD,
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RegE000 = 0xE,
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RegF000 = 0xF
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};
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protected:
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uint8_t _leftLatch;
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uint8_t _rightLatch;
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uint8_t _leftChrPage[2];
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uint8_t _rightChrPage[2];
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bool _needChrUpdate;
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virtual uint16_t GetPRGPageSize() { return 0x2000; }
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virtual uint16_t GetCHRPageSize() { return 0x1000; }
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virtual void InitMapper()
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{
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_leftLatch = 1;
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_rightLatch = 1;
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_leftChrPage[0] = 0;
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_leftChrPage[1] = 0;
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_rightChrPage[0] = 0;
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_rightChrPage[1] = 0;
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_needChrUpdate = false;
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SelectPRGPage(0, 0);
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SelectPRGPage(1, -3);
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SelectPRGPage(2, -2);
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SelectPRGPage(3, -1);
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SelectCHRPage(0, 0);
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SelectCHRPage(0, 1);
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}
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void StreamState(bool saving)
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{
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Stream<uint8_t>(_leftLatch);
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Stream<uint8_t>(_rightLatch);
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Stream<bool>(_needChrUpdate);
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StreamArray<uint8_t>(_leftChrPage, 2);
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StreamArray<uint8_t>(_rightChrPage, 2);
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BaseMapper::StreamState(saving);
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}
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void WriteRegister(uint16_t addr, uint8_t value)
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{
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switch((MMC2Registers)(addr >> 12)) {
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case MMC2Registers::RegA000:
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SelectPRGPage(0, value & 0x0F);
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break;
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case MMC2Registers::RegB000:
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_leftChrPage[0] = value & 0x1F;
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SelectCHRPage(0, _leftChrPage[_leftLatch]);
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break;
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case MMC2Registers::RegC000:
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_leftChrPage[1] = value & 0x1F;
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SelectCHRPage(0, _leftChrPage[_leftLatch]);
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break;
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case MMC2Registers::RegD000:
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_rightChrPage[0] = value & 0x1F;
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SelectCHRPage(1, _rightChrPage[_rightLatch]);
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break;
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case MMC2Registers::RegE000:
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_rightChrPage[1] = value & 0x1F;
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SelectCHRPage(1, _rightChrPage[_rightLatch]);
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break;
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case MMC2Registers::RegF000:
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SetMirroringType(((value & 0x01) == 0x01) ? MirroringType::Horizontal : MirroringType::Vertical);
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break;
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}
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}
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public:
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virtual void NotifyVRAMAddressChange(uint16_t addr)
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{
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if(_needChrUpdate) {
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SelectCHRPage(0, _leftChrPage[_leftLatch]);
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SelectCHRPage(1, _rightChrPage[_rightLatch]);
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_needChrUpdate = false;
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}
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if(addr == 0x0FD8) {
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_leftLatch = 0;
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_needChrUpdate = true;
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} else if(addr == 0x0FE8) {
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_leftLatch = 1;
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_needChrUpdate = true;
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} else if(addr >= 0x1FD8 && addr <= 0x1FDF) {
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_rightLatch = 0;
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_needChrUpdate = true;
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} else if(addr >= 0x1FE8 && addr <= 0x1FEF) {
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_rightLatch = 1;
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_needChrUpdate = true;
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}
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}
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}; |