mirror of
https://github.com/libretro/Mesen.git
synced 2024-11-23 09:09:45 +00:00
91 lines
2.7 KiB
C++
91 lines
2.7 KiB
C++
#pragma once
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#include "MMC3.h"
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class MMC3_219 : public MMC3
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{
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private:
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uint8_t _exRegs[3];
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protected:
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void InitMapper() override
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{
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MMC3::InitMapper();
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AddRegisterRange(0x5000, 0x5FFF);
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}
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void Reset(bool softreset) override
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{
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_exRegs[0] = _exRegs[2] = 0x00;
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_exRegs[1] = 0x03;
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MMC3::UpdateState();
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}
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void SelectCHRPage(uint16_t slot, uint16_t page, ChrMemoryType memoryType = ChrMemoryType::Default) override
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{
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MMC3::SelectCHRPage(slot, (_exRegs[1] << 7) | (page & 0x7F));
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}
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void SelectPRGPage(uint16_t slot, uint16_t page, PrgMemoryType memoryType = PrgMemoryType::PrgRom) override
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{
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MMC3::SelectPRGPage(slot, (_exRegs[1] << 4) | (page & 0x0F));
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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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if(addr < 0x8000) {
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switch(addr & 0x01) {
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case 0: _exRegs[1] = (_exRegs[1] & ~0x01) | ((value >> 3) & 0x01); break;
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case 1: _exRegs[1] = (_exRegs[1] & ~0x02) | ((value >> 4) & 0x02); break;
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}
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MMC3::UpdatePrgMapping();
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MMC3::UpdateChrMapping();
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} else if(addr < 0xA000) {
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switch(addr & 0xE003) {
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case 0x8000:
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MMC3::WriteRegister(addr, value);
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break;
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case 0x8002:
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_exRegs[0] = value;
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MMC3::WriteRegister(addr, value);
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break;
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case 0x8001:
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if(_exRegs[0] & 0x20) { // Extended Mode
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uint8_t bankRegister = MMC3::GetState().Reg8000;
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if((bankRegister >= 0x25) && (bankRegister <= 0x26)) {
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uint8_t prgBank = ((value & 0x20) >> 5) | ((value & 0x10) >> 3) | ((value & 0x08) >> 1) | ((value & 0x04) << 1);
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MMC3::_registers[6 | (bankRegister & 0x01)] = prgBank;
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MMC3::UpdatePrgMapping();
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} else if((bankRegister >= 0x08) && (bankRegister <= 0x1F)) {
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switch(bankRegister) {
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case 0x08: case 0x0A: case 0x0E: case 0x12: case 0x16: case 0x1A: case 0x1E:
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_exRegs[2] = value << 4;
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break;
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case 0x09: MMC3::_registers[0] = _exRegs[2] | (value >> 1 & 0x0E); break;
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case 0x0B: MMC3::_registers[0] = _exRegs[2] | (value >> 1 | 0x1); break;
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case 0x0C:
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case 0x0D: MMC3::_registers[1] = _exRegs[2] | (value >> 1 & 0xE); break;
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case 0x0F: MMC3::_registers[1] = _exRegs[2] | (value >> 1 | 0x1); break;
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case 0x10:
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case 0x11: MMC3::_registers[2] = _exRegs[2] | (value >> 1 & 0xF); break;
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case 0x14:
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case 0x15: MMC3::_registers[3] = _exRegs[2] | (value >> 1 & 0xF); break;
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case 0x18:
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case 0x19: MMC3::_registers[4] = _exRegs[2] | (value >> 1 & 0xF); break;
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case 0x1C:
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case 0x1D: MMC3::_registers[5] = _exRegs[2] | (value >> 1 & 0xF); break;
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}
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MMC3::UpdateChrMapping();
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}
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} else { // Normal MMC3
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MMC3::WriteRegister(addr, value);
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}
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break;
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}
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} else {
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MMC3::WriteRegister(addr, value);
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}
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}
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}; |