mirror of
https://github.com/libretro/Mesen.git
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153 lines
3.5 KiB
C++
153 lines
3.5 KiB
C++
#pragma once
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#include "stdafx.h"
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#include "BaseMapper.h"
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#include "CPU.h"
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#include "MemoryManager.h"
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class Mapper83 : public BaseMapper
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{
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uint8_t _regs[11];
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uint8_t _exRegs[4];
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bool _is2kBank;
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bool _isNot2kBank;
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uint8_t _mode;
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uint8_t _bank;
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uint16_t _irqCounter;
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bool _irqEnabled;
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uint8_t _resetBit;
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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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virtual bool AllowRegisterRead() override { return true; }
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void InitMapper() override
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{
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memset(_regs, 0, sizeof(_regs));
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memset(_exRegs, 0, sizeof(_exRegs));
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_is2kBank = false;
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_isNot2kBank = false;
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_mode = 0;
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_bank = 0;
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_irqCounter = 0;
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_irqEnabled = false;
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_resetBit = 0;
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AddRegisterRange(0x5000, 0x5000, MemoryOperation::Read);
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AddRegisterRange(0x5100, 0x5103, MemoryOperation::Any);
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RemoveRegisterRange(0x8000, 0xFFFF, MemoryOperation::Read);
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UpdateState();
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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> regs{ _regs, 11 };
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ArrayInfo<uint8_t> exRegs{ _exRegs, 4 };
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Stream(regs, exRegs, _is2kBank, _isNot2kBank, _mode, _bank, _irqCounter, _irqEnabled, _resetBit);
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}
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void Reset(bool softReset) override
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{
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if(softReset) {
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_resetBit ^= 1;
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}
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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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if(_irqCounter == 0) {
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_irqEnabled = false;
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_irqCounter = 0xFFFF;
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CPU::SetIRQSource(IRQSource::External);
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}
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}
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}
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void UpdateState()
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{
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switch(_mode & 0x03) {
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case 0: SetMirroringType(MirroringType::Vertical); break;
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case 1: SetMirroringType(MirroringType::Horizontal); break;
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case 2: SetMirroringType(MirroringType::ScreenAOnly); break;
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case 3: SetMirroringType(MirroringType::ScreenBOnly); break;
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}
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if(_is2kBank && !_isNot2kBank) {
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SelectChrPage2x(0, _regs[0] << 1);
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SelectChrPage2x(1, _regs[1] << 1);
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SelectChrPage2x(2, _regs[6] << 1);
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SelectChrPage2x(3, _regs[7] << 1);
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} else {
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for(int i = 0; i < 8; i++) {
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SelectCHRPage(i, _regs[i] | ((_bank & 0x30) << 4));
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}
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}
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if(_mode & 0x40) {
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SelectPrgPage2x(0, (_bank & 0x3F) << 1);
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SelectPrgPage2x(1, ((_bank & 0x30) | 0x0F) << 1);
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} else {
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SelectPRGPage(0, _regs[8]);
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SelectPRGPage(1, _regs[9]);
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SelectPRGPage(2, _regs[10]);
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SelectPRGPage(3, -1);
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}
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}
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uint8_t ReadRegister(uint16_t addr) override
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{
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if(addr == 0x5000) {
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return (MemoryManager::GetOpenBus() & 0xFC) | _resetBit;
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} else {
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return _exRegs[addr & 0x03];
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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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if(addr < 0x8000) {
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_exRegs[addr & 0x03] = value;
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} else if(addr >= 0x8300 && addr <= 0x8302) {
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_mode &= 0xBF;
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_regs[addr - 0x8300 + 8] = value;
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UpdateState();
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} else if(addr >= 0x8310 && addr <= 0x8317) {
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_regs[addr - 0x8310] = value;
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if(addr >= 0x8312 && addr <= 0x8315) {
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_isNot2kBank = true;
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}
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UpdateState();
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} else {
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switch(addr) {
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case 0x8000: _is2kBank = true; //no break
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case 0xB000: case 0xB0FF: case 0xB1FF:
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// Dragon Ball Z Party [p1] BMC
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_bank = value;
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_mode |= 0x40;
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UpdateState();
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break;
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case 0x8100:
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_mode = value | (_mode & 0x40);
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UpdateState();
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break;
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case 0x8200:
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_irqCounter = (_irqCounter & 0xFF00) | value;
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CPU::ClearIRQSource(IRQSource::External);
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break;
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case 0x8201:
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_irqEnabled = (_mode & 0x80) == 0x80;
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_irqCounter = (_irqCounter & 0xFF) | (value << 8);
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break;
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}
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}
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}
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};
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