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https://github.com/SourMesen/Mesen.git
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122 lines
2.8 KiB
C++
122 lines
2.8 KiB
C++
#pragma once
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#include "BaseMapper.h"
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#include "CPU.h"
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class FrontFareast : public BaseMapper
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{
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private:
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uint16_t _irqCounter;
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bool _irqEnabled;
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bool _ffeAltMode;
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protected:
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uint16_t GetPRGPageSize() override { return 0x2000; }
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uint16_t GetCHRPageSize() override { return 0x400; }
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uint32_t GetChrRamSize() override { return 0x8000; }
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uint16_t RegisterStartAddress() override { return 0x42FE; }
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uint16_t RegisterEndAddress() override { return 0x4517; }
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void InitMapper() override
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{
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_irqCounter = 0;
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_irqEnabled = false;
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_ffeAltMode = true;
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switch(_romInfo.MapperID) {
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case 6:
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AddRegisterRange(0x8000, 0xFFFF, MemoryOperation::Write);
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SelectPrgPage2x(0, 0);
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SelectPrgPage2x(1, 14);
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break;
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case 8:
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AddRegisterRange(0x8000, 0xFFFF, MemoryOperation::Write);
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SelectPrgPage4x(0, 0);
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break;
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case 17:
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SelectPrgPage4x(0, -4);
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break;
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}
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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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Stream(_irqCounter, _irqEnabled, _ffeAltMode);
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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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_console->GetCpu()->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 WriteRegister(uint16_t addr, uint8_t value) override
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{
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switch(addr) {
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case 0x42FE:
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_ffeAltMode = (value & 0x80) == 0x00;
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switch((value >> 4) & 0x01) {
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case 0: SetMirroringType(MirroringType::ScreenAOnly); break;
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case 1: SetMirroringType(MirroringType::ScreenBOnly); break;
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}
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break;
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case 0x42FF:
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switch((value >> 4) & 0x01) {
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case 0: SetMirroringType(MirroringType::Vertical); break;
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case 1: SetMirroringType(MirroringType::Horizontal); break;
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}
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break;
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case 0x4501:
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_irqEnabled = false;
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_console->GetCpu()->ClearIrqSource(IRQSource::External);
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break;
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case 0x4502:
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_irqCounter = (_irqCounter & 0xFF00) | value;
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_console->GetCpu()->ClearIrqSource(IRQSource::External);
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break;
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case 0x4503:
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_irqCounter = (_irqCounter & 0x00FF) | (value << 8);
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_irqEnabled = true;
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_console->GetCpu()->ClearIrqSource(IRQSource::External);
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break;
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default:
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if(_romInfo.MapperID == 6) {
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if(addr >= 0x8000) {
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if(HasChrRam() || _ffeAltMode) {
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SelectPrgPage2x(0, (value & 0xFC) >> 1);
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value &= 0x03;
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}
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SelectChrPage8x(0, value << 3);
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}
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} else if(_romInfo.MapperID == 8) {
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if(addr >= 0x8000) {
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SelectPrgPage2x(0, (value & 0xF8) >> 2);
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SelectChrPage8x(0, (value & 0x07) << 3);
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}
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} else {
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switch(addr) {
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case 0x4504: case 0x4505: case 0x4506: case 0x4507:
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SelectPRGPage(addr - 0x4504, value);
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break;
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case 0x4510: case 0x4511: case 0x4512: case 0x4513: case 0x4514: case 0x4515: case 0x4516: case 0x4517:
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SelectCHRPage(addr - 0x4510, value);
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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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};
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