mirror of
https://github.com/SourMesen/Mesen2.git
synced 2025-04-02 10:21:44 -04:00
84 lines
1.8 KiB
C++
84 lines
1.8 KiB
C++
#pragma once
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#include "pch.h"
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#include "NES/BaseMapper.h"
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#include "NES/NesConsole.h"
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#include "NES/NesCpu.h"
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class Mapper43 : public BaseMapper
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{
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private:
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uint8_t _reg = 0;
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bool _swap = false;
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uint16_t _irqCounter = 0;
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bool _irqEnabled = false;
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protected:
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uint16_t GetPrgPageSize() override { return 0x2000; }
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uint16_t GetChrPageSize() override { return 0x2000; }
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uint16_t RegisterStartAddress() override { return 0x4020; }
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uint16_t RegisterEndAddress() override { return 0xFFFF; }
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bool EnableCpuClockHook() override { return true; }
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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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_swap = false;
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_reg = 0;
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UpdateState();
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SetCpuMemoryMapping(0x5000, 0x5FFF, 8, PrgMemoryType::PrgRom);
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SelectPrgPage(0, 1);
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SelectPrgPage(1, 0);
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SelectChrPage(0, 0);
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}
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void Serialize(Serializer& s) override
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{
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BaseMapper::Serialize(s);
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SV(_irqCounter);
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SV(_irqEnabled);
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SV(_reg);
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SV(_swap);
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if(!s.IsSaving()) {
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UpdateState();
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}
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}
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void ProcessCpuClock() override
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{
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BaseProcessCpuClock();
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if(_irqEnabled) {
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_irqCounter++;
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if(_irqCounter >= 4096) {
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_irqEnabled = false;
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_console->GetCpu()->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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SetCpuMemoryMapping(0x6000, 0x7FFF, _swap ? 0 : 2, PrgMemoryType::PrgRom);
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SelectPrgPage(2, _reg);
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SelectPrgPage(3, _swap ? 8 : 9);
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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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int lut[8] = { 4, 3, 5, 3, 6, 3, 7, 3 };
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switch(addr & 0xF1FF) {
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case 0x4022: _reg = lut[value & 0x07]; UpdateState(); break;
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case 0x4120: _swap = value & 0x01; UpdateState(); break;
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case 0x8122:
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case 0x4122:
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_irqEnabled = (value & 0x01) == 0x01;
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_console->GetCpu()->ClearIrqSource(IRQSource::External);
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_irqCounter = 0;
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break;
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}
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}
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};
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