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72 lines
1.2 KiB
C++
72 lines
1.2 KiB
C++
#pragma once
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#include "stdafx.h"
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#include "BaseMapper.h"
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// Bootleg copy of Batman: The Video Game
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class Mapper417 : 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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protected:
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virtual uint16_t GetPRGPageSize() override { return 0x2000; }
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virtual uint16_t GetCHRPageSize() override { return 0x0400; }
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void InitMapper() override
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{
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_irqEnabled = false;
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_irqCounter = 0;
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SelectPRGPage(3, -1);
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}
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virtual void StreamState(bool saving) override
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{
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BaseMapper::StreamState(saving);
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Stream(_irqEnabled, _irqCounter);
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}
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void ProcessCpuClock() override
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{
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_irqCounter++;
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if (_irqCounter & 0x400) {
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if (_irqEnabled) {
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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 WriteRegister(uint16_t addr, uint8_t value) override
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{
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switch ((addr >> 4) & 0x07) {
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case 0:
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SelectPRGPage(addr & 0x03, value);
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break;
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case 1:
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SelectCHRPage(addr & 0x03, value);
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break;
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case 2:
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SelectCHRPage((addr & 0x03) | 0x04, value);
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break;
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case 3:
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_irqEnabled = true;
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_irqCounter = 0;
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break;
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case 4:
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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 5:
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SetNametable(addr & 0x03, value & 0x01);
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break;
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}
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}
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};
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