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73 lines
1.6 KiB
C++
73 lines
1.6 KiB
C++
#pragma once
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#include "stdafx.h"
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#include "BaseMapper.h"
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#include "A12Watcher.h"
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#include "CPU.h"
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class Mapper35 : public BaseMapper
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{
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private:
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uint8_t _irqCounter;
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bool _irqEnabled;
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A12Watcher _a12Watcher;
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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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void StreamState(bool saving) override
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{
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BaseMapper::StreamState(saving);
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SnapshotInfo a12Watcher{ &_a12Watcher };
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Stream(_irqCounter, _irqEnabled, a12Watcher);
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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 & 0xF007) {
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case 0x8000: case 0x8001: case 0x8002: case 0x8003:
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SelectPRGPage(addr & 0x03, value);
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break;
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case 0x9000: case 0x9001: case 0x9002: case 0x9003:
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case 0x9004: case 0x9005: case 0x9006: case 0x9007:
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SelectCHRPage(addr & 0x07, value);
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break;
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case 0xC002:
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_irqEnabled = false;
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CPU::ClearIRQSource(IRQSource::External);
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break;
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case 0xC003: _irqEnabled = true; break;
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case 0xC005: _irqCounter = value; break;
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case 0xD001:
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SetMirroringType(value & 0x01 ? MirroringType::Horizontal : MirroringType::Vertical);
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break;
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}
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}
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virtual void NotifyVRAMAddressChange(uint16_t addr) override
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{
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//MMC3-style A12 IRQ counter
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if(_a12Watcher.UpdateVramAddress(addr) == A12StateChange::Rise) {
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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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CPU::SetIRQSource(IRQSource::External);
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}
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}
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}
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}
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};
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