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68 lines
1.7 KiB
C++
68 lines
1.7 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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class Sunsoft3 : public BaseMapper
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{
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private:
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bool _irqLatch = false;
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bool _irqEnabled = false;
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uint16_t _irqCounter = 0;
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protected:
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virtual uint16_t GetPRGPageSize() override { return 0x4000; }
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virtual uint16_t GetCHRPageSize() override { return 0x800; }
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void InitMapper() override
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{
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SelectPRGPage(1, -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(_irqLatch, _irqEnabled, _irqCounter);
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}
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virtual void ProcessCpuClock() override
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{
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if(_irqEnabled) {
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_irqCounter--;
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if(_irqCounter == 0xFFFF) {
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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 WriteRegister(uint16_t addr, uint8_t value) override
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{
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switch(addr & 0xF800) {
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case 0x8800: SelectCHRPage(0, value); break;
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case 0x9800: SelectCHRPage(1, value); break;
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case 0xA800: SelectCHRPage(2, value); break;
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case 0xB800: SelectCHRPage(3, value); break;
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case 0xC800:
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_irqCounter &= _irqLatch ? 0xFF00 : 0x00FF;
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_irqCounter |= _irqLatch ? value : (value << 8);
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_irqLatch = !_irqLatch;
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break;
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case 0xD800:
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_irqEnabled = (value & 0x10) == 0x10;
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_irqLatch = false;
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_console->GetCpu()->ClearIrqSource(IRQSource::External);
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break;
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case 0xE800:
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switch(value & 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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break;
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case 0xF800: SelectPRGPage(0, value); break;
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}
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}
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};
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