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https://github.com/libretro/Mesen.git
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94 lines
2.2 KiB
C++
94 lines
2.2 KiB
C++
#pragma once
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#include "stdafx.h"
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#include "TaitoTc0190.h"
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#include "MMC3.h"
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class TaitoTc0690 : public MMC3
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{
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private:
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uint8_t _irqDelay;
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bool _isFlintstones;
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protected:
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virtual void InitMapper() override
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{
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_irqDelay = 0;
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SelectPRGPage(2, -2);
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SelectPRGPage(3, -1);
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//This cart appears to behave differently (maybe not an identical mapper?)
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//IRQ seems to be triggered at a different timing (approx 100 cpu cycles before regular mapper 48 timings)
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_isFlintstones = _subMapperID == 255;
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}
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virtual void StreamState(bool saving) override
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{
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MMC3::StreamState(saving);
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Stream(_irqDelay);
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}
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virtual void TriggerIrq() override
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{
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//"The IRQ seems to trip a little later than it does on MMC3. It looks like about a 4 CPU cycle delay from the normal MMC3 IRQ time."
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//A value of 6 removes the shaking from The Jetsons
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_irqDelay = _isFlintstones ? 19 : 6;
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}
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void ProcessCpuClock() override
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{
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if(_irqDelay > 0) {
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_irqDelay--;
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if(_irqDelay == 0) {
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CPU::SetIRQSource(IRQSource::External);
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}
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}
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}
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virtual void WriteRegister(uint16_t addr, uint8_t value) override
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{
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switch(addr & 0xE003) {
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case 0x8000:
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SelectPRGPage(0, value & 0x3F);
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break;
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case 0x8001:
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SelectPRGPage(1, value & 0x3F);
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break;
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case 0x8002:
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SelectCHRPage(0, value * 2);
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SelectCHRPage(1, value * 2 + 1);
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break;
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case 0x8003:
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SelectCHRPage(2, value * 2);
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SelectCHRPage(3, value * 2 + 1);
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break;
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case 0xA000: case 0xA001: case 0xA002: case 0xA003:
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SelectCHRPage(4 + (addr & 0x03), value);
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break;
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case 0xC000:
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//Flintstones expects either $C000 or $C001 to clear the irq flag
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CPU::ClearIRQSource(IRQSource::External);
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_irqReloadValue = (value ^ 0xFF) + (_isFlintstones ? 0 : 1);
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break;
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case 0xC001:
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//Flintstones expects either $C000 or $C001 to clear the irq flag
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CPU::ClearIRQSource(IRQSource::External);
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_irqCounter = 0;
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_irqReload = true;
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break;
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case 0xC002:
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_irqEnabled = true;
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break;
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case 0xC003:
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_irqEnabled = false;
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CPU::ClearIRQSource(IRQSource::External);
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break;
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case 0xE000:
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SetMirroringType((value & 0x40) == 0x40 ? MirroringType::Horizontal : MirroringType::Vertical);
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break;
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}
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}
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}; |