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https://github.com/SourMesen/Mesen.git
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122 lines
3.3 KiB
C++
122 lines
3.3 KiB
C++
#pragma once
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#include "BaseMapper.h"
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#include "CPU.h"
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class BandaiFcg : public BaseMapper
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{
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private:
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bool _irqEnabled;
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uint16_t _irqCounter;
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uint16_t _irqReload;
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uint8_t _prgPage;
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uint8_t _prgBankSelect;
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uint8_t _chrRegs[8];
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protected:
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uint16_t GetPRGPageSize() override { return 0x4000; }
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uint16_t GetCHRPageSize() override { return 0x400; }
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uint16_t RegisterStartAddress() override { return 0x6000; }
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uint16_t RegisterEndAddress() override { return 0xFFFF; }
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bool AllowRegisterRead() override { return true; }
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void InitMapper() override
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{
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memset(_chrRegs, 0, sizeof(_chrRegs));
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_irqEnabled = false;
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_irqCounter = 0;
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_irqReload = 0;
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_prgPage = 0;
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_prgBankSelect = 0;
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//Only allow reads from 0x6000 to 0xFFFF
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RemoveRegisterRange(0x8000, 0xFFFF, MemoryOperation::Read);
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if(_mapperID != 16 || GetPRGPageCount() >= 0x20) {
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//"For iNES Mapper 153 (with SRAM), the writeable ports must only be mirrored across $8000-$FFFF."
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//"Mappers 157 and 159 do not need to support the FCG-1 and -2 and so should only mirror the ports across $8000-$FFFF."
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RemoveRegisterRange(0x6000, 0x7FFF, MemoryOperation::Any);
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}
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//Last bank
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SelectPRGPage(1, 0x0F);
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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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ArrayInfo<uint8_t> chrRegs{ _chrRegs, 8 };
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Stream(_irqEnabled, _irqCounter, _irqReload, _prgPage, _prgBankSelect, chrRegs);
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}
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void ProcessCpuClock() override
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{
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if(_irqEnabled) {
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//Checking counter before decrementing seems to be the only way to get both
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//Famicom Jump II - Saikyou no 7 Nin (J) and Magical Taruruuto-kun 2 - Mahou Daibouken (J)
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//to work without glitches with the same code.
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if(_irqCounter == 0) {
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CPU::SetIRQSource(IRQSource::External);
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}
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_irqCounter--;
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}
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}
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uint8_t ReadRegister(uint16_t addr) override
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{
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//Pretend EEPROM data is always 0
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return 0;
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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 & 0x000F) {
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case 0x00: case 0x01: case 0x02: case 0x03: case 0x04: case 0x05: case 0x06: case 0x07:
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_chrRegs[addr & 0x07] = value;
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if(_mapperID == 153 || GetPRGPageCount() >= 0x20) {
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_prgBankSelect = 0;
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for(int i = 0; i < 8; i++) {
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_prgBankSelect |= (_chrRegs[i] & 0x01) << 4;
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}
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SelectPRGPage(0, _prgPage | _prgBankSelect);
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SelectPRGPage(1, 0x0F | _prgBankSelect);
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} else if(!HasChrRam() && _mapperID != 157) {
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SelectCHRPage(addr & 0x07, value);
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}
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break;
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case 0x08:
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_prgPage = value & 0x0F;
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SelectPRGPage(0, _prgPage | _prgBankSelect);
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break;
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case 0x09:
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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 0x0A:
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//Wiki claims there is no reload value, however this seems to be the only way to make Famicom Jump II - Saikyou no 7 Nin work properly
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_irqEnabled = (value & 0x01) == 0x01;
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_irqCounter = _irqReload;
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CPU::ClearIRQSource(IRQSource::External);
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break;
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case 0x0B:
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_irqReload = (_irqReload & 0xFF00) | value;
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break;
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case 0x0C:
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_irqReload = (_irqReload & 0xFF) | (value << 8);
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break;
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case 0x0D:
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//TODO: PRG RAM Enable / EEPROM Control
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break;
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}
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}
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}; |