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55 lines
1.3 KiB
C++
55 lines
1.3 KiB
C++
#pragma once
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#include "stdafx.h"
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#include "MMC3.h"
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//iNES Mapper 224 is used for the <20>»‰È‘× (Jncota) KT-008 PCB. It's an MMC3 clone that supports 1024 KiB of PRG-ROM
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//through an additional outer bank register at $5000.
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//http://wiki.nesdev.com/w/index.php/INES_Mapper_224
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class MMC3_224 : public MMC3
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{
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private:
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uint8_t _outerBank;
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protected:
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void InitMapper() override
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{
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_outerBank = 0;
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AddRegisterRange(0x5000, 0x5003, MemoryOperation::Write);
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MMC3::InitMapper();
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}
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void StreamState(bool saving) override
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{
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MMC3::StreamState(saving);
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Stream(_outerBank);
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}
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void UpdatePrgMapping() override
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{
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uint8_t outerBank = _outerBank << 6;
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if(_prgMode == 0) {
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SelectPRGPage(0, (_registers[6] & 0x3F) | outerBank);
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SelectPRGPage(1, (_registers[7] & 0x3F) | outerBank);
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SelectPRGPage(2, 0x3E | outerBank);
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SelectPRGPage(3, 0x3F | outerBank);
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} else if(_prgMode == 1) {
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SelectPRGPage(0, 0x3E | outerBank);
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SelectPRGPage(1, (_registers[6] & 0x3F) | outerBank);
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SelectPRGPage(2, (_registers[7] & 0x3F) | outerBank);
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SelectPRGPage(3, 0x3F | outerBank);
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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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if(addr < 0x8000) {
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if(addr == 0x5000) {
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_outerBank = (value >> 2) & 0x01;
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UpdatePrgMapping();
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}
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} else {
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MMC3::WriteRegister(addr, value);
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}
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}
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}; |