mirror of
https://github.com/SourMesen/Mesen.git
synced 2024-05-20 05:01:03 -04:00
71 lines
1.7 KiB
C++
71 lines
1.7 KiB
C++
#pragma once
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#include "MMC3.h"
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class MMC3_219 : public MMC3
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{
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private:
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uint8_t _exRegs[3];
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protected:
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void InitMapper() override
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{
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MMC3::InitMapper();
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SelectPrgPage4x(0, -4);
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SelectChrPage8x(0, 0);
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_exRegs[0] = _exRegs[1] = _exRegs[2] = 0;
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}
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void UpdatePrgMapping() override
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{
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}
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void UpdateChrMapping() override
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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 < 0xA000) {
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switch(addr & 0xE003) {
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case 0x8000:
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_exRegs[0] = 0;
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_exRegs[1] = value;
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break;
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case 0x8001:
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if(_exRegs[0] >= 0x23 && _exRegs[0] <= 0x26) {
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uint8_t prgBank = ((value & 0x20) >> 5) | ((value & 0x10) >> 3) | ((value & 0x08) >> 1) | ((value & 0x04) << 1);
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SelectPRGPage(0x26 - _exRegs[0], prgBank);
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}
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switch(_exRegs[1]) {
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case 0x08: case 0x0A: case 0x0E: case 0x12: case 0x16: case 0x1A: case 0x1E:
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_exRegs[2] = value << 4;
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break;
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case 0x09: SelectCHRPage(0, _exRegs[2] | (value >> 1 & 0x0E)); break;
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case 0x0B: SelectCHRPage(1, _exRegs[2] | (value >> 1 | 0x1)); break;
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case 0x0C:
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case 0x0D: SelectCHRPage(2, _exRegs[2] | (value >> 1 & 0xE)); break;
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case 0x0F: SelectCHRPage(3, _exRegs[2] | (value >> 1 | 0x1)); break;
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case 0x10:
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case 0x11: SelectCHRPage(4, _exRegs[2] | (value >> 1 & 0xF)); break;
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case 0x14:
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case 0x15: SelectCHRPage(5, _exRegs[2] | (value >> 1 & 0xF)); break;
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case 0x18:
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case 0x19: SelectCHRPage(6, _exRegs[2] | (value >> 1 & 0xF)); break;
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case 0x1C:
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case 0x1D: SelectCHRPage(7, _exRegs[2] | (value >> 1 & 0xF)); break;
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}
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break;
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case 0x8002:
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_exRegs[0] = value;
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_exRegs[1] = 0;
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break;
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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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}; |