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https://github.com/libretro/Mesen.git
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87 lines
2.2 KiB
C++
87 lines
2.2 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 Sunsoft4 : public BaseMapper
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{
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private:
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uint8_t _ntRegs[2];
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bool _useChrForNametables;
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void UpdateNametables()
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{
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AddNametable(4, _chrRom + _ntRegs[0] * 0x400);
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AddNametable(5, _chrRom + _ntRegs[1] * 0x400);
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if(_useChrForNametables) {
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switch(GetMirroringType()) {
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case MirroringType::Vertical: SetNametables(4, 5, 4, 5); break;
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case MirroringType::Horizontal: SetNametables(4, 4, 5, 5); break;
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case MirroringType::ScreenAOnly: SetNametables(4, 4, 4, 4); break;
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case MirroringType::ScreenBOnly: SetNametables(5, 5, 5, 5); break;
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}
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} else {
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//Reset to default mirroring
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SetMirroringType(GetMirroringType());
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}
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}
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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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_useChrForNametables = false;
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_ntRegs[0] = _ntRegs[1] = 0;
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//Bank 0's initial state is undefined, but some roms expect it to be the first page
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SelectPRGPage(0, 0);
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SelectPRGPage(1, -1);
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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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Stream(_ntRegs[0], _ntRegs[1], _useChrForNametables);
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if(!saving) {
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UpdateNametables();
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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 & 0xF000) {
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case 0x8000: SelectCHRPage(0, value); break;
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case 0x9000: SelectCHRPage(1, value); break;
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case 0xA000: SelectCHRPage(2, value); break;
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case 0xB000: SelectCHRPage(3, value); break;
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case 0xC000:
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_ntRegs[0] = value | 0x80;
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UpdateNametables();
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break;
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case 0xD000:
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_ntRegs[1] = value | 0x80;
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UpdateNametables();
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break;
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case 0xE000:
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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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_useChrForNametables = (value & 0x10) == 0x10;
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UpdateNametables();
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break;
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case 0xF000:
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SelectPRGPage(0, value & 0x0F);
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//_prgRamEnabled = (value & 0x10) == 0x10;
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break;
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}
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}
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}; |