mirror of
https://github.com/SourMesen/Mesen2.git
synced 2025-04-02 10:21:44 -04:00
65 lines
No EOL
1.6 KiB
C++
65 lines
No EOL
1.6 KiB
C++
#pragma once
|
|
#include "pch.h"
|
|
#include "NES/BaseMapper.h"
|
|
|
|
class VRC1 : public BaseMapper
|
|
{
|
|
private:
|
|
uint8_t _chrBanks[2] = {};
|
|
|
|
void UpdateChrBanks()
|
|
{
|
|
SelectChrPage(0, _chrBanks[0]);
|
|
SelectChrPage(1, _chrBanks[1]);
|
|
}
|
|
|
|
protected:
|
|
uint16_t GetPrgPageSize() override { return 0x2000; }
|
|
uint16_t GetChrPageSize() override { return 0x1000; }
|
|
|
|
void InitMapper() override
|
|
{
|
|
SelectPrgPage(3, -1);
|
|
}
|
|
|
|
void Serialize(Serializer& s) override
|
|
{
|
|
BaseMapper::Serialize(s);
|
|
SV(_chrBanks[0]);
|
|
SV(_chrBanks[1]);
|
|
}
|
|
|
|
void WriteRegister(uint16_t addr, uint8_t value) override
|
|
{
|
|
//TODO: Create a setting to enable/disable oversized PRG
|
|
bool allowOversizedPrg = true;
|
|
uint8_t prgMask = allowOversizedPrg ? 0xFF : 0x0F;
|
|
|
|
switch(addr & 0xF000) {
|
|
case 0x8000: SelectPrgPage(0, value & prgMask); break;
|
|
|
|
case 0x9000:
|
|
if(GetMirroringType() != MirroringType::FourScreens) {
|
|
//"The mirroring bit is ignored if the cartridge is wired for 4-screen VRAM, as is typical for Vs. System games using the VRC1."
|
|
SetMirroringType((value & 0x01) == 0x01 ? MirroringType::Horizontal : MirroringType::Vertical);
|
|
}
|
|
_chrBanks[0] = (_chrBanks[0] & 0x0F) | ((value & 0x02) << 3);
|
|
_chrBanks[1] = (_chrBanks[1] & 0x0F) | ((value & 0x04) << 2);
|
|
UpdateChrBanks();
|
|
break;
|
|
|
|
case 0xA000: SelectPrgPage(1, value & prgMask); break;
|
|
case 0xC000: SelectPrgPage(2, value & prgMask); break;
|
|
|
|
case 0xE000:
|
|
_chrBanks[0] = (_chrBanks[0] & 0x10) | (value & 0x0F);
|
|
UpdateChrBanks();
|
|
break;
|
|
|
|
case 0xF000:
|
|
_chrBanks[1] = (_chrBanks[1] & 0x10) | (value & 0x0F);
|
|
UpdateChrBanks();
|
|
break;
|
|
}
|
|
}
|
|
}; |