bsnes/higan/gb/cartridge/mbc1m/mbc1m.cpp

41 lines
996 B
C++

auto Cartridge::MBC1M::mmio_read(uint16 addr) -> uint8 {
if((addr & 0xc000) == 0x0000) { //$0000-3fff
if(!modeSelect) return cartridge.rom_read(addr & 0x3fff);
return cartridge.rom_read((romHi << 4) * 0x4000 + (addr & 0x3fff));
}
if((addr & 0xc000) == 0x4000) { //$4000-7fff
return cartridge.rom_read((romHi << 4 | romLo) * 0x4000 + (addr & 0x3fff));
}
if((addr & 0xe000) == 0xa000) { //$a000-bfff
return cartridge.ram_read(addr & 0x1fff);
}
return 0xff;
}
auto Cartridge::MBC1M::mmio_write(uint16 addr, uint8 data) -> void {
if((addr & 0xe000) == 0x2000) { //$2000-3fff
romLo = data.bits(0,3);
}
if((addr & 0xe000) == 0x4000) { //$4000-5fff
romHi = data.bits(0,1);
}
if((addr & 0xe000) == 0x6000) { //$6000-7fff
modeSelect = data.bit(0);
}
if((addr & 0xe000) == 0xa000) { //$a000-bfff
cartridge.ram_write(addr & 0x1fff, data);
}
}
auto Cartridge::MBC1M::power() -> void {
romHi = 0;
romLo = 1;
modeSelect = 0;
}