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

41 lines
955 B
C++

auto Cartridge::MBC1M::readIO(uint16 addr) -> uint8 {
if((addr & 0xc000) == 0x0000) { //$0000-3fff
if(mode == 0) return cartridge.readROM((uint14)addr);
return cartridge.readROM(rom.hi << 18 | (uint14)addr);
}
if((addr & 0xc000) == 0x4000) { //$4000-7fff
return cartridge.readROM(rom.hi << 18 | rom.lo << 14 | (uint14)addr);
}
if((addr & 0xe000) == 0xa000) { //$a000-bfff
return cartridge.readRAM((uint13)addr);
}
return 0xff;
}
auto Cartridge::MBC1M::writeIO(uint16 addr, uint8 data) -> void {
if((addr & 0xe000) == 0x2000) { //$2000-3fff
rom.lo = data.bits(0,3);
}
if((addr & 0xe000) == 0x4000) { //$4000-5fff
rom.hi = data.bits(0,1);
}
if((addr & 0xe000) == 0x6000) { //$6000-7fff
mode = data.bit(0);
}
if((addr & 0xe000) == 0xa000) { //$a000-bfff
cartridge.writeRAM((uint13)addr, data);
}
}
auto Cartridge::MBC1M::power() -> void {
rom.lo = 1;
rom.hi = 0;
mode = 0;
}