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

44 lines
1.1 KiB
C++

auto Cartridge::MBC1M::read(uint16 address) -> uint8 {
if((address & 0xc000) == 0x0000) { //$0000-3fff
if(io.mode == 0) return cartridge.rom.read(address.bits(0,13));
return cartridge.rom.read(io.rom.bank.bits(4,5) << 18 | address.bits(0,13));
}
if((address & 0xc000) == 0x4000) { //$4000-7fff
return cartridge.rom.read(io.rom.bank << 14 | address.bits(0,13));
}
if((address & 0xe000) == 0xa000) { //$a000-bfff
return cartridge.ram.read(address.bits(0,12));
}
return 0xff;
}
auto Cartridge::MBC1M::write(uint16 address, uint8 data) -> void {
if((address & 0xe000) == 0x2000) { //$2000-3fff
io.rom.bank.bits(0,3) = data.bits(0,3);
}
if((address & 0xe000) == 0x4000) { //$4000-5fff
io.rom.bank.bits(4,5) = data.bits(0,1);
}
if((address & 0xe000) == 0x6000) { //$6000-7fff
io.mode = data.bit(0);
}
if((address & 0xe000) == 0xa000) { //$a000-bfff
cartridge.ram.write(address.bits(0,13), data);
}
}
auto Cartridge::MBC1M::power() -> void {
io = {};
}
auto Cartridge::MBC1M::serialize(serializer& s) -> void {
s.integer(io.mode);
s.integer(io.rom.bank);
}