bsnes/higan/gb/cartridge/mbc6/mbc6.cpp

75 lines
1.8 KiB
C++

auto Cartridge::MBC6::read(uint16 address) -> uint8 {
if((address & 0xc000) == 0x0000) { //$0000-3fff
return cartridge.rom.read(address.bits(0,13));
}
if((address & 0xe000) == 0x4000) { //$4000-5fff
return cartridge.rom.read(io.rom.bank[0] << 13 | address.bits(0,12));
}
if((address & 0xe000) == 0x6000) { //$6000-7fff
return cartridge.rom.read(io.rom.bank[1] << 13 | address.bits(0,12));
}
if((address & 0xf000) == 0xa000) { //$a000-afff
if(!io.ram.enable) return 0xff;
return cartridge.ram.read(io.ram.bank[0] << 12 | address.bits(0,11));
}
if((address & 0xf000) == 0xb000) { //$b000-bfff
if(!io.ram.enable) return 0xff;
return cartridge.ram.read(io.ram.bank[1] << 12 | address.bits(0,11));
}
return 0xff;
}
auto Cartridge::MBC6::write(uint16 address, uint8 data) -> void {
if((address & 0xfc00) == 0x0000) {
io.ram.enable = data.bits(0,3) == 0xa;
return;
}
if((address & 0xfc00) == 0x0400) {
io.ram.bank[0] = data;
return;
}
if((address & 0xfc00) == 0x0800) {
io.ram.bank[1] = data;
return;
}
if((address & 0xf800) == 0x2000) {
io.rom.bank[0] = data;
return;
}
if((address & 0xf800) == 0x3000) {
io.rom.bank[1] = data;
return;
}
if((address & 0xf000) == 0xa000) { //$a000-afff
if(!io.ram.enable) return;
return cartridge.ram.write(io.ram.bank[0] << 12 | address.bits(0,11), data);
}
if((address & 0xf000) == 0xb000) { //$b000-bfff
if(!io.ram.enable) return;
return cartridge.ram.write(io.ram.bank[1] << 12 | address.bits(0,11), data);
}
}
auto Cartridge::MBC6::power() -> void {
io = {};
}
auto Cartridge::MBC6::serialize(serializer& s) -> void {
s.integer(io.rom.bank[0]);
s.integer(io.rom.bank[1]);
s.integer(io.ram.enable);
s.integer(io.ram.bank[0]);
s.integer(io.ram.bank[1]);
}