bsnes/higan/gb/cartridge/mbc5/mbc5.cpp

50 lines
1.1 KiB
C++
Raw Normal View History

auto Cartridge::MBC5::readIO(uint16 addr) -> uint8 {
if((addr & 0xc000) == 0x0000) { //$0000-3fff
return cartridge.readROM(addr);
}
if((addr & 0xc000) == 0x4000) { //$4000-7fff
return cartridge.readROM(rom.select << 14 | (uint14)addr);
}
if((addr & 0xe000) == 0xa000) { //$a000-bfff
if(ram.enable) return cartridge.readRAM(ram.select << 13 | (uint13)addr);
return 0xff;
}
return 0xff;
}
auto Cartridge::MBC5::writeIO(uint16 addr, uint8 data) -> void {
if((addr & 0xe000) == 0x0000) { //$0000-1fff
ram.enable = data.bits(0,3) == 0x0a;
return;
}
if((addr & 0xf000) == 0x2000) { //$2000-2fff
rom.select.byte(0) = data;
return;
}
if((addr & 0xf000) == 0x3000) { //$3000-3fff
rom.select.byte(1) = data.bit(0);
return;
}
if((addr & 0xe000) == 0x4000) { //$4000-5fff
ram.select = data.bits(0,3);
return;
}
if((addr & 0xe000) == 0xa000) { //$a000-bfff
if(ram.enable) cartridge.writeRAM(ram.select << 13 | (uint13)addr, data);
return;
}
}
auto Cartridge::MBC5::power() -> void {
rom.select = 0x001;
ram.enable = false;
ram.select = 0x00;
}