struct MBC5 : Mapper {
auto read(uint16 address) -> uint8;
auto write(uint16 address, uint8 data) -> void;
auto power() -> void;
auto serialize(serializer&) -> void;
struct IO {
struct ROM {
uint9 bank = 0x01;
} rom;
struct RAM {
uint1 enable;
uint4 bank;
} ram;
} io;
} mbc5;