struct MBC5 : MMIO {
bool ram_enable; //$0000-1fff
uint16 rom_select; //$2000-2fff + $3000-3fff
uint8 ram_select; //$4000-5fff
uint8 mmio_read(uint16 addr);
void mmio_write(uint16 addr, uint8 data);
void power();
} mbc5;