struct MBC3 : MMIO {
bool ram_enable;
uint8 rom_select;
uint8 ram_select;
bool rtc_latch;
bool rtc_halt;
unsigned rtc_second;
unsigned rtc_minute;
unsigned rtc_hour;
unsigned rtc_day;
bool rtc_day_carry;
unsigned rtc_latch_second;
unsigned rtc_latch_minute;
unsigned rtc_latch_hour;
unsigned rtc_latch_day;
unsigned rtc_latch_day_carry;
void second();
uint8 mmio_read(uint16 addr);
void mmio_write(uint16 addr, uint8 data);
void power();
} mbc3;