RMONCNT
RDAYCNT, RMONCNT, RYRCNT };
ret = ret ? ret : write_reg(dev, RMONCNT, bin2bcd(dt->tm_mon + 1));
tm->tm_mon = bcd2bin(readb(rtc->regbase + RMONCNT)) - 1;
writeb(bin2bcd(tm->tm_mon + 1), rtc->regbase + RMONCNT);