RTC_RTCISR
writew(readw(ioaddr + RTC_RTCISR), ioaddr + RTC_RTCISR);
status = readw(ioaddr + RTC_RTCISR) & readw(ioaddr + RTC_RTCIENR);
writew(status, ioaddr + RTC_RTCISR);
alrm->pending = ((readw(ioaddr + RTC_RTCISR) & RTC_ALM_BIT)) ? 1 : 0;