RCR1_AIE
tmp &= ~(RCR1_AF | RCR1_AIE);
tmp |= RCR1_AIE;
tmp &= ~RCR1_AIE;
wkalrm->enabled = (readb(rtc->regbase + RCR1) & RCR1_AIE) ? 1 : 0;
rcr1 &= ~(RCR1_AF | RCR1_AIE);
rcr1 |= RCR1_AIE;
tmp &= ~(RCR1_CIE | RCR1_AIE);