RDxR_DOW_S
tm->tm_wday = ((rycr & RDxR_DOW_MASK) >> RDxR_DOW_S) - 1;
#define RDxR_DOW_MASK (0x7 << RDxR_DOW_S)
| (((tm->tm_wday + 1) << RDxR_DOW_S) & RDxR_DOW_MASK)