HelenOS sources
floor_mod 280 uspace/lib/c/generic/time.c return floor_mod(days_since_epoch(year, mon, mday) + 4, 7);
floor_mod 308 uspace/lib/c/generic/time.c nsec = floor_mod(nsec, NSECS_PER_SEC);
floor_mod 310 uspace/lib/c/generic/time.c sec = floor_mod(sec, SECS_PER_MIN);
floor_mod 312 uspace/lib/c/generic/time.c min = floor_mod(min, MINS_PER_HOUR);
floor_mod 314 uspace/lib/c/generic/time.c hour = floor_mod(hour, HOURS_PER_DAY);
floor_mod 318 uspace/lib/c/generic/time.c mon = floor_mod(mon, 12);
floor_mod 324 uspace/lib/c/generic/time.c day = floor_mod(day, 146097);
floor_mod 398 uspace/lib/c/generic/time.c return floor_mod(4 - start_wday, 7) - 3;
HelenOS homepage, sources at GitHub