int32_t Grego::dayOfWeek(double day) {
    int32_t dow;
    ClockMath::floorDivide(day + UCAL_THURSDAY, 7, dow);
    return (dow == 0) ? UCAL_SATURDAY : dow;
}
int32_t Grego::dayOfWeek(double day) {
    int32_t dow;
    ClockMath::floorDivide(day + UCAL_THURSDAY, 7, dow);
    return (dow == 0) ? UCAL_SATURDAY : dow;
}