USPS
new.it_interval.tv_usec = reload % USPS;
new.it_interval.tv_sec = reload / USPS;
new.it_value.tv_usec = usecs % USPS;
new.it_value.tv_sec = usecs / USPS;
return ((useconds_t)(old.it_value.tv_sec * USPS + old.it_value.tv_usec));