fixed_from_julian
rd = fixed_from_julian(&date);
int paschal_moon = fixed_from_julian(&april19) - shifted_epact;
if (rd < fixed_from_julian(&d))
pdays = rd - fixed_from_julian(&d);
date->day = rd - fixed_from_julian(&d) + 1;
rd = fixed_from_julian(&date);
rd_begin = fixed_from_julian(&date);
rd_end = fixed_from_julian(&date);
rd = fixed_from_julian(&date);
rd_begin = fixed_from_julian(&date);
rd_end = fixed_from_julian(&date);
int fixed_from_julian(const struct date *date);