EXTERNAL

SUB caldat (julian, mm, id, iyyy)

    FUNCTION fint(x)        ! The Fortran INT function
        LET fint = truncate(x,0)
    END FUNCTION

    LET igreg = 2299161

    IF julian >= igreg then
       LET jalpha = fint(((julian - 1867216) - .25) / 36524.25)
       LET ja = julian + 1 + jalpha - fint(.25 * jalpha)
    ELSE
       LET ja = julian
    END IF
    LET jb = ja + 1524
    LET jc = fint(6680 + ((jb - 2439870) - 122.1) / 365.25)
    LET jd = 365 * jc + fint(.25 * jc)
    LET je = fint((jb - jd) / 30.6001)
    LET id = jb - jd - fint(30.6001 * je)
    LET mm = je - 1
    IF mm > 12 then LET mm = mm - 12
    LET iyyy = jc - 4715
    IF mm > 2 then LET iyyy = iyyy - 1
    IF iyyy <= 0 then LET iyyy = iyyy - 1

END SUB