!      call  j1980(m,d,yr,days)
!      returns days since + including  1 jan 1980    (jan1 1980 = 1) 
!      up to given date (not necessarily today)
    subroutine j1980(m,d,yr,days)
    implicit none
    integer, intent(in)::  m,d,yr
    integer, intent(out):: days
    integer jof
    days=365*(yr-1980)+(yr-1980+3)/4 !day +years +leaps till 2100
    days=days-(yr-1901)/100	     !subtract century (non leap)
    days=days+(yr-1601)/400	     !restore quadcentury (are leap)
    call jdold(m,d,yr,jof)           !day of old year
    days=days+jof
    return
    end subroutine j1980