C--------------------------------------------------------------------------
        subroutine ftupch(string)

C       convert input string to upper case
C
C       written by Wm Pence, HEASARC/GSFC, February 1991
C       modified 7/93 to use ichar comparisons, to improve performance

        character*(*) string
        integer i,length
        integer a,z

        a=ichar('a')
        z=ichar('z')

        length=len(string)
        do 10 i=1,length
                if   (ichar(string(i:i)) .ge. a 
     1          .and. ichar(string(i:i)) .le. z)then
                        string(i:i)=char(ichar(string(i:i))-32)
                end if
10      continue
        end