the program /xray2/berry/for/raxhead2.for has a swapbytes routine
for reals going either way.
should work also on integer*4? if fortran will ignore type
mismatch and just pass the bytes. except factor of 4 inappropriate then.

	subroutine byteswapr4(value)
	real*4 value,exch1,exch2
	character*1 exbyt1(4),exbyt2(4)
	equivalence (exch1,exbyt1(1))
	equivalence (exch2,exbyt2(1))

	exch1=value
        exbyt2(1)=exbyt1(2)
	exbyt2(2)=exbyt1(1)
	exbyt2(3)=exbyt1(4)
	exbyt2(4)=exbyt1(3)
c	value= exch2*4.0		!if run on vms-type machine (but file access needs fixing)
	value= exch2/4.0		!if run on unix machine
	return
	end

c-----------------------------------------
	subroutine byteswapi4(value)
	integer*4 value,exch1,exch2
	character*1 exbyt1(4),exbyt2(4)
	equivalence (exch1,exbyt1(1))
	equivalence (exch2,exbyt2(1))

	exch1=value
        exbyt2(1)=exbyt1(2)
	exbyt2(2)=exbyt1(1)
	exbyt2(3)=exbyt1(4)
	exbyt2(4)=exbyt1(3)
	value= exch2
	return
	end



c-----------------------------------------
	subroutine byteswapi2(value)
	real*4 value,exch1,exch2
	character*1 exbyt1(2),exbyt2(2)
	equivalence (exch1,exbyt1(1))
	equivalence (exch2,exbyt2(1))

	exch1=value
        exbyt2(1)=exbyt1(2)
	exbyt2(2)=exbyt1(1)
	value= exch2
	return
	end