C+
C NAME:
C	Bit4to2
C PURPOSE:
C       Copy the two least signficant bytes of an integer*4 into
C       an integer*2 variable.
C CALLING SEQUENCE:
	subroutine Bit4to2(I4,I2)
C INPUTS:
C	I4	integer*4	any integer*4
C OUTPUTS:
C	I2	integer*2	result in range [-32768,32767]
C CALLS:
C	(none)
C PROCEDURE:
C	iand(I4,Z'7FFF')        copies the least significant 15 bits
C	iand(I4,Z'FFFF')/Z'8000'=0/1 is the 16 bit
C	iand(I4,Z'FFFF')/Z'8000')*Z'8000' sets the sign bit of the integer*2
C MODIFICATION HISTORY:
C	SEP-1998, Paul Hick (UCSD/CASS; pphick@ucsd.edu)
C-
	    integer*4 I4
	    integer*2 I2

	I2 = iand(I4,Z'7FFF')-iand(I4,Z'FFFF')/Z'8000'*Z'8000'

	return
	end