.title	sub_quadtime
;
;	call sequence
;
;	call sub_quadtime(a, b, c)
;
;	where a, b, and c are quadword system time buffers
;
;	c = a - b
;
a = 4
b = 8
c = 12
sub_quadtime::	.word	^m<r2>
		movq	@a(ap),r0	; minuend in registers
		movl	b(ap),r2	; address of subtrahend in r2
		subl	(r2),r0		; subtract low order half
		sbwc	4(r2),r1	; subtract high@order half with carry
;
;	we now have the time increment between a and b.  The system
;	form of a delta time is the negative of this.  We get this by
;	subtracting from 0.
;
		movl	c(ap),r2	; address of destination in r2
		clrl	(r2)		; set to 0
		clrl	4(r2)
		subl	r0,(r2)		; subtract low half
		sbwc	r1,4(r2)	; subtract high half
		ret
		.end