; Return in registers RDX:RAX the absolute value (module) of the difference
; between the signed double words in registers RCX:RDX and RSI:RDI.

option prologue:none, epilogue:none
.code
absd128	proc
_absd128 proc
	SUB	RDX,RDI	; Subtract the low
	SBB	RCX,RSI	; and the high words
	.if (less?)
		NEG	RDX	; O = 0, S = 1 or O = 1, S = 0: module < 0
		ADC	RCX,0	; - negate
		NEG	RCX
	.endif
	XCHG	RAX,RDX
	MOV	RDX,RCX	; Return the absolute value in RDX:RAX
	RET
; Canonical solution:
;	CMP	RCX,RSI	; Compare the high words
;	.if (less? || equal? && RDX < RDI)
;		XCHG	RCX,RSI ; Minuend < subtrahend: exchange the high
;		XCHG	RDX,RDI	; and the low words of the numbers
;	.endif
;	SUB	RDX,RDI	; Subtract the low
;	SBB	RCX,RSI	; and the high words
;	XCHG	RAX,RDX
;	MOV	RDX,RCX	; Return the absolute value in RDX:RAX
;	RET
_absd128 endp
absd128	endp
end