idigitmult.s

来自「Arithmetic for integers of almost unlimi」· S 代码 · 共 32 行

; Thomas Pfahler, Nov 21 1997
; DigitType  DigitMult (prod, a,   b  )
;                       $26,  $25, $24
;      DigitType *prod, a, b;
;{
;      *prod=LOW(a*b);
;      return HIGH(a*b);
;} 

	.CODE
	.EXPORT DigitMult
DigitMult
	.PROC
	.CALLINFO FRAME=0,NO_CALLS
	.ENTRY
					
	stw 		%r25,-16(0,%r30)
	fldws 		-16(0,%r30),%fr9L	; a -> %fr9L
	stw 		%r24,-16(0,%r30)
	fldws 		-16(0,%r30),%fr9R	; b -> %fr9R
	xmpyu 		%fr9L,%fr9R,%fr8	; a*b -> %fr8
	fstws 		%fr8R,-16(0,%r30)
	ldw 		-16(0,%r30),%r28	; lo(prod) -> %r28
	stw 		%r28,0(0,%r26)		; store lo(prod)
	
	fstws 		%fr8L,-16(0,%r30)
	bv		0(%r2)
	 ldw 		-16(0,%r30),%r28	; hi(prod) -> %r28
	
	.EXIT
	.PROCEND