idigitvecmultsub.s

来自「Arithmetic for integers of almost unlimi」· S 代码 · 共 41 行

#include <config.h>

/*
  Alpha assembly support for libI
  Written by Thomas Papanikolaou, June 2 1998
  internal version for John Cremona
*/

        .set noreorder
        .set noat
.text
	.align 3
	.globl DigitVecMultSub
	.ent DigitVecMultSub
DigitVecMultSub:
	.frame $30,0,$26,0
	.prologue 0
	bis $31,$31,$0		# carry = 0
	ble $19,.Lend		# if (l < 0 ) return carry
	.align 5
.Loop:
	ldq $4,0($17)		# $4 = aa = *a
	mulq $4,$18,$1		# $1 = lo = aa * m
	addq $17,8,$17		# a++
	ldq $2,0($16)		# $2 = x = *res
	subl $19,1,$19		# l--
	addq $1,$0,$1		# lo += x
	cmpult $1,$0,$3		# tmp = (low < x)
	subq $2,$1,$1		# lo = x - lo
	stq $1,0($16)		# *res = lo
	addq $16,8,$16		# res++
	cmpult $2,$1,$2		# x = (x < lo) 
	umulh $4,$18,$1		# hi = aa * m
	addq $1,$3,$0		# hi = aa * m + (low < x)
	addq $0,$2,$0		# hi = aa * m + (low < x) + (x < lo)
	bgt $19,.Loop		# if (l > 0) goto .Loop
.Lend:
	ret $31,($26),1
	.end DigitVecMultSub