idigitvecmultadd.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 DigitVecMultAdd
	.ent DigitVecMultAdd
DigitVecMultAdd:
	.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,$2		# $2 = lo = low_digit(a * m)
	addq $17,8,$17		# a++
	ldq $1,0($16)		# $1 = x = *res
	subl $19,1,$19		# l--;
	addq $2,$0,$2		# lo += carry
	cmpult $2,$0,$3		# tmp = (lo < carry)
	addq $2,$1,$2		# lo += x;
	stq $2,0($16)		# *res = x
	addq $16,8,$16		# res++
	cmpult $2,$1,$2		# lo = (lo < x);
	umulh $4,$18,$1		# x = high_digit(a * m)
	addq $1,$3,$0		# carry = x + (lo < carry)
	addq $0,$2,$0		# carry = x + (lo < carry) + (lo < x) 
	bgt $19,.Loop		# if (l > 0) goto .Loop
.Lend:
	ret $31,($26),1
	.end DigitVecMultAdd