Algorithm

Development Platform:

Unix_Linux

rshift.asm：Code Content

							dnl  MIPS32 mpn_rshift -- Right shift.
dnl  Copyright 1995, 2000, 2002 Free Software Foundation, Inc.
dnl  This file is part of the GNU MP Library.
dnl  The GNU MP Library is free software; you can redistribute it and/or modify
dnl  it under the terms of the GNU Lesser General Public License as published
dnl  by the Free Software Foundation; either version 3 of the License, or (at
dnl  your option) any later version.
dnl  The GNU MP Library is distributed in the hope that it will be useful, but
dnl  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
dnl  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
dnl  License for more details.
dnl  You should have received a copy of the GNU Lesser General Public License
dnl  along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.
include(`../config.m4')
C INPUT PARAMETERS
C res_ptr	$4
C src_ptr	$5
C size		$6
C cnt		$7
ASM_START()
PROLOGUE(mpn_rshift)
	lw	$10,0($5)	C load first limb
	subu	$13,$0,$7
	addiu	$6,$6,-1
	and	$9,$6,4-1	C number of limbs in first loop
	beq	$9,$0,.L0	C if multiple of 4 limbs, skip first loop
	 sll	$2,$10,$13	C compute function result
	subu	$6,$6,$9
.Loop0:	lw	$3,4($5)
	addiu	$4,$4,4
	addiu	$5,$5,4
	addiu	$9,$9,-1
	srl	$11,$10,$7
	sll	$12,$3,$13
	move	$10,$3
	or	$8,$11,$12
	bne	$9,$0,.Loop0
	 sw	$8,-4($4)
.L0:	beq	$6,$0,.Lend
	 nop
.Loop:	lw	$3,4($5)
	addiu	$4,$4,16
	addiu	$6,$6,-4
	srl	$11,$10,$7
	sll	$12,$3,$13
	lw	$10,8($5)
	srl	$14,$3,$7
	or	$8,$11,$12
	sw	$8,-16($4)
	sll	$9,$10,$13
	lw	$3,12($5)
	srl	$11,$10,$7
	or	$8,$14,$9
	sw	$8,-12($4)
	sll	$12,$3,$13
	lw	$10,16($5)
	srl	$14,$3,$7
	or	$8,$11,$12
	sw	$8,-8($4)
	sll	$9,$10,$13
	addiu	$5,$5,16
	or	$8,$14,$9
	bgtz	$6,.Loop
	 sw	$8,-4($4)
.Lend:	srl	$8,$10,$7
	j	$31
	sw	$8,0($4)
EPILOGUE(mpn_rshift)

						