glibc/sysdeps/mips/mips64/rshift.S

/* MIPS3 __mpn_rshift --
 *
 * Copyright (C) 1995-2017 Free Software Foundation, Inc.
 *
 * This file is part of the GNU MP Library.
 *
 * The GNU MP Library is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or (at your
 * option) any later version.
 *
 * The GNU MP Library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with the GNU MP Library.  If not, see
 * <http://www.gnu.org/licenses/>.
 */

#include <sysdep.h>
#include <sys/asm.h>

/* INPUT PARAMETERS
 * res_ptr	$4
 * src_ptr	$5
 * size		$6
 * cnt		$7
 */

#ifdef __PIC__
	.option pic2
#endif
ENTRY (__mpn_rshift)
#ifdef __PIC__
	SETUP_GP /* ??? unused */
#endif
	.set	noreorder
	.set	nomacro

	ld	$10,0($5)	# load first limb
	dsubu	$13,$0,$7
	daddiu	$6,$6,-1
	and	$9,$6,4-1	# number of limbs in first loop
	beq	$9,$0,L(L0)	# if multiple of 4 limbs, skip first loop
	dsll	$2,$10,$13	# compute function result

	dsubu	$6,$6,$9

L(Loop0):	ld	$3,8($5)
	daddiu	$4,$4,8
	daddiu	$5,$5,8
	daddiu	$9,$9,-1
	dsrl	$11,$10,$7
	dsll	$12,$3,$13
	move	$10,$3
	or	$8,$11,$12
	bne	$9,$0,L(Loop0)
	sd	$8,-8($4)

L(L0):	beq	$6,$0,L(Lend)
	nop

L(Loop):	ld	$3,8($5)
	daddiu	$4,$4,32
	daddiu	$6,$6,-4
	dsrl	$11,$10,$7
	dsll	$12,$3,$13

	ld	$10,16($5)
	dsrl	$14,$3,$7
	or	$8,$11,$12
	sd	$8,-32($4)
	dsll	$9,$10,$13

	ld	$3,24($5)
	dsrl	$11,$10,$7
	or	$8,$14,$9
	sd	$8,-24($4)
	dsll	$12,$3,$13

	ld	$10,32($5)
	dsrl	$14,$3,$7
	or	$8,$11,$12
	sd	$8,-16($4)
	dsll	$9,$10,$13

	daddiu	$5,$5,32
	or	$8,$14,$9
	bgtz	$6,L(Loop)
	sd	$8,-8($4)

L(Lend):	dsrl	$8,$10,$7
	j	$31
	sd	$8,0($4)
END (__mpn_rshift)