xref: /titanic_51/usr/src/lib/libc/i386/gen/memset.s (revision 9a70fc3be3b1e966bf78825cdb8d509963a6f0a1)
17c478bd9Sstevel@tonic-gate/*
27c478bd9Sstevel@tonic-gate * CDDL HEADER START
37c478bd9Sstevel@tonic-gate *
47c478bd9Sstevel@tonic-gate * The contents of this file are subject to the terms of the
58cd45542Sraf * Common Development and Distribution License (the "License").
68cd45542Sraf * You may not use this file except in compliance with the License.
77c478bd9Sstevel@tonic-gate *
87c478bd9Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
97c478bd9Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing.
107c478bd9Sstevel@tonic-gate * See the License for the specific language governing permissions
117c478bd9Sstevel@tonic-gate * and limitations under the License.
127c478bd9Sstevel@tonic-gate *
137c478bd9Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each
147c478bd9Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
157c478bd9Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the
167c478bd9Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying
177c478bd9Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner]
187c478bd9Sstevel@tonic-gate *
197c478bd9Sstevel@tonic-gate * CDDL HEADER END
207c478bd9Sstevel@tonic-gate */
218cd45542Sraf
227c478bd9Sstevel@tonic-gate/*
238cd45542Sraf * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
247c478bd9Sstevel@tonic-gate * Use is subject to license terms.
257c478bd9Sstevel@tonic-gate */
267c478bd9Sstevel@tonic-gate
27*9a70fc3bSMark J. Nelson	.file	"memset.s"
287c478bd9Sstevel@tonic-gate
297c478bd9Sstevel@tonic-gate#include <sys/asm_linkage.h>
307c478bd9Sstevel@tonic-gate
317c478bd9Sstevel@tonic-gate	ANSI_PRAGMA_WEAK(memset,function)
327c478bd9Sstevel@tonic-gate
337c478bd9Sstevel@tonic-gate#include "SYS.h"
347c478bd9Sstevel@tonic-gate
357c478bd9Sstevel@tonic-gate	ENTRY(memset)
367c478bd9Sstevel@tonic-gate	pushl	%edi		/ save register variable
377c478bd9Sstevel@tonic-gate	movl	8(%esp),%edi	/ %edi = string address
387c478bd9Sstevel@tonic-gate	movl	12(%esp),%eax	/ %al = byte to duplicate
397c478bd9Sstevel@tonic-gate	movl	16(%esp),%ecx	/ %ecx = number of copies
407c478bd9Sstevel@tonic-gate	cmpl	$20,%ecx	/ strings with 20 or more chars should
417c478bd9Sstevel@tonic-gate	jbe	.byteset	/ byteset one word at a time
427c478bd9Sstevel@tonic-gate.wordset:
437c478bd9Sstevel@tonic-gate	andl	$0xff,%eax	/ Duplicate fill const 4 times in %eax
447c478bd9Sstevel@tonic-gate	shrl	$2,%ecx		/ %ecx = number of words to set
457c478bd9Sstevel@tonic-gate	movl	%eax,%edx
467c478bd9Sstevel@tonic-gate	shll	$8,%eax		/ This is ugly, but no P6 partial stalls
477c478bd9Sstevel@tonic-gate	orl	%edx,%eax	/ get introduced as before
487c478bd9Sstevel@tonic-gate	shll	$8,%eax
497c478bd9Sstevel@tonic-gate	orl	%edx,%eax
507c478bd9Sstevel@tonic-gate	shll	$8,%eax
517c478bd9Sstevel@tonic-gate	orl	%edx,%eax
527c478bd9Sstevel@tonic-gate	rep; sstol
537c478bd9Sstevel@tonic-gate	movl	16(%esp),%ecx
547c478bd9Sstevel@tonic-gate	andl	$3,%ecx		/ %ecx = number of bytes left
557c478bd9Sstevel@tonic-gate.byteset:
567c478bd9Sstevel@tonic-gate	rep; sstob
577c478bd9Sstevel@tonic-gate	movl	8(%esp),%eax	/ return string address
587c478bd9Sstevel@tonic-gate	popl	%edi		/ restore register variable
597c478bd9Sstevel@tonic-gate	ret
607c478bd9Sstevel@tonic-gate	SET_SIZE(memset)
61