i386/string/memcmp.S

/* $MidnightBSD$ */
/*
 * Copyright (c) 1993 Winning Strategies, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Winning Strategies, Inc.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <machine/asm.h>
__FBSDID("$FreeBSD: stable/10/lib/libc/i386/string/memcmp.S 217106 2011-01-07 16:08:40Z kib $");

/*
 * memcmp (void *b1, void *b2, size_t len)
 *
 * Written by:
 *      J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc.
 */

ENTRY(memcmp)
        pushl   %edi
        pushl   %esi
        movl    12(%esp),%edi
        movl    16(%esp),%esi
        cld                             /* set compare direction forward */

        movl    20(%esp),%ecx           /* compare by words */
        shrl    $2,%ecx
        repe
        cmpsl
        jne     L5                      /* do we match so far? */

        movl    20(%esp),%ecx           /* compare remainder by bytes */
        andl    $3,%ecx
        repe
        cmpsb
        jne     L6                      /* do we match? */

        xorl    %eax,%eax               /* we match, return zero        */
        popl    %esi
        popl    %edi
        ret

L5:     movl    $4,%ecx                 /* We know that one of the next */
        subl    %ecx,%edi               /* four pairs of bytes do not   */
        subl    %ecx,%esi               /* match.                       */
        repe
        cmpsb
L6:     movzbl  -1(%edi),%eax           /* Perform unsigned comparison  */
        movzbl  -1(%esi),%edx
        subl    %edx,%eax
        popl    %esi
        popl    %edi
        ret
END(memcmp)

        .section .note.GNU-stack,"",%progbits
Revision:	10585
Committed:	Fri Jun 8 12:06:55 2018 UTC (5 years, 10 months ago) by laffer1
File size:	2714 byte(s)
Log Message:	sync with freebsd
#	Content
1	/* $MidnightBSD$ */
2	/*
3	* Copyright (c) 1993 Winning Strategies, Inc.
4	* All rights reserved.
5	*
6	* Redistribution and use in source and binary forms, with or without
7	* modification, are permitted provided that the following conditions
8	* are met:
9	* 1. Redistributions of source code must retain the above copyright
10	* notice, this list of conditions and the following disclaimer.
11	* 2. Redistributions in binary form must reproduce the above copyright
12	* notice, this list of conditions and the following disclaimer in the
13	* documentation and/or other materials provided with the distribution.
14	* 3. All advertising materials mentioning features or use of this software
15	* must display the following acknowledgement:
16	* This product includes software developed by Winning Strategies, Inc.
17	* 4. The name of the author may not be used to endorse or promote products
18	* derived from this software without specific prior written permission
19	*
20	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
21	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
24	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
25	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
29	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30	*/
31
32	#include <machine/asm.h>
33	__FBSDID("$FreeBSD: stable/10/lib/libc/i386/string/memcmp.S 217106 2011-01-07 16:08:40Z kib $");
34
35	/*
36	* memcmp (void b1, void b2, size_t len)
37	*
38	* Written by:
39	* J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc.
40	*/
41
42	ENTRY(memcmp)
43	pushl %edi
44	pushl %esi
45	movl 12(%esp),%edi
46	movl 16(%esp),%esi
47	cld /* set compare direction forward */
48
49	movl 20(%esp),%ecx /* compare by words */
50	shrl $2,%ecx
51	repe
52	cmpsl
53	jne L5 /* do we match so far? */
54
55	movl 20(%esp),%ecx /* compare remainder by bytes */
56	andl $3,%ecx
57	repe
58	cmpsb
59	jne L6 /* do we match? */
60
61	xorl %eax,%eax /* we match, return zero */
62	popl %esi
63	popl %edi
64	ret
65
66	L5: movl $4,%ecx /* We know that one of the next */
67	subl %ecx,%edi /* four pairs of bytes do not */
68	subl %ecx,%esi /* match. */
69	repe
70	cmpsb
71	L6: movzbl -1(%edi),%eax /* Perform unsigned comparison */
72	movzbl -1(%esi),%edx
73	subl %edx,%eax
74	popl %esi
75	popl %edi
76	ret
77	END(memcmp)
78
79	.section .note.GNU-stack,"",%progbits