strcmp.S revision 81586 
1/*
2 * Copyright (c) 1993 Winning Strategies, Inc.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *      This product includes software developed by Winning Strategies, Inc.
16 * 4. The name of the author may not be used to endorse or promote products
17 *    derived from this software withough specific prior written permission
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#if defined(LIBC_RCS) && !defined(lint)
32	.text
33        .asciz "$FreeBSD: head/lib/libc/i386/string/strcmp.S 81586 2001-08-13 14:06:34Z ru $"
34#endif /* LIBC_RCS and not lint */
35
36#include "DEFS.h"
37
38/*
39 * strcmp(s1, s2)
40 *	return an integer greater than, equal to, or less than 0,
41 *	according as string s1 is greater than, equal to, or less
42 *	than the string s2.
43 *
44 * %eax - pointer to s1
45 * %edx - pointer to s2
46 *
47 * Written by:
48 *	J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc.
49 */
50
51/*
52 * I've unrolled the loop eight times: large enough to make a
53 * significant difference, and small enough not to totally trash the
54 * cashe.
55 */
56
57ENTRY(strcmp)
58	movl	0x04(%esp),%eax
59	movl	0x08(%esp),%edx
60	jmp	L2			/* Jump into the loop! */
61
62	.align	2,0x90
63L1:	incl	%eax
64	incl	%edx
65L2:	movb	(%eax),%cl
66	testb	%cl,%cl
67	je	L3
68	cmpb	%cl,(%edx)
69	jne	L3
70	incl	%eax
71	incl	%edx
72	movb	(%eax),%cl
73	testb	%cl,%cl
74	je	L3
75	cmpb	%cl,(%edx)
76	jne	L3
77	incl	%eax
78	incl	%edx
79	movb	(%eax),%cl
80	testb	%cl,%cl
81	je	L3
82	cmpb	%cl,(%edx)
83	jne	L3
84	incl	%eax
85	incl	%edx
86	movb	(%eax),%cl
87	testb	%cl,%cl
88	je	L3
89	cmpb	%cl,(%edx)
90	jne	L3
91	incl	%eax
92	incl	%edx
93	movb	(%eax),%cl
94	testb	%cl,%cl
95	je	L3
96	cmpb	%cl,(%edx)
97	jne	L3
98	incl	%eax
99	incl	%edx
100	movb	(%eax),%cl
101	testb	%cl,%cl
102	je	L3
103	cmpb	%cl,(%edx)
104	jne	L3
105	incl	%eax
106	incl	%edx
107	movb	(%eax),%cl
108	testb	%cl,%cl
109	je	L3
110	cmpb	%cl,(%edx)
111	jne	L3
112	incl	%eax
113	incl	%edx
114	movb	(%eax),%cl
115	testb	%cl,%cl
116	je	L3
117	cmpb	%cl,(%edx)
118	je	L1
119	.align 2, 0x90
120L3:     movzbl  (%eax),%eax             /* unsigned comparison */
121	movzbl  (%edx),%edx
122	subl	%edx,%eax
123	ret
124