Commit | Line | Data |
---|---|---|
4649a470 C |
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 | * | |
04af8261 | 30 | * $Id: memcmp.s,v 1.1 1993/08/16 18:40:33 jtc Exp $ |
4649a470 C |
31 | */ |
32 | ||
33 | #if defined(LIBC_RCS) && !defined(lint) | |
04af8261 | 34 | .asciz "$Id: memcmp.s,v 1.1 1993/08/16 18:40:33 jtc Exp $" |
4649a470 C |
35 | #endif /* LIBC_RCS and not lint */ |
36 | ||
37 | #include "DEFS.h" | |
38 | ||
39 | /* | |
40 | * memcmp (void *b1, void *b2, size_t len) | |
41 | * | |
42 | * Written by: | |
43 | * J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc. | |
44 | */ | |
45 | ||
4649a470 C |
46 | ENTRY(memcmp) |
47 | pushl %edi | |
48 | pushl %esi | |
49 | movl 12(%esp),%edi | |
50 | movl 16(%esp),%esi | |
04af8261 | 51 | movl 20(%esp),%edx |
4649a470 | 52 | cld /* set compare direction forward */ |
04af8261 DG |
53 | |
54 | movl %edx,%ecx /* compare by words */ | |
55 | shrl $2,%ecx | |
56 | repe | |
57 | cmpsl | |
58 | jne L5 /* do we match so far? */ | |
59 | ||
60 | movl %edx,%ecx /* compare remainder by bytes */ | |
61 | andl $3,%ecx | |
62 | repe | |
4649a470 | 63 | cmpsb |
04af8261 DG |
64 | jne L6 /* do we match? */ |
65 | ||
66 | xorl %eax,%eax /* we match, return zero */ | |
67 | popl %esi | |
68 | popl %edi | |
69 | ret | |
70 | ||
71 | L5: movl $4,%ecx /* We know that one of the next */ | |
72 | subl %ecx,%edi /* four pairs of bytes do not */ | |
73 | subl %ecx,%esi /* match. */ | |
74 | repe | |
75 | cmpsb | |
76 | L6: movsbl -1(%edi),%eax /* Perform unsigned comparison */ | |
4649a470 C |
77 | movsbl -1(%esi),%edx |
78 | subl %edx,%eax | |
04af8261 | 79 | popl %esi |
4649a470 C |
80 | popl %edi |
81 | ret |