bzero.S (7e546392b5fe3a496acff53ac7aadd1c57b2a4cf) bzero.S (662909a7800d5634772b89ca1509765dda837508)
1/*
2 * Copyright (c) 1993 Winning Strategies, Inc.
3 * All rights reserved.
1/*-
2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
4 *
5 * This code is derived from software contributed to Berkeley by
6 * William Jolitz.
7 *
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:
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * 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 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
18 *
23 *
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 * $Id$
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
31 */
32
35 */
36
33#if defined(LIBC_RCS) && !defined(lint)
34 .text
35 .asciz "$Id$"
36#endif /* LIBC_RCS and not lint */
37#if defined(LIBC_SCCS) && !defined(lint)
38 .asciz "@(#)bzero.s 8.1 (Berkeley) 6/4/93"
39#endif /* LIBC_SCCS and not lint */
37
40
38#include "DEFS.h"
41/* bzero (base,cnt) */
39
42
40/*
41 * bzero (void *b, size_t len)
42 * write len zero bytes to the string b.
43 *
44 * Written by:
45 * J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc.
46 */
47
48ENTRY(bzero)
43 .globl _bzero
44_bzero:
49 pushl %edi
45 pushl %edi
50 pushl %ebx
51 movl 12(%esp),%edi
52 movl 16(%esp),%ecx
53
54 cld /* set fill direction forward */
55 xorl %eax,%eax /* set fill data to 0 */
56
57 /*
58 * if the string is too short, it's really not worth the overhead
59 * of aligning to word boundries, etc. So we jump to a plain
60 * unaligned set.
61 */
62 cmpl $0x0f,%ecx
63 jle L1
64
65 movl %edi,%edx /* compute misalignment */
66 negl %edx
67 andl $3,%edx
68 movl %ecx,%ebx
69 subl %edx,%ebx
70
71 movl %edx,%ecx /* zero until word aligned */
46 movl 8(%esp),%edi
47 movl 12(%esp),%ecx
48 movb $0x00,%al
49 cld
72 rep
73 stosb
50 rep
51 stosb
74
75 movl %ebx,%ecx /* zero by words */
76 shrl $2,%ecx
77 rep
78 stosl
79
80 movl %ebx,%ecx
81 andl $3,%ecx /* zero remainder by bytes */
82L1: rep
83 stosb
84
85 popl %ebx
86 popl %edi
87 ret
52 popl %edi
53 ret