1 /* $NetBSD: bzero.S,v 1.2 2008/04/28 20:22:52 martin Exp $ */
4 * Copyright (c) 1997 The NetBSD Foundation, Inc.
7 * This code is derived from software contributed to The NetBSD Foundation
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
33 * Copyright (c) 1990 The Regents of the University of California.
34 * All rights reserved.
36 * This code is derived from software contributed to Berkeley by
37 * the Systems Programming Group of the University of Utah Computer
40 * Redistribution and use in source and binary forms, with or without
41 * modification, are permitted provided that the following conditions
43 * 1. Redistributions of source code must retain the above copyright
44 * notice, this list of conditions and the following disclaimer.
45 * 2. Redistributions in binary form must reproduce the above copyright
46 * notice, this list of conditions and the following disclaimer in the
47 * documentation and/or other materials provided with the distribution.
48 * 3. Neither the name of the University nor the names of its contributors
49 * may be used to endorse or promote products derived from this software
50 * without specific prior written permission.
52 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
53 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
54 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
55 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
56 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
57 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
58 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
59 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
60 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
61 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
65 #include <machine/asm.h>
67 #if defined(LIBC_SCCS) && !defined(lint)
69 RCSID("from: @(#)bzero.s 5.1 (Berkeley) 5/12/90")
71 RCSID("$NetBSD: bzero.S,v 1.2 2008/04/28 20:22:52 martin Exp $")
73 #endif /* LIBC_SCCS and not lint */
77 movl %sp@(8),%a0 | destination
78 movl %sp@(12),%d1 | count
83 * It isn't worth the overhead of aligning to {long}word boundries
84 * if the string is too short.
91 btst #0,%d0 | if (dst & 1)
93 movb %d2,%a0@+ | *(char *)dst++ = 0
97 btst #1,%d0 | if (dst & 2)
99 movw %d2,%a0@+ | *(short *)dst++ = 0
100 subql #2,%d1 | len -= 2
102 /* zero by 8 longwords */
104 lsrl #5,%d0 | cnt = len / 32
105 jeq Lbzlong | if (cnt)
106 andl #31,%d1 | len %= 32
107 subql #1,%d0 | set up for dbf
109 movl %d2,%a0@+ | zero 8 long words
117 dbf %d0,Lbz32loop | till done
123 /* copy by longwords */
125 lsrl #2,%d0 | cnt = len / 4
126 jeq Lbzbyte | if (cnt)
127 subql #1,%d0 | set up for dbf
129 movl %d2,%a0@+ | clear longwords
130 dbf %d0,Lbzlloop | till done
131 andl #3,%d1 | len %= 4
134 subql #1,%d1 | set up for dbf
136 movb %d2,%a0@+ | zero bytes
138 dbf %d1,Lbzbloop | till done