1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
|
/* $NetBSD: bzero.S,v 1.8 2003/08/07 16:42:16 agc Exp $ */
/*-
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Ralph Campbell.
*
* 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. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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("$FreeBSD$");
#if defined(LIBC_SCCS) && !defined(lint)
ASMSTR("from: @(#)bzero.s 8.1 (Berkeley) 6/4/93")
ASMSTR("$NetBSD: bzero.S,v 1.8 2003/08/07 16:42:16 agc Exp $")
#endif /* LIBC_SCCS and not lint */
#ifdef __ABICALLS__
.abicalls
#endif
/* bzero(s1, n) */
LEAF(bzero)
.set noreorder
blt a1, 12, smallclr # small amount to clear?
subu a3, zero, a0 # compute # bytes to word align address
and a3, a3, 3
beq a3, zero, 1f # skip if word aligned
subu a1, a1, a3 # subtract from remaining count
#ifdef __MIPSEB__
swl zero, 0(a0) # clear 1, 2, or 3 bytes to align
#else
swr zero, 0(a0) # clear 1, 2, or 3 bytes to align
#endif
addu a0, a0, a3
1:
and v0, a1, 3 # compute number of words left
subu a3, a1, v0
move a1, v0
addu a3, a3, a0 # compute ending address
2:
addu a0, a0, 4 # clear words
bne a0, a3, 2b # unrolling loop doesnt help
sw zero, -4(a0) # since we are limited by memory speed
smallclr:
ble a1, zero, 2f
addu a3, a1, a0 # compute ending address
1:
addu a0, a0, 1 # clear bytes
bne a0, a3, 1b
sb zero, -1(a0)
2:
j ra
nop
END(bzero)
|
