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
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
|
/* $NetBSD: bcmp.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: @(#)bcmp.s 8.1 (Berkeley) 6/4/93")
ASMSTR("$NetBSD: bcmp.S,v 1.8 2003/08/07 16:42:16 agc Exp $")
#endif /* LIBC_SCCS and not lint */
#ifdef __ABICALLS__
.abicalls
#endif
/* bcmp(s1, s2, n) */
LEAF(bcmp)
.set noreorder
blt a2, 16, small # is it worth any trouble?
xor v0, a0, a1 # compare low two bits of addresses
and v0, v0, 3
subu a3, zero, a1 # compute # bytes to word align address
bne v0, zero, unaligned # not possible to align addresses
and a3, a3, 3
beq a3, zero, 1f
subu a2, a2, a3 # subtract from remaining count
move v0, v1 # init v0,v1 so unmodified bytes match
#ifdef __MIPSEB__
lwl v0, 0(a0) # read 1, 2, or 3 bytes
lwl v1, 0(a1)
#else
lwr v0, 0(a0) # read 1, 2, or 3 bytes
lwr v1, 0(a1)
#endif
addu a1, a1, a3
bne v0, v1, nomatch
addu a0, a0, a3
1:
and a3, a2, ~3 # compute number of whole words left
subu a2, a2, a3 # which has to be >= (16-3) & ~3
addu a3, a3, a0 # compute ending address
2:
lw v0, 0(a0) # compare words
lw v1, 0(a1)
addu a0, a0, 4
bne v0, v1, nomatch
addu a1, a1, 4
bne a0, a3, 2b
nop
b small # finish remainder
nop
unaligned:
beq a3, zero, 2f
subu a2, a2, a3 # subtract from remaining count
addu a3, a3, a0 # compute ending address
1:
lbu v0, 0(a0) # compare bytes until a1 word aligned
lbu v1, 0(a1)
addu a0, a0, 1
bne v0, v1, nomatch
addu a1, a1, 1
bne a0, a3, 1b
nop
2:
and a3, a2, ~3 # compute number of whole words left
subu a2, a2, a3 # which has to be >= (16-3) & ~3
addu a3, a3, a0 # compute ending address
3:
#ifdef __MIPSEB__
lwl v0, 0(a0) # compare words a0 unaligned, a1 aligned
lwr v0, 3(a0)
#else
lwr v0, 0(a0) # compare words a0 unaligned, a1 aligned
lwl v0, 3(a0)
#endif
lw v1, 0(a1)
addu a0, a0, 4
bne v0, v1, nomatch
addu a1, a1, 4
bne a0, a3, 3b
nop
small:
ble a2, zero, match
addu a3, a2, a0 # compute ending address
1:
lbu v0, 0(a0)
lbu v1, 0(a1)
addu a0, a0, 1
bne v0, v1, nomatch
addu a1, a1, 1
bne a0, a3, 1b
nop
match:
j ra
move v0, zero
nomatch:
j ra
li v0, 1
.set reorder
END(bcmp)
|
