1/*
2 * Copyright (c) 1993,94 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 without 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 */
30
31#include <machine/asm.h>
| 1/*
2 * Copyright (c) 1993,94 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 without 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 */
30
31#include <machine/asm.h>
|
32__FBSDID("$FreeBSD: head/lib/libc/i386/string/swab.S 108533 2003-01-01 18:49:04Z schweikh $");
| 32__FBSDID("$FreeBSD: head/lib/libc/i386/string/swab.S 184548 2008-11-02 01:28:47Z peter $");
|
33
34/*
35 * void
36 * swab (const void *src, void *dst, size_t len)
37 * copy len bytes from src to dst, swapping adjacent bytes
38 *
39 * On the i486, this code is negligibly faster than the code generated
40 * by gcc at about half the size. If my i386 databook is correct, it
41 * should be considerably faster than the gcc code on an i386.
42 *
43 * Written by:
44 * J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc.
45 */
46
47ENTRY(swab)
48 pushl %esi
49 pushl %edi
50 movl 12(%esp),%esi
51 movl 16(%esp),%edi
52 movl 20(%esp),%ecx
53
54 cld # set direction forward
55
56 shrl $1,%ecx
57 testl $7,%ecx # copy first group of 1 to 7 words
58 jz L2 # while swaping alternate bytes.
59 .align 2,0x90
60L1: lodsw
61 rorw $8,%ax
62 stosw
63 decl %ecx
64 testl $7,%ecx
65 jnz L1
66
67L2: shrl $3,%ecx # copy remainder 8 words at a time
68 jz L4 # while swapping alternate bytes.
69 .align 2,0x90
70L3: lodsw
71 rorw $8,%ax
72 stosw
73 lodsw
74 rorw $8,%ax
75 stosw
76 lodsw
77 rorw $8,%ax
78 stosw
79 lodsw
80 rorw $8,%ax
81 stosw
82 lodsw
83 rorw $8,%ax
84 stosw
85 lodsw
86 rorw $8,%ax
87 stosw
88 lodsw
89 rorw $8,%ax
90 stosw
91 lodsw
92 rorw $8,%ax
93 stosw
94 decl %ecx
95 jnz L3
96
97L4: popl %edi
98 popl %esi
99 ret
| 33
34/*
35 * void
36 * swab (const void *src, void *dst, size_t len)
37 * copy len bytes from src to dst, swapping adjacent bytes
38 *
39 * On the i486, this code is negligibly faster than the code generated
40 * by gcc at about half the size. If my i386 databook is correct, it
41 * should be considerably faster than the gcc code on an i386.
42 *
43 * Written by:
44 * J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc.
45 */
46
47ENTRY(swab)
48 pushl %esi
49 pushl %edi
50 movl 12(%esp),%esi
51 movl 16(%esp),%edi
52 movl 20(%esp),%ecx
53
54 cld # set direction forward
55
56 shrl $1,%ecx
57 testl $7,%ecx # copy first group of 1 to 7 words
58 jz L2 # while swaping alternate bytes.
59 .align 2,0x90
60L1: lodsw
61 rorw $8,%ax
62 stosw
63 decl %ecx
64 testl $7,%ecx
65 jnz L1
66
67L2: shrl $3,%ecx # copy remainder 8 words at a time
68 jz L4 # while swapping alternate bytes.
69 .align 2,0x90
70L3: lodsw
71 rorw $8,%ax
72 stosw
73 lodsw
74 rorw $8,%ax
75 stosw
76 lodsw
77 rorw $8,%ax
78 stosw
79 lodsw
80 rorw $8,%ax
81 stosw
82 lodsw
83 rorw $8,%ax
84 stosw
85 lodsw
86 rorw $8,%ax
87 stosw
88 lodsw
89 rorw $8,%ax
90 stosw
91 lodsw
92 rorw $8,%ax
93 stosw
94 decl %ecx
95 jnz L3
96
97L4: popl %edi
98 popl %esi
99 ret
|
| 100END(swab)
|
| |