xref: /titanic_41/usr/src/lib/libbc/libc/gen/common/swab.c (revision 355b4669e025ff377602b6fc7caaf30dbc218371)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 1989 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 	  /* from UCB 4.2 83/06/27 */
29 
30 /*
31  * Swab bytes
32  * Jeffrey Mogul, Stanford
33  */
34 
35 void
36 swab(from, to, n)
37 	register char *from, *to;
38 	register int n;
39 {
40 	register unsigned long temp;
41 
42 	if (n <= 1)
43 		return;
44 	n >>= 1; n++;
45 #define	STEP	temp = *from++,*to++ = *from++,*to++ = temp
46 	/* round to multiple of 8 */
47 	while ((--n) & 07)
48 		STEP;
49 	n >>= 3;
50 	while (--n >= 0) {
51 		STEP; STEP; STEP; STEP;
52 		STEP; STEP; STEP; STEP;
53 	}
54 }
55