xref: /onnv-gate/usr/src/lib/libbc/libc/gen/common/swab.c (revision 0:68f95e015346)
1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate  * CDDL HEADER START
3*0Sstevel@tonic-gate  *
4*0Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*0Sstevel@tonic-gate  * with the License.
8*0Sstevel@tonic-gate  *
9*0Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate  * and limitations under the License.
13*0Sstevel@tonic-gate  *
14*0Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate  *
20*0Sstevel@tonic-gate  * CDDL HEADER END
21*0Sstevel@tonic-gate  */
22*0Sstevel@tonic-gate /*
23*0Sstevel@tonic-gate  * Copyright 1989 Sun Microsystems, Inc.  All rights reserved.
24*0Sstevel@tonic-gate  * Use is subject to license terms.
25*0Sstevel@tonic-gate  */
26*0Sstevel@tonic-gate 
27*0Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"
28*0Sstevel@tonic-gate 	  /* from UCB 4.2 83/06/27 */
29*0Sstevel@tonic-gate 
30*0Sstevel@tonic-gate /*
31*0Sstevel@tonic-gate  * Swab bytes
32*0Sstevel@tonic-gate  * Jeffrey Mogul, Stanford
33*0Sstevel@tonic-gate  */
34*0Sstevel@tonic-gate 
35*0Sstevel@tonic-gate void
swab(from,to,n)36*0Sstevel@tonic-gate swab(from, to, n)
37*0Sstevel@tonic-gate 	register char *from, *to;
38*0Sstevel@tonic-gate 	register int n;
39*0Sstevel@tonic-gate {
40*0Sstevel@tonic-gate 	register unsigned long temp;
41*0Sstevel@tonic-gate 
42*0Sstevel@tonic-gate 	if (n <= 1)
43*0Sstevel@tonic-gate 		return;
44*0Sstevel@tonic-gate 	n >>= 1; n++;
45*0Sstevel@tonic-gate #define	STEP	temp = *from++,*to++ = *from++,*to++ = temp
46*0Sstevel@tonic-gate 	/* round to multiple of 8 */
47*0Sstevel@tonic-gate 	while ((--n) & 07)
48*0Sstevel@tonic-gate 		STEP;
49*0Sstevel@tonic-gate 	n >>= 3;
50*0Sstevel@tonic-gate 	while (--n >= 0) {
51*0Sstevel@tonic-gate 		STEP; STEP; STEP; STEP;
52*0Sstevel@tonic-gate 		STEP; STEP; STEP; STEP;
53*0Sstevel@tonic-gate 	}
54*0Sstevel@tonic-gate }
55