xref: /titanic_52/usr/src/lib/libbc/libc/gen/common/swab.c (revision 7c478bd95313f5f23a4c958a745db2134aa03244)

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 1989 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident	"%Z%%M%	%I%	%E% SMI"
	  /* from UCB 4.2 83/06/27 */

/*
 * Swab bytes
 * Jeffrey Mogul, Stanford
 */

void
swab(from, to, n)
	register char *from, *to;
	register int n;
{
	register unsigned long temp;

	if (n <= 1)
		return;
	n >>= 1; n++;
#define	STEP	temp = *from++,*to++ = *from++,*to++ = temp
	/* round to multiple of 8 */
	while ((--n) & 07)
		STEP;
	n >>= 3;
	while (--n >= 0) {
		STEP; STEP; STEP; STEP;
		STEP; STEP; STEP; STEP;
	}
}