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/* $OpenBSD: byte_swap_4.S,v 1.3 1996/11/13 22:05:03 niklas Exp $ */
/* $NetBSD: byte_swap_4.S,v 1.2 1996/10/17 03:08:09 cgd Exp $ */
/*
* Copyright (c) 1996 Carnegie-Mellon University.
* All rights reserved.
*
* Author: Chris G. Demetriou
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
#include <machine/asm.h>
#if defined(LIBC_SCCS)
.text
.asciz "$OpenBSD: byte_swap_4.S,v 1.3 1996/11/13 22:05:03 niklas Exp $"
#endif
#ifndef NAME
#define NAME byte_swap_4
#endif
/*
* Byte-swap a 4-byte quantity. (Convert 0x01234567 to 0x67452301.)
*
* Argument is an unsigned 4-byte integer (u_int32_t).
*/
LEAF(NAME, 1) /* a0 contains 0x01234567 */
extbl a0, 0, t0 /* t0 = 0x 67 */
extbl a0, 1, t1 /* t1 = 0x 45 */
extbl a0, 2, t2 /* t2 = 0x 23 */
extbl a0, 3, t3 /* t3 = 0x 01 */
sll t0, 24, t0 /* t0 = 0x67 */
sll t1, 16, t1 /* t1 = 0x 45 */
sll t2, 8, t2 /* t2 = 0x 23 */
or t3, t0, v0 /* v0 = 0x67 01 */
or t1, t2, t1 /* t1 = 0x 4523 */
or t1, v0, v0 /* v0 = 0x67452301 */
RET
END(NAME)
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