1 /* $FreeBSD: src/sys/libkern/alpha/byte_swap_2.S,v 1.1.6.1 2000/08/03 01:03:45 peter Exp $ */
2 /* $NetBSD: byte_swap_2.S,v 1.2 1996/10/17 03:08:08 cgd Exp $ */
5 * Copyright (c) 1996 Carnegie-Mellon University.
8 * Author: Chris G. Demetriou
10 * Permission to use, copy, modify and distribute this software and
11 * its documentation is hereby granted, provided that both the copyright
12 * notice and this permission notice appear in all copies of the
13 * software, derivative works or modified versions, and any portions
14 * thereof, and that both notices appear in supporting documentation.
16 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
17 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
18 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
20 * Carnegie Mellon requests users of this software to return to
22 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
23 * School of Computer Science
24 * Carnegie Mellon University
25 * Pittsburgh PA 15213-3890
27 * any improvements or extensions that they make and grant Carnegie the
28 * rights to redistribute these changes.
31 #include <machine/asm.h>
34 #define NAME byte_swap_2
38 * Byte-swap a 2-byte quantity. (Convert 0x0123 to 0x2301.)
40 * Argument is an unsigned 2-byte integer (u_int16_t).
42 LEAF(NAME, 1) /* a0 contains 0x0123 */
43 extbl a0, 0, t0 /* t0 = 0x 23 */
44 extbl a0, 1, t1 /* t1 = 0x 01 */
45 sll t0, 8, t0 /* t1 = 0x23 */
46 or t0, t1, v0 /* v0 = 0x2301 */