48 lines
1.4 KiB
ArmAsm
48 lines
1.4 KiB
ArmAsm
/* $NetBSD: byte_swap_2.S,v 1.2 1996/10/17 03:08:08 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>
|
|
|
|
#ifndef NAME
|
|
#define NAME byte_swap_2
|
|
#endif
|
|
|
|
/*
|
|
* Byte-swap a 2-byte quantity. (Convert 0x0123 to 0x2301.)
|
|
*
|
|
* Argument is an unsigned 2-byte integer (u_int16_t).
|
|
*/
|
|
LEAF(NAME, 1) /* a0 contains 0x0123 */
|
|
extbl a0, 0, t0 /* t0 = 0x 23 */
|
|
extbl a0, 1, t1 /* t1 = 0x 01 */
|
|
sll t0, 8, t0 /* t1 = 0x23 */
|
|
or t0, t1, v0 /* v0 = 0x2301 */
|
|
RET
|
|
END(NAME)
|