xref: /minix3/common/lib/libc/arch/alpha/gen/byte_swap_4.S (revision b6cbf7203b080219de306404f8022a65b7884f33)
1*b6cbf720SGianluca Guida/* $NetBSD: byte_swap_4.S,v 1.3 2008/02/16 17:37:13 apb Exp $ */
2*b6cbf720SGianluca Guida
3*b6cbf720SGianluca Guida/*
4*b6cbf720SGianluca Guida * Copyright (c) 1996 Carnegie-Mellon University.
5*b6cbf720SGianluca Guida * All rights reserved.
6*b6cbf720SGianluca Guida *
7*b6cbf720SGianluca Guida * Author: Chris G. Demetriou
8*b6cbf720SGianluca Guida *
9*b6cbf720SGianluca Guida * Permission to use, copy, modify and distribute this software and
10*b6cbf720SGianluca Guida * its documentation is hereby granted, provided that both the copyright
11*b6cbf720SGianluca Guida * notice and this permission notice appear in all copies of the
12*b6cbf720SGianluca Guida * software, derivative works or modified versions, and any portions
13*b6cbf720SGianluca Guida * thereof, and that both notices appear in supporting documentation.
14*b6cbf720SGianluca Guida *
15*b6cbf720SGianluca Guida * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
16*b6cbf720SGianluca Guida * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
17*b6cbf720SGianluca Guida * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
18*b6cbf720SGianluca Guida *
19*b6cbf720SGianluca Guida * Carnegie Mellon requests users of this software to return to
20*b6cbf720SGianluca Guida *
21*b6cbf720SGianluca Guida *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
22*b6cbf720SGianluca Guida *  School of Computer Science
23*b6cbf720SGianluca Guida *  Carnegie Mellon University
24*b6cbf720SGianluca Guida *  Pittsburgh PA 15213-3890
25*b6cbf720SGianluca Guida *
26*b6cbf720SGianluca Guida * any improvements or extensions that they make and grant Carnegie the
27*b6cbf720SGianluca Guida * rights to redistribute these changes.
28*b6cbf720SGianluca Guida */
29*b6cbf720SGianluca Guida
30*b6cbf720SGianluca Guida#include <machine/asm.h>
31*b6cbf720SGianluca Guida
32*b6cbf720SGianluca Guida/*
33*b6cbf720SGianluca Guida * Byte-swap a 4-byte quantity.  (Convert 0x01234567 to 0x67452301.)
34*b6cbf720SGianluca Guida *
35*b6cbf720SGianluca Guida * Argument is an unsigned 4-byte integer (uint32_t).
36*b6cbf720SGianluca Guida */
37*b6cbf720SGianluca Guida#if defined(_KERNEL) || defined(_STANDALONE)
38*b6cbf720SGianluca Guida#define	BSWAP32	bswap32
39*b6cbf720SGianluca Guida#else /* defined(_KERNEL) || defined(_STANDALONE) */
40*b6cbf720SGianluca Guida#define	BSWAP32	__bswap32
41*b6cbf720SGianluca Guida#endif /* defined(_KERNEL) || defined(_STANDALONE) */
42*b6cbf720SGianluca GuidaLEAF(BSWAP32, 1)		/* a0 contains 0x01234567 */
43*b6cbf720SGianluca GuidaXLEAF(htonl, 1)
44*b6cbf720SGianluca GuidaXLEAF(ntohl, 1)
45*b6cbf720SGianluca Guida	insbl	a0, 3, t0	/* t0 = 0x67       */
46*b6cbf720SGianluca Guida	extbl	a0, 1, t1	/* t1 = 0x      45 */
47*b6cbf720SGianluca Guida	extbl	a0, 2, t2	/* t2 = 0x      23 */
48*b6cbf720SGianluca Guida	extbl	a0, 3, t3	/* t3 = 0x      01 */
49*b6cbf720SGianluca Guida	sll	t1, 16, t1	/* t1 = 0x  45     */
50*b6cbf720SGianluca Guida	sll	t2, 8, t2	/* t2 = 0x    23   */
51*b6cbf720SGianluca Guida	or	t3, t0, v0	/* v0 = 0x67    01 */
52*b6cbf720SGianluca Guida	or	t1, t2, t1	/* t1 = 0x  4523   */
53*b6cbf720SGianluca Guida	or	t1, v0, v0	/* v0 = 0x67452301 */
54*b6cbf720SGianluca Guida	RET
55*b6cbf720SGianluca GuidaEND(BSWAP32)
56