xref: /netbsd-src/common/lib/libc/arch/arm/gen/byte_swap_4.S (revision 53166c520aa3a0e56f56753c66a30623d99c14cf)
1*53166c52Sdholland/*	$NetBSD: byte_swap_4.S,v 1.9 2020/12/11 09:02:33 dholland Exp $	*/
237c9f0a6Schristos
337c9f0a6Schristos/*-
437c9f0a6Schristos * Copyright (c) 1997 The NetBSD Foundation, Inc.
537c9f0a6Schristos * All rights reserved.
637c9f0a6Schristos *
737c9f0a6Schristos * This code is derived from software contributed to The NetBSD Foundation
837c9f0a6Schristos * by Neil A. Carson
937c9f0a6Schristos *
1037c9f0a6Schristos * Redistribution and use in source and binary forms, with or without
1137c9f0a6Schristos * modification, are permitted provided that the following conditions
1237c9f0a6Schristos * are met:
1337c9f0a6Schristos * 1. Redistributions of source code must retain the above copyright
1437c9f0a6Schristos *    notice, this list of conditions and the following disclaimer.
1537c9f0a6Schristos * 2. Redistributions in binary form must reproduce the above copyright
1637c9f0a6Schristos *    notice, this list of conditions and the following disclaimer in the
1737c9f0a6Schristos *    documentation and/or other materials provided with the distribution.
1837c9f0a6Schristos *
1937c9f0a6Schristos * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
2037c9f0a6Schristos * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
2137c9f0a6Schristos * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
2237c9f0a6Schristos * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
2337c9f0a6Schristos * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
2437c9f0a6Schristos * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
2537c9f0a6Schristos * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
2637c9f0a6Schristos * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
2737c9f0a6Schristos * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
2837c9f0a6Schristos * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
2937c9f0a6Schristos * POSSIBILITY OF SUCH DAMAGE.
3037c9f0a6Schristos */
3137c9f0a6Schristos
3237c9f0a6Schristos#include <machine/asm.h>
3337c9f0a6Schristos
34c61d2c64Suwe#if defined(_KERNEL) || defined(_STANDALONE)
3514ba29f9Smatt#define	FUNC	_C_LABEL(bswap32)
36c61d2c64Suwe#else
3714ba29f9Smatt#define	FUNC	_C_LABEL(__bswap32)
38c61d2c64Suwe#endif
3914ba29f9SmattENTRY(FUNC)
40a96852fcSmatt#ifdef _ARM_ARCH_6
41a96852fcSmatt	rev	r0, r0
4214ba29f9Smatt#elif !defined(__thumb__)
433818c9a2Sdholland	eor	r1, r0, r0, ror #16	/* d.c.b.a -> db.ca.db.ca */
443818c9a2Sdholland	bic	r1, r1, #0x00FF0000	/* db.ca.db.ca -> db.0.db.ca */
453818c9a2Sdholland	mov	r0, r0, ror #8		/* d.c.b.a -> a.d.c.b */
463818c9a2Sdholland	eor	r0, r0, r1, lsr #8	/* a.d.c.b ^ 0.db.0.db -> a.b.c.d */
4714ba29f9Smatt#else
4814ba29f9Smatt	movs	r3, #16
49*53166c52Sdholland	lsls	r1, r0, #8		/* d.c.b.a -> c.b.a.0 */
503818c9a2Sdholland	lsrs	r0, r0, #8		/* d.c.b.a -> 0.d.c.b */
513818c9a2Sdholland	rors	r1, r3			/* c.b.a.0 -> a.0.c.b */
523818c9a2Sdholland	rors	r0, r3			/* 0.d.c.b -> c.b.0.d */
533818c9a2Sdholland	lsrs	r1, r1, #8		/* a.0.c.b -> 0.a.0.c */
543818c9a2Sdholland	lsls	r1, r1, #8		/* 0.a.0.c -> a.0.c.0 */
553818c9a2Sdholland	lsls	r0, r0, #8		/* c.b.0.d -> b.0.d.0 */
563818c9a2Sdholland	lsrs	r0, r0, #8		/* b.0.d.0 -> 0.b.0.d */
573818c9a2Sdholland	orrs	r0, r0, r1		/* a.0.c.0 | 0.b.0.d -> a.b.c.d */
58a96852fcSmatt#endif
5937c9f0a6Schristos	RET
6014ba29f9SmattEND(FUNC)
6114ba29f9Smatt
6214ba29f9Smatt#if BYTE_ORDER == LITTLE_ENDIAN
6314ba29f9SmattSTRONG_ALIAS(_C_LABEL(ntohl), FUNC)
6414ba29f9SmattSTRONG_ALIAS(_C_LABEL(htonl), FUNC)
6514ba29f9Smatt#endif
66