minix/common/lib/libc/arch/arm/gen/byte_swap_4.S

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/* $NetBSD: byte_swap_4.S,v 1.7 2013/08/19 03:44:47 matt Exp $ */
/*-
* Copyright (c) 1997 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Neil A. Carson
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <machine/asm.h>
#if defined(_KERNEL) || defined(_STANDALONE)
#define FUNC _C_LABEL(bswap32)
#else
#define FUNC _C_LABEL(__bswap32)
#endif
ENTRY(FUNC)
#ifdef _ARM_ARCH_6
rev r0, r0
#elif !defined(__thumb__)
eor r1, r0, r0, ror #16 /* 4.3.2.1 -> 42.31.42.31 */
bic r1, r1, #0x00FF0000 /* 42.31.42.31 -> 42.0.42.31 */
mov r0, r0, ror #8 /* 4.3.2.1 -> 1.4.3.2 */
eor r0, r0, r1, lsr #8 /* 1.4.3.2 ^ 0.42.0.42 -> 1.2.3.4 */
#else
movs r3, #16
lsls r1, r0, #8 /* 4.3.2.1 -> 3.2.1.0 /*
lsrs r0, r0, #8 /* 4.3.2.1 -> 0.4.3.2 */
rors r1, r3 /* 3.2.1.0 -> 1.0.3.2 */
rors r0, r3 /* 0.4.3.2 -> 3.2.0.4 */
lsrs r1, r1, #8 /* 1.0.3.2 -> 0.1.0.3 */
lsls r1, r1, #8 /* 0.1.0.3 -> 1.0.3.0 */
lsls r0, r0, #8 /* 3.2.0.4 -> 2.0.4.0 */
lsrs r0, r0, #8 /* 2.0.4.0 -> 0.2.0.4 */
orrs r0, r0, r1 /* 1.0.3.0 | 0.2.0.4 -> 1.2.3.4 */
#endif
RET
END(FUNC)
#if BYTE_ORDER == LITTLE_ENDIAN
STRONG_ALIAS(_C_LABEL(ntohl), FUNC)
STRONG_ALIAS(_C_LABEL(htonl), FUNC)
#endif