1/* $NetBSD: byte_swap_4.S,v 1.6 2013/01/16 21:48:56 matt Exp $ */ 2 3/*- 4 * Copyright (c) 1997 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Neil A. Carson 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32#include <machine/asm.h> 33 34#if defined(_KERNEL) || defined(_STANDALONE) 35_ENTRY(_C_LABEL(bswap32)) 36#else 37_ENTRY(_C_LABEL(__bswap32)) 38#endif 39#if BYTE_ORDER == LITTLE_ENDIAN 40_ENTRY(_C_LABEL(ntohl)) 41_ENTRY(_C_LABEL(htonl)) 42#endif 43_PROF_PROLOGUE 44#ifdef _ARM_ARCH_6 45 rev r0, r0 46#else 47 eor r1, r0, r0, ror #16 /* 4.3.2.1 -> 42.31.42.31 */ 48 bic r1, r1, #0x00FF0000 /* 42.31.42.31 -> 42.0.42.31 */ 49 mov r0, r0, ror #8 /* 4.3.2.1 -> 1.4.3.2 */ 50 eor r0, r0, r1, lsr #8 /* 1.4.3.2 ^ 0.42.0.42 -> 1.2.3.4 */ 51#endif 52 RET 53