1/* $NetBSD: byte_swap_4.S,v 1.9 2020/12/11 09:02:33 dholland 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#define FUNC _C_LABEL(bswap32) 36#else 37#define FUNC _C_LABEL(__bswap32) 38#endif 39ENTRY(FUNC) 40#ifdef _ARM_ARCH_6 41 rev r0, r0 42#elif !defined(__thumb__) 43 eor r1, r0, r0, ror #16 /* d.c.b.a -> db.ca.db.ca */ 44 bic r1, r1, #0x00FF0000 /* db.ca.db.ca -> db.0.db.ca */ 45 mov r0, r0, ror #8 /* d.c.b.a -> a.d.c.b */ 46 eor r0, r0, r1, lsr #8 /* a.d.c.b ^ 0.db.0.db -> a.b.c.d */ 47#else 48 movs r3, #16 49 lsls r1, r0, #8 /* d.c.b.a -> c.b.a.0 */ 50 lsrs r0, r0, #8 /* d.c.b.a -> 0.d.c.b */ 51 rors r1, r3 /* c.b.a.0 -> a.0.c.b */ 52 rors r0, r3 /* 0.d.c.b -> c.b.0.d */ 53 lsrs r1, r1, #8 /* a.0.c.b -> 0.a.0.c */ 54 lsls r1, r1, #8 /* 0.a.0.c -> a.0.c.0 */ 55 lsls r0, r0, #8 /* c.b.0.d -> b.0.d.0 */ 56 lsrs r0, r0, #8 /* b.0.d.0 -> 0.b.0.d */ 57 orrs r0, r0, r1 /* a.0.c.0 | 0.b.0.d -> a.b.c.d */ 58#endif 59 RET 60END(FUNC) 61 62#if BYTE_ORDER == LITTLE_ENDIAN 63STRONG_ALIAS(_C_LABEL(ntohl), FUNC) 64STRONG_ALIAS(_C_LABEL(htonl), FUNC) 65#endif 66