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byte_swap_2.S revision 1.6 
      1 /*	$NetBSD: byte_swap_2.S,v 1.6 2013/08/19 03:44:18 matt Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1999 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Charles M. Hannum.
      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(bswap16)
     36 #else
     37 #define FUNC _C_LABEL(__bswap16)
     38 #endif
     39 
     40 ENTRY(FUNC)
     41 #ifdef _ARM_ARCH_6
     42 	rev16		r0, r0
     43 #elif !defined(__thumb__)
     44 	and		r1, r0, #0xff
     45 	mov		r0, r0, lsr #8
     46 	orr		r0, r0, r1, lsl #8
     47 #else
     48 	movs		r2, #0xff
     49 	movs		r1, r0
     50 	ands		r1, r1, r2
     51 	lsls		r1, r1, #8
     52 	lsrs		r0, r0, #8
     53 	ands		r0, r0, r2
     54 	orrs		r0, r0, r1
     55 #endif
     56 	RET
     57 END(FUNC)
     58 #if BYTE_ORDER == LITTLE_ENDIAN
     59 STRONG_ALIAS(_C_LABEL(ntohs), FUNC)
     60 STRONG_ALIAS(_C_LABEL(htons), FUNC)
     61 #endif
     62