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byte_swap.h revision 1.6.50.1 
      1 /*	$NetBSD: byte_swap.h,v 1.6.50.1 2007/08/28 16:55:50 matt Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1997, 1999, 2002 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, Neil A. Carson, and Jason R. Thorpe.
      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  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *	This product includes software developed by the NetBSD
     21  *	Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 #ifndef _ARM_BYTE_SWAP_H_
     40 #define	_ARM_BYTE_SWAP_H_
     41 
     42 #ifdef __GNUC__
     43 #include <sys/types.h>
     44 __BEGIN_DECLS
     45 
     46 #define	__BYTE_SWAP_U32_VARIABLE __byte_swap_u32_variable
     47 static __inline uint32_t
     48 __byte_swap_u32_variable(uint32_t v)
     49 {
     50 #ifdef _ARM_ARCH_6
     51 	__asm("rev\t%0, %1" : "=r"(v) : "r"(v));
     52 #else
     53 	uint32_t t1;
     54 
     55 	t1 = v ^ ((v << 16) | (v >> 16));
     56 	t1 &= 0xff00ffffU;
     57 	v = (v >> 8) | (v << 24);
     58 	v ^= (t1 >> 8);
     59 #endif
     60 	return (v);
     61 }
     62 
     63 #define	__BYTE_SWAP_U16_VARIABLE __byte_swap_u16_variable
     64 static __inline uint16_t
     65 __byte_swap_u16_variable(uint16_t v)
     66 {
     67 #ifdef _ARM_ARCH_6
     68 	__asm("rev16\t%0, %1" : "=r"(v) : "r"(v));
     69 #else
     70 	__asm volatile(
     71 		"mov	%0, %1, ror #8\n"
     72 		"orr	%0, %0, %0, lsr #16\n"
     73 		"bic	%0, %0, %0, lsl #16"
     74 	: "=r" (v)
     75 	: "0" (v));
     76 #endif
     77 	return (v);
     78 }
     79 
     80 __END_DECLS
     81 #endif
     82 
     83 
     84 #endif /* _ARM_BYTE_SWAP_H_ */
     85