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byte_swap.h revision 1.8.18.1 
      1 /*	$NetBSD: byte_swap.h,v 1.8.18.1 2014/02/15 16:18:36 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  *
     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 #ifndef _ARM_BYTE_SWAP_H_
     33 #define	_ARM_BYTE_SWAP_H_
     34 
     35 #ifdef _LOCORE
     36 
     37 #if defined(_ARM_ARCH_6) || defined(_ARM_ARCH_7)
     38 
     39 #define	BSWAP16(_src, _dst, _tmp)		\
     40 	rev16	_dst, _src
     41 #define	BSWAP32(_src, _dst, _tmp)		\
     42 	rev	_dst, _src
     43 
     44 #else
     45 
     46 #define	BSWAP16(_src, _dst, _tmp)		\
     47 	mov	_tmp, _src, ror #8		;\
     48 	orr	_tmp, _tmp, _tmp, lsr #16	;\
     49 	bic	_dst, _tmp, _tmp, lsl #16
     50 
     51 #define	BSWAP32(_src, _dst, _tmp)		\
     52 	eor	_tmp, _src, _src, ror #16	;\
     53 	bic	_tmp, _tmp, #0x00FF0000		;\
     54 	mov	_dst, _src, ror #8		;\
     55 	eor	_dst, _dst, _tmp, lsr #8
     56 
     57 #endif
     58 
     59 
     60 #else
     61 
     62 #ifdef __GNUC__
     63 #include <sys/types.h>
     64 __BEGIN_DECLS
     65 
     66 #define	__BYTE_SWAP_U32_VARIABLE __byte_swap_u32_variable
     67 static __inline uint32_t
     68 __byte_swap_u32_variable(uint32_t v)
     69 {
     70 	uint32_t t1;
     71 
     72 #ifdef _ARM_ARCH_6
     73 	if (!__builtin_constant_p(v)) {
     74 		__asm("rev\t%0, %1" : "=r" (v) : "0" (v));
     75 		return v;
     76 	}
     77 #endif
     78 
     79 	t1 = v ^ ((v << 16) | (v >> 16));
     80 	t1 &= 0xff00ffffU;
     81 	v = (v >> 8) | (v << 24);
     82 	v ^= (t1 >> 8);
     83 
     84 	return (v);
     85 }
     86 
     87 #define	__BYTE_SWAP_U16_VARIABLE __byte_swap_u16_variable
     88 static __inline uint16_t
     89 __byte_swap_u16_variable(uint16_t v)
     90 {
     91 
     92 #ifdef _ARM_ARCH_6
     93 	if (!__builtin_constant_p(v)) {
     94 		uint32_t v32 = v;
     95 		__asm("rev16\t%0, %1" : "=r" (v32) : "0" (v32));
     96 		return v32;
     97 	}
     98 #elif !defined(__thumb__) && 0	/* gcc produces decent code for this */
     99 	if (!__builtin_constant_p(v)) {
    100 		uint32_t v0 = v;
    101 		__asm volatile(
    102 			"mov	%0, %1, ror #8\n"
    103 			"orr	%0, %0, %0, lsr #16\n"
    104 			"bic	%0, %0, %0, lsl #16"
    105 		: "=&r" (v0)
    106 		: "0" (v0));
    107 		return v0;
    108 	}
    109 #endif
    110 	v &= 0xffff;
    111 	v = (v >> 8) | (v << 8);
    112 
    113 	return (v);
    114 }
    115 
    116 __END_DECLS
    117 #endif
    118 
    119 #endif	/* _LOCORE */
    120 
    121 #endif /* _ARM_BYTE_SWAP_H_ */
    122