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      1 /* $NetBSD: byte_swap.h,v 1.4 2017/01/17 11:09:36 rin Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2014 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Matt Thomas of 3am Software Foundry.
      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 __aarch64__
     36 
     37 #ifdef _LOCORE
     38 
     39 #define	BSWAP16(_src, _dst)		\
     40 	rev16	_dst, _src
     41 #define	BSWAP32(_src, _dst)		\
     42 	rev	_dst, _src
     43 #define	BSWAP64(_src, _dst)		\
     44 	rev	_dst, _src
     45 
     46 #else
     47 
     48 #ifdef __GNUC__
     49 #include <sys/types.h>
     50 __BEGIN_DECLS
     51 
     52 #define	__BYTE_SWAP_U64_VARIABLE __byte_swap_u64_variable
     53 static __inline uint64_t
     54 __byte_swap_u64_variable(uint64_t v)
     55 {
     56 	if (!__builtin_constant_p(v)) {
     57 		__asm("rev\t%x0, %x1" : "=r" (v) : "0" (v));
     58 		return v;
     59 	}
     60 
     61 	v =   ((v & 0x000000ff) << (56 -  0)) | ((v >> (56 -  0)) & 0x000000ff)
     62 	    | ((v & 0x0000ff00) << (48 -  8)) | ((v >> (48 -  8)) & 0x0000ff00)
     63 	    | ((v & 0x00ff0000) << (40 - 16)) | ((v >> (40 - 16)) & 0x00ff0000)
     64 	    | ((v & 0xff000000) << (32 - 24)) | ((v >> (32 - 24)) & 0xff000000);
     65 
     66 	return v;
     67 }
     68 
     69 #define	__BYTE_SWAP_U32_VARIABLE __byte_swap_u32_variable
     70 static __inline uint32_t
     71 __byte_swap_u32_variable(uint32_t v)
     72 {
     73 	if (!__builtin_constant_p(v)) {
     74 		__asm("rev\t%w0, %w1" : "=r" (v) : "0" (v));
     75 		return v;
     76 	}
     77 
     78 	v =   ((v & 0x00ff) << (24 - 0)) | ((v >> (24 - 0)) & 0x00ff)
     79 	    | ((v & 0xff00) << (16 - 8)) | ((v >> (16 - 8)) & 0xff00);
     80 
     81 	return v;
     82 }
     83 
     84 #define	__BYTE_SWAP_U16_VARIABLE __byte_swap_u16_variable
     85 static __inline uint16_t
     86 __byte_swap_u16_variable(uint16_t v)
     87 {
     88 
     89 	if (!__builtin_constant_p(v)) {
     90 		uint32_t v32 = v;
     91 		__asm("rev16\t%w0, %w1" : "=r" (v32) : "0" (v32));
     92 		return (uint16_t)v32;
     93 	}
     94 
     95 	v &= 0xffff;
     96 	v = (uint16_t)((v >> 8) | (v << 8));
     97 
     98 	return v;
     99 }
    100 
    101 __END_DECLS
    102 #endif
    103 
    104 #endif	/* _LOCORE */
    105 
    106 #elif defined(__arm__)
    107 
    108 #include <arm/asm.h>
    109 
    110 #endif
    111 
    112 #endif /* _ARM_BYTE_SWAP_H_ */
    113