sys/arch/arm/include/byte_swap.h

   1 /*      $NetBSD: byte_swap.h,v 1.7 2008/04/27 18:58:44 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 __GNUC__
  36 #include <sys/types.h>
  37 __BEGIN_DECLS
  38
  39 #define __BYTE_SWAP_U32_VARIABLE __byte_swap_u32_variable
  40 static __inline uint32_t
  41 __byte_swap_u32_variable(uint32_t v)
  42 {
  43 #ifdef _ARM_ARCH_6
  44         __asm("rev\t%0, %1" : "=r" (v) : "0" (v));
  45 #else
  46         uint32_t t1;
  47
  48         t1 = v ^ ((v << 16) | (v >> 16));
  49         t1 &= 0xff00ffffU;
  50         v = (v >> 8) | (v << 24);
  51         v ^= (t1 >> 8);
  52 #endif
  53         return (v);
  54 }
  55
  56 #define __BYTE_SWAP_U16_VARIABLE __byte_swap_u16_variable
  57 static __inline uint16_t
  58 __byte_swap_u16_variable(uint16_t v)
  59 {
  60
  61 #ifdef _ARM_ARCH_6
  62         __asm("rev16\t%0, %1" : "=r" (v) : "0" (v));
  63 #elif !defined(__thumb__)
  64         __asm volatile(
  65                 "mov    %0, %1, ror #8\n"
  66                 "orr    %0, %0, %0, lsr #16\n"
  67                 "bic    %0, %0, %0, lsl #16"
  68         : "=r" (v)
  69         : "0" (v));
  70 #else
  71         v &= 0xffff;
  72         v = (v >> 8) | (v << 8);
  73 #endif
  74
  75         return (v);
  76 }
  77
  78 __END_DECLS
  79 #endif
  80
  81
  82 #endif /* _ARM_BYTE_SWAP_H_ */