vpx_util/endian_inl.h

   1 // Copyright 2014 Google Inc. All Rights Reserved.
   2 //
   3 // Use of this source code is governed by a BSD-style license
   4 // that can be found in the COPYING file in the root of the source
   5 // tree. An additional intellectual property rights grant can be found
   6 // in the file PATENTS. All contributing project authors may
   7 // be found in the AUTHORS file in the root of the source tree.
   8 // -----------------------------------------------------------------------------
   9 //
  10 // Endian related functions.
  11
  12 #ifndef VPX_UTIL_ENDIAN_INL_H_
  13 #define VPX_UTIL_ENDIAN_INL_H_
  14
  15 #include <stdlib.h>
  16 #include "./vpx_config.h"
  17 #include "vpx/vpx_integer.h"
  18
  19 #if defined(__GNUC__)
  20 # define LOCAL_GCC_VERSION ((__GNUC__ << 8) | __GNUC_MINOR__)
  21 # define LOCAL_GCC_PREREQ(maj, min) \
  22     (LOCAL_GCC_VERSION >= (((maj) << 8) | (min)))
  23 #else
  24 # define LOCAL_GCC_VERSION 0
  25 # define LOCAL_GCC_PREREQ(maj, min) 0
  26 #endif
  27
  28 #ifdef __clang__
  29 # define LOCAL_CLANG_VERSION ((__clang_major__ << 8) | __clang_minor__)
  30 # define LOCAL_CLANG_PREREQ(maj, min) \
  31     (LOCAL_CLANG_VERSION >= (((maj) << 8) | (min)))
  32 #else
  33 # define LOCAL_CLANG_VERSION 0
  34 # define LOCAL_CLANG_PREREQ(maj, min) 0
  35 #endif  // __clang__
  36
  37 // some endian fix (e.g.: mips-gcc doesn't define __BIG_ENDIAN__)
  38 #if !defined(WORDS_BIGENDIAN) && \
  39     (defined(__BIG_ENDIAN__) || defined(_M_PPC) || \
  40      (defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)))
  41 #define WORDS_BIGENDIAN
  42 #endif
  43
  44 #if defined(WORDS_BIGENDIAN)
  45 #define HToLE32 BSwap32
  46 #define HToLE16 BSwap16
  47 #define HToBE64(x) (x)
  48 #define HToBE32(x) (x)
  49 #else
  50 #define HToLE32(x) (x)
  51 #define HToLE16(x) (x)
  52 #define HToBE64(X) BSwap64(X)
  53 #define HToBE32(X) BSwap32(X)
  54 #endif
  55
  56 // clang-3.3 and gcc-4.3 have builtin functions for swap32/swap64
  57 #if LOCAL_GCC_PREREQ(4, 3) || LOCAL_CLANG_PREREQ(3, 3)
  58 #define HAVE_BUILTIN_BSWAP32
  59 #define HAVE_BUILTIN_BSWAP64
  60 #endif
  61 // clang-3.3 and gcc-4.8 have a builtin function for swap16
  62 #if LOCAL_GCC_PREREQ(4, 8) || LOCAL_CLANG_PREREQ(3, 3)
  63 #define HAVE_BUILTIN_BSWAP16
  64 #endif
  65
  66 static INLINE uint16_t BSwap16(uint16_t x) {
  67 #if defined(HAVE_BUILTIN_BSWAP16)
  68   return __builtin_bswap16(x);
  69 #elif defined(_MSC_VER)
  70   return _byteswap_ushort(x);
  71 #else
  72   // gcc will recognize a 'rorw $8, ...' here:
  73   return (x >> 8) | ((x & 0xff) << 8);
  74 #endif  // HAVE_BUILTIN_BSWAP16
  75 }
  76
  77 static INLINE uint32_t BSwap32(uint32_t x) {
  78 #if HAVE_MIPS32
  79   uint32_t ret;
  80   __asm__ volatile (
  81     "wsbh   %[ret], %[x]          \n\t"
  82     "rotr   %[ret], %[ret],  16   \n\t"
  83     : [ret]"=r"(ret)
  84     : [x]"r"(x)
  85   );
  86   return ret;
  87 #elif defined(HAVE_BUILTIN_BSWAP32)
  88   return __builtin_bswap32(x);
  89 #elif defined(__i386__) || defined(__x86_64__)
  90   uint32_t swapped_bytes;
  91   __asm__ volatile("bswap %0" : "=r"(swapped_bytes) : "0"(x));
  92   return swapped_bytes;
  93 #elif defined(_MSC_VER)
  94   return (uint32_t)_byteswap_ulong(x);
  95 #else
  96   return (x >> 24) | ((x >> 8) & 0xff00) | ((x << 8) & 0xff0000) | (x << 24);
  97 #endif  // HAVE_BUILTIN_BSWAP32
  98 }
  99
 100 static INLINE uint64_t BSwap64(uint64_t x) {
 101 #if defined(HAVE_BUILTIN_BSWAP64)
 102   return __builtin_bswap64(x);
 103 #elif defined(__x86_64__)
 104   uint64_t swapped_bytes;
 105   __asm__ volatile("bswapq %0" : "=r"(swapped_bytes) : "0"(x));
 106   return swapped_bytes;
 107 #elif defined(_MSC_VER)
 108   return (uint64_t)_byteswap_uint64(x);
 109 #else  // generic code for swapping 64-bit values (suggested by bdb@)
 110   x = ((x & 0xffffffff00000000ull) >> 32) | ((x & 0x00000000ffffffffull) << 32);
 111   x = ((x & 0xffff0000ffff0000ull) >> 16) | ((x & 0x0000ffff0000ffffull) << 16);
 112   x = ((x & 0xff00ff00ff00ff00ull) >>  8) | ((x & 0x00ff00ff00ff00ffull) <<  8);
 113   return x;
 114 #endif  // HAVE_BUILTIN_BSWAP64
 115 }
 116
 117 #endif  // VPX_UTIL_ENDIAN_INL_H_