libavutil/bswap.h

   1 /*
   2  * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 /**
  22  * @file bswap.h
  23  * byte swap.
  24  */
  25
  26 #ifndef BSWAP_H
  27 #define BSWAP_H
  28
  29 #include <stdint.h>
  30 #include "common.h"
  31
  32 #ifdef HAVE_BYTESWAP_H
  33 #include <byteswap.h>
  34 #else
  35
  36 #ifdef ARCH_X86_64
  37 #  define LEGACY_REGS "=Q"
  38 #else
  39 #  define LEGACY_REGS "=q"
  40 #endif
  41
  42 static av_always_inline uint16_t bswap_16(uint16_t x)
  43 {
  44 #if defined(ARCH_X86)
  45   __asm("rorw $8, %0"   :
  46         LEGACY_REGS (x) :
  47         "0" (x));
  48 #elif defined(ARCH_SH4)
  49         __asm__("swap.b %0,%0":"=r"(x):"0"(x));
  50 #else
  51     x= (x>>8) | (x<<8);
  52 #endif
  53     return x;
  54 }
  55
  56 static av_always_inline uint32_t bswap_32(uint32_t x)
  57 {
  58 #if defined(ARCH_X86)
  59 #if __CPU__ != 386
  60  __asm("bswap   %0":
  61       "=r" (x)     :
  62 #else
  63  __asm("xchgb   %b0,%h0\n"
  64       "         rorl    $16,%0\n"
  65       "         xchgb   %b0,%h0":
  66       LEGACY_REGS (x)                :
  67 #endif
  68       "0" (x));
  69 #elif defined(ARCH_SH4)
  70         __asm__(
  71         "swap.b %0,%0\n"
  72         "swap.w %0,%0\n"
  73         "swap.b %0,%0\n"
  74         :"=r"(x):"0"(x));
  75 #elif defined(ARCH_ARM)
  76     uint32_t t;
  77     __asm__ (
  78       "eor %1, %0, %0, ror #16 \n\t"
  79       "bic %1, %1, #0xFF0000   \n\t"
  80       "mov %0, %0, ror #8      \n\t"
  81       "eor %0, %0, %1, lsr #8  \n\t"
  82       : "+r"(x), "+r"(t));
  83 #elif defined(ARCH_BFIN)
  84     unsigned tmp;
  85     asm("%1 = %0 >> 8 (V);\n\t"
  86         "%0 = %0 << 8 (V);\n\t"
  87         "%0 = %0 | %1;\n\t"
  88         "%0 = PACK(%0.L, %0.H);\n\t"
  89         : "+d"(x), "=&d"(tmp));
  90 #else
  91     x= ((x<<8)&0xFF00FF00) | ((x>>8)&0x00FF00FF);
  92     x= (x>>16) | (x<<16);
  93 #endif
  94     return x;
  95 }
  96
  97 static inline uint64_t bswap_64(uint64_t x)
  98 {
  99 #if 0
 100     x= ((x<< 8)&0xFF00FF00FF00FF00ULL) | ((x>> 8)&0x00FF00FF00FF00FFULL);
 101     x= ((x<<16)&0xFFFF0000FFFF0000ULL) | ((x>>16)&0x0000FFFF0000FFFFULL);
 102     return (x>>32) | (x<<32);
 103 #elif defined(ARCH_X86_64)
 104   __asm("bswap  %0":
 105         "=r" (x)   :
 106         "0" (x));
 107   return x;
 108 #else
 109     union {
 110         uint64_t ll;
 111         uint32_t l[2];
 112     } w, r;
 113     w.ll = x;
 114     r.l[0] = bswap_32 (w.l[1]);
 115     r.l[1] = bswap_32 (w.l[0]);
 116     return r.ll;
 117 #endif
 118 }
 119
 120 #endif  /* !HAVE_BYTESWAP_H */
 121
 122 // be2me ... BigEndian to MachineEndian
 123 // le2me ... LittleEndian to MachineEndian
 124
 125 #ifdef WORDS_BIGENDIAN
 126 #define be2me_16(x) (x)
 127 #define be2me_32(x) (x)
 128 #define be2me_64(x) (x)
 129 #define le2me_16(x) bswap_16(x)
 130 #define le2me_32(x) bswap_32(x)
 131 #define le2me_64(x) bswap_64(x)
 132 #else
 133 #define be2me_16(x) bswap_16(x)
 134 #define be2me_32(x) bswap_32(x)
 135 #define be2me_64(x) bswap_64(x)
 136 #define le2me_16(x) (x)
 137 #define le2me_32(x) (x)
 138 #define le2me_64(x) (x)
 139 #endif
 140
 141 #endif /* BSWAP_H */