bswap.h

   1 /*
   2  * This file is part of FFmpeg.
   3  *
   4  * FFmpeg is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * FFmpeg is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with FFmpeg; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  17  */
  18
  19 #ifndef AVUTIL_ARM_BSWAP_H
  20 #define AVUTIL_ARM_BSWAP_H
  21
  22 #include <stdint.h>
  23 #include "config.h"
  24 #include "libavutil/attributes.h"
  25
  26 #ifdef __ARMCC_VERSION
  27
  28 #if HAVE_ARMV6
  29 #define av_bswap32 av_bswap32
  30 static av_always_inline av_const uint32_t av_bswap32(uint32_t x)
  31 {
  32     return __rev(x);
  33 }
  34 #endif /* HAVE_ARMV6 */
  35
  36 #elif HAVE_INLINE_ASM
  37
  38 #if HAVE_ARMV6_INLINE
  39 #define av_bswap16 av_bswap16
  40 static av_always_inline av_const unsigned av_bswap16(unsigned x)
  41 {
  42     __asm__("rev16 %0, %0" : "+r"(x));
  43     return x;
  44 }
  45 #endif
  46
  47 #if !AV_GCC_VERSION_AT_LEAST(4,5)
  48 #define av_bswap32 av_bswap32
  49 static av_always_inline av_const uint32_t av_bswap32(uint32_t x)
  50 {
  51 #if HAVE_ARMV6_INLINE
  52     __asm__("rev %0, %0" : "+r"(x));
  53 #else
  54     uint32_t t;
  55     __asm__ ("eor %1, %0, %0, ror #16 \n\t"
  56              "bic %1, %1, #0xFF0000   \n\t"
  57              "mov %0, %0, ror #8      \n\t"
  58              "eor %0, %0, %1, lsr #8  \n\t"
  59              : "+r"(x), "=&r"(t));
  60 #endif /* HAVE_ARMV6_INLINE */
  61     return x;
  62 }
  63 #endif /* !AV_GCC_VERSION_AT_LEAST(4,5) */
  64
  65 #endif /* __ARMCC_VERSION */
  66
  67 #endif /* AVUTIL_ARM_BSWAP_H */