libavutil/arm/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/common.h"
  25
  26 #ifdef __ARMCC_VERSION
  27
  28 #if HAVE_ARMV6
  29 #define bswap_16 bswap_16
  30 static av_always_inline av_const uint16_t bswap_16(uint16_t x)
  31 {
  32     __asm { rev16 x, x }
  33     return x;
  34 }
  35
  36 #define bswap_32 bswap_32
  37 static av_always_inline av_const uint32_t bswap_32(uint32_t x)
  38 {
  39     return __rev(x);
  40 }
  41 #endif /* HAVE_ARMV6 */
  42
  43 #elif HAVE_INLINE_ASM
  44
  45 #if HAVE_ARMV6
  46 #define bswap_16 bswap_16
  47 static av_always_inline av_const uint16_t bswap_16(uint16_t x)
  48 {
  49     __asm__("rev16 %0, %0" : "+r"(x));
  50     return x;
  51 }
  52 #endif
  53
  54 #define bswap_32 bswap_32
  55 static av_always_inline av_const uint32_t bswap_32(uint32_t x)
  56 {
  57 #if HAVE_ARMV6
  58     __asm__("rev %0, %0" : "+r"(x));
  59 #else
  60     uint32_t t;
  61     __asm__ ("eor %1, %0, %0, ror #16 \n\t"
  62              "bic %1, %1, #0xFF0000   \n\t"
  63              "mov %0, %0, ror #8      \n\t"
  64              "eor %0, %0, %1, lsr #8  \n\t"
  65              : "+r"(x), "=&r"(t));
  66 #endif /* HAVE_ARMV6 */
  67     return x;
  68 }
  69
  70 #endif /* __ARMCC_VERSION */
  71
  72 #endif /* AVUTIL_ARM_BSWAP_H */