libavutil/float2half.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_FLOAT2HALF_H
  20 #define AVUTIL_FLOAT2HALF_H
  21
  22 #include <stdint.h>
  23 #include "intfloat.h"
  24
  25 #include "config.h"
  26
  27 typedef struct Float2HalfTables {
  28 #if HAVE_FAST_FLOAT16
  29     uint8_t dummy;
  30 #else
  31     uint16_t basetable[512];
  32     uint8_t shifttable[512];
  33 #endif
  34 } Float2HalfTables;
  35
  36 void ff_init_float2half_tables(Float2HalfTables *t);
  37
  38 static inline uint16_t float2half(uint32_t f, const Float2HalfTables *t)
  39 {
  40 #if HAVE_FAST_FLOAT16
  41     union {
  42         _Float16 f;
  43         uint16_t i;
  44     } u;
  45     u.f = av_int2float(f);
  46     return u.i;
  47 #else
  48     uint16_t h;
  49
  50     h = t->basetable[(f >> 23) & 0x1ff] + ((f & 0x007fffff) >> t->shifttable[(f >> 23) & 0x1ff]);
  51
  52     return h;
  53 #endif
  54 }
  55
  56 #endif /* AVUTIL_FLOAT2HALF_H */