/*

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include "libavutil/float2half.h"

void ff_init_float2half_tables(Float2HalfTables *t)

{

#if !HAVE_FAST_FLOAT16

    for (int i = 0; i < 256; i++) {

        int e = i - 127;

        if (e < -24) { // Very small numbers map to zero

            t->basetable[i|0x000]  = 0x0000;

            t->basetable[i|0x100]  = 0x8000;

            t->shifttable[i|0x000] = 24;

            t->shifttable[i|0x100] = 24;

        } else if (e < -14) { // Small numbers map to denorms

            t->basetable[i|0x000] = (0x0400>>(-e-14));

            t->basetable[i|0x100] = (0x0400>>(-e-14)) | 0x8000;

            t->shifttable[i|0x000] = -e-1;

            t->shifttable[i|0x100] = -e-1;

        } else if (e <= 15) { // Normal numbers just lose precision

            t->basetable[i|0x000] = ((e + 15) << 10);

            t->basetable[i|0x100] = ((e + 15) << 10) | 0x8000;

            t->shifttable[i|0x000] = 13;

            t->shifttable[i|0x100] = 13;

        } else if (e < 128) { // Large numbers map to Infinity

            t->basetable[i|0x000]  = 0x7C00;

            t->basetable[i|0x100]  = 0xFC00;

            t->shifttable[i|0x000] = 24;

            t->shifttable[i|0x100] = 24;

        } else { // Infinity and NaN's stay Infinity and NaN's

            t->basetable[i|0x000]  = 0x7C00;

            t->basetable[i|0x100]  = 0xFC00;

            t->shifttable[i|0x000] = 13;

            t->shifttable[i|0x100] = 13;

        }

    }

#endif

}