/* * 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/half2float.h" #if !HAVE_FAST_FLOAT16static uint32_t convertmantissa(uint32_t i){    int32_t m = i << 13; // Zero pad mantissa bits    int32_t e = 0; // Zero exponent     while (!(m & 0x00800000)) { // While not normalized        e -= 0x00800000; // Decrement exponent (1<<23)        m <<= 1; // Shift mantissa    }     m &= ~0x00800000; // Clear leading 1 bit    e +=  0x38800000; // Adjust bias ((127-14)<<23)     return m | e; // Return combined number}#endif void ff_init_half2float_tables(Half2FloatTables *t){#if !HAVE_FAST_FLOAT16    t->mantissatable[0] = 0;    for (int i = 1; i < 1024; i++)        t->mantissatable[i] = convertmantissa(i);    for (int i = 1024; i < 2048; i++)        t->mantissatable[i] = 0x38000000UL + ((i - 1024) << 13UL);    for (int i = 2048; i < 3072; i++)        t->mantissatable[i] = t->mantissatable[i - 1024] | 0x400000UL;    t->mantissatable[2048] = t->mantissatable[1024];     t->exponenttable[0] = 0;    for (int i = 1; i < 31; i++)        t->exponenttable[i] = i << 23;    for (int i = 33; i < 63; i++)        t->exponenttable[i] = 0x80000000UL + ((i - 32) << 23UL);    t->exponenttable[31]= 0x47800000UL;    t->exponenttable[32]= 0x80000000UL;    t->exponenttable[63]= 0xC7800000UL;     t->offsettable[0] = 0;    for (int i = 1; i < 64; i++)        t->offsettable[i] = 1024;    t->offsettable[31] = 2048;    t->offsettable[32] = 0;    t->offsettable[63] = 2048;#endif}