mirror of
https://gitee.com/openharmony/third_party_ffmpeg
synced 2024-11-23 03:09:51 +00:00
75 lines
2.3 KiB
C
75 lines
2.3 KiB
C
/*
|
|
* 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
|
|
*/
|
|
|
|
#ifndef AVCODEC_HALF2FLOAT_H
|
|
#define AVCODEC_HALF2FLOAT_H
|
|
|
|
#include <stdint.h>
|
|
|
|
static 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
|
|
}
|
|
|
|
static void half2float_table(uint32_t *mantissatable, uint32_t *exponenttable,
|
|
uint16_t *offsettable)
|
|
{
|
|
mantissatable[0] = 0;
|
|
for (int i = 1; i < 1024; i++)
|
|
mantissatable[i] = convertmantissa(i);
|
|
for (int i = 1024; i < 2048; i++)
|
|
mantissatable[i] = 0x38000000UL + ((i - 1024) << 13UL);
|
|
|
|
exponenttable[0] = 0;
|
|
for (int i = 1; i < 31; i++)
|
|
exponenttable[i] = i << 23;
|
|
for (int i = 33; i < 63; i++)
|
|
exponenttable[i] = 0x80000000UL + ((i - 32) << 23UL);
|
|
exponenttable[31]= 0x47800000UL;
|
|
exponenttable[32]= 0x80000000UL;
|
|
exponenttable[63]= 0xC7800000UL;
|
|
|
|
offsettable[0] = 0;
|
|
for (int i = 1; i < 64; i++)
|
|
offsettable[i] = 1024;
|
|
offsettable[32] = 0;
|
|
}
|
|
|
|
static uint32_t half2float(uint16_t h, uint32_t *mantissatable, uint32_t *exponenttable,
|
|
uint16_t *offsettable)
|
|
{
|
|
uint32_t f;
|
|
|
|
f = mantissatable[offsettable[h >> 10] + (h & 0x3ff)] + exponenttable[h >> 10];
|
|
|
|
return f;
|
|
}
|
|
|
|
#endif /* AVCODEC_HALF2FLOAT_H */
|