2 * Various fixed-point math operations
4 * Copyright (c) 2008 Vladimir Voroshilov
6 * This file is part of FFmpeg.
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
26 #include "libavutil/avassert.h"
29 #include "celp_math.h"
30 #include "libavutil/common.h"
32 static const uint16_t exp2a
[]=
34 0, 1435, 2901, 4400, 5931, 7496, 9096, 10730,
35 12400, 14106, 15850, 17632, 19454, 21315, 23216, 25160,
36 27146, 29175, 31249, 33368, 35534, 37747, 40009, 42320,
37 44682, 47095, 49562, 52082, 54657, 57289, 59979, 62727,
40 static const uint16_t exp2b
[]=
42 3, 712, 1424, 2134, 2845, 3557, 4270, 4982,
43 5696, 6409, 7124, 7839, 8554, 9270, 9986, 10704,
44 11421, 12138, 12857, 13576, 14295, 15014, 15734, 16455,
45 17176, 17898, 18620, 19343, 20066, 20790, 21514, 22238,
48 int ff_exp2(uint16_t power
)
50 unsigned int result
= exp2a
[power
>>10] + 0x10000;
52 av_assert2(power
<= 0x7fff);
54 result
= (result
<<3) + ((result
*exp2b
[(power
>>5)&31])>>17);
55 return result
+ ((result
*(power
&31)*89)>>22);
59 * Table used to compute log2(x)
61 * tab_log2[i] = (1<<15) * log2(1 + i/32), i=0..32
63 static const uint16_t tab_log2
[33] =
66 0, 1455, 2866, 4236, 5568, 6863, 8124, 9352,
67 10549, 11716, 12855, 13967, 15054, 16117, 17156, 18172,
68 19167, 20142, 21097, 22033, 22951, 23852, 24735, 25603,
69 26455, 27291, 28113, 28922, 29716, 30497, 31266, 32023, 32767,
71 4, 1459, 2870, 4240, 5572, 6867, 8127, 9355,
72 10552, 11719, 12858, 13971, 15057, 16120, 17158, 18175,
73 19170, 20145, 21100, 22036, 22954, 23854, 24738, 25605,
74 26457, 27294, 28116, 28924, 29719, 30500, 31269, 32025, 32769,
78 int ff_log2_q15(uint32_t value
)
84 // Stripping zeros from beginning
85 power_int
= av_log2(value
);
86 value
<<= (31 - power_int
);
88 // b31 is always non-zero now
89 frac_x0
= (value
& 0x7c000000) >> 26; // b26-b31 and [32..63] -> [0..31]
90 frac_dx
= (value
& 0x03fff800) >> 11;
92 value
= tab_log2
[frac_x0
];
93 value
+= (frac_dx
* (tab_log2
[frac_x0
+1] - tab_log2
[frac_x0
])) >> 15;
95 return (power_int
<< 15) + value
;
98 int64_t ff_dot_product(const int16_t *a
, const int16_t *b
, int length
)
103 for (i
= 0; i
< length
; i
++)
104 sum
+= MUL16(a
[i
], b
[i
]);
109 float ff_dot_productf(const float* a
, const float* b
, int length
)
114 for(i
=0; i
<length
; i
++)
120 void ff_celp_math_init(CELPMContext
*c
)
122 c
->dot_productf
= ff_dot_productf
;
125 ff_celp_math_init_mips(c
);