3 * MIPS Technologies, Inc., California.
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6 * modification, are permitted provided that the following conditions
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9 * notice, this list of conditions and the following disclaimer.
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14 * contributors may be used to endorse or promote products derived from
15 * this software without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE MIPS TECHNOLOGIES, INC. ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE MIPS TECHNOLOGIES, INC. BE LIABLE
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24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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29 * Author: Nedeljko Babic (nbabic@mips.com)
31 * This file is part of FFmpeg.
33 * FFmpeg is free software; you can redistribute it and/or
34 * modify it under the terms of the GNU Lesser General Public
35 * License as published by the Free Software Foundation; either
36 * version 2.1 of the License, or (at your option) any later version.
38 * FFmpeg is distributed in the hope that it will be useful,
39 * but WITHOUT ANY WARRANTY; without even the implied warranty of
40 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
41 * Lesser General Public License for more details.
43 * You should have received a copy of the GNU Lesser General Public
44 * License along with FFmpeg; if not, write to the Free Software
45 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
48 #ifndef AVUTIL_FIXED_DSP_H
49 #define AVUTIL_FIXED_DSP_H
52 #include "attributes.h"
54 #include "libavcodec/mathops.h"
56 typedef struct AVFixedDSPContext
{
58 * Overlap/add with window function.
59 * Used primarily by MDCT-based audio codecs.
60 * Source and destination vectors must overlap exactly or not at all.
62 * @param dst result vector
63 * constraints: 16-byte aligned
64 * @param src0 first source vector
65 * constraints: 16-byte aligned
66 * @param src1 second source vector
67 * constraints: 16-byte aligned
68 * @param win half-window vector
69 * constraints: 16-byte aligned
70 * @param len length of vector
71 * constraints: multiple of 4
72 * @param bits scaling parameter
75 void (*vector_fmul_window_scaled
)(int16_t *dst
, const int32_t *src0
, const int32_t *src1
, const int32_t *win
, int len
, uint8_t bits
);
78 * Overlap/add with window function.
79 * Used primarily by MDCT-based audio codecs.
80 * Source and destination vectors must overlap exactly or not at all.
82 * @param dst result vector
83 * constraints: 32-byte aligned
84 * @param src0 first source vector
85 * constraints: 16-byte aligned
86 * @param src1 second source vector
87 * constraints: 16-byte aligned
88 * @param win half-window vector
89 * constraints: 16-byte aligned
90 * @param len length of vector
91 * constraints: multiple of 4
93 void (*vector_fmul_window
)(int32_t *dst
, const int32_t *src0
, const int32_t *src1
, const int32_t *win
, int len
);
98 * Allocate and initialize a fixed DSP context.
99 * note: should be freed with a av_free call when no longer needed.
101 * @param strict setting to non-zero avoids using functions which may not be IEEE-754 compliant
103 AVFixedDSPContext
* avpriv_alloc_fixed_dsp(int strict
);
106 * Calculate the square root
108 * @param x input fixed point number
110 * @param bits format of fixed point number (32 - bits).bits
112 * note: input is normalized to (0, 1) fixed point value
115 static av_always_inline
int fixed_sqrt(int x
, int bits
)
117 int retval
, bit_mask
, guess
, square
, i
;
119 int shift1
= 30 - bits
;
120 int shift2
= bits
- 15;
122 if (shift1
> 0) retval
= ff_sqrt(x
<< shift1
);
123 else retval
= ff_sqrt(x
>> -shift1
);
126 retval
= retval
<< shift2
;
127 bit_mask
= (1 << (shift2
- 1));
129 for (i
=0; i
<shift2
; i
++){
130 guess
= retval
+ bit_mask
;
131 accu
= (int64_t)guess
* guess
;
132 square
= (int)((accu
+ bit_mask
) >> bits
);
139 else retval
>>= (-shift2
);
144 #endif /* AVUTIL_FIXED_DSP_H */