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1 | /* |
2 | * Copyright (c) 2012 | |
3 | * MIPS Technologies, Inc., California. | |
4 | * | |
5 | * Redistribution and use in source and binary forms, with or without | |
6 | * modification, are permitted provided that the following conditions | |
7 | * are met: | |
8 | * 1. Redistributions of source code must retain the above copyright | |
9 | * notice, this list of conditions and the following disclaimer. | |
10 | * 2. Redistributions in binary form must reproduce the above copyright | |
11 | * notice, this list of conditions and the following disclaimer in the | |
12 | * documentation and/or other materials provided with the distribution. | |
13 | * 3. Neither the name of the MIPS Technologies, Inc., nor the names of its | |
14 | * contributors may be used to endorse or promote products derived from | |
15 | * this software without specific prior written permission. | |
16 | * | |
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 | |
21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
27 | * SUCH DAMAGE. | |
28 | * | |
29 | * Author: Nedeljko Babic (nbabic@mips.com) | |
30 | * | |
31 | * This file is part of FFmpeg. | |
32 | * | |
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. | |
37 | * | |
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. | |
42 | * | |
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 | |
46 | */ | |
47 | ||
48 | #ifndef AVUTIL_FIXED_DSP_H | |
49 | #define AVUTIL_FIXED_DSP_H | |
50 | ||
51 | #include <stdint.h> | |
52 | #include "attributes.h" | |
53 | #include "common.h" | |
54 | #include "libavcodec/mathops.h" | |
55 | ||
56 | typedef struct AVFixedDSPContext { | |
57 | /** | |
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. | |
61 | * | |
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 | |
73 | * | |
74 | */ | |
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); | |
76 | ||
77 | /** | |
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. | |
81 | * | |
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 | |
92 | */ | |
93 | void (*vector_fmul_window)(int32_t *dst, const int32_t *src0, const int32_t *src1, const int32_t *win, int len); | |
94 | ||
95 | } AVFixedDSPContext; | |
96 | ||
97 | /** | |
98 | * Allocate and initialize a fixed DSP context. | |
99 | * note: should be freed with a av_free call when no longer needed. | |
100 | * | |
101 | * @param strict setting to non-zero avoids using functions which may not be IEEE-754 compliant | |
102 | */ | |
103 | AVFixedDSPContext * avpriv_alloc_fixed_dsp(int strict); | |
104 | ||
105 | /** | |
106 | * Calculate the square root | |
107 | * | |
108 | * @param x input fixed point number | |
109 | * | |
110 | * @param bits format of fixed point number (32 - bits).bits | |
111 | * | |
112 | * note: input is normalized to (0, 1) fixed point value | |
113 | */ | |
114 | ||
115 | static av_always_inline int fixed_sqrt(int x, int bits) | |
116 | { | |
117 | int retval, bit_mask, guess, square, i; | |
118 | int64_t accu; | |
119 | int shift1 = 30 - bits; | |
120 | int shift2 = bits - 15; | |
121 | ||
122 | if (shift1 > 0) retval = ff_sqrt(x << shift1); | |
123 | else retval = ff_sqrt(x >> -shift1); | |
124 | ||
125 | if (shift2 > 0) { | |
126 | retval = retval << shift2; | |
127 | bit_mask = (1 << (shift2 - 1)); | |
128 | ||
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); | |
133 | if (x >= square) | |
134 | retval += bit_mask; | |
135 | bit_mask >>= 1; | |
136 | } | |
137 | ||
138 | } | |
139 | else retval >>= (-shift2); | |
140 | ||
141 | return retval; | |
142 | } | |
143 | ||
144 | #endif /* AVUTIL_FIXED_DSP_H */ |