1 /*
2 * http://www.kurims.kyoto-u.ac.jp/~ooura/fft.html
3 * Copyright Takuya OOURA, 1996-2001
4 *
5 * You may use, copy, modify and distribute this code for any purpose (include
6 * commercial use) and without fee. Please refer to this package when you modify
7 * this code.
8 *
9 * Changes by the WebRTC authors:
10 * - Trivial type modifications.
11 * - Minimal code subset to do rdft of length 128.
12 * - Optimizations because of known length.
13 *
14 * All changes are covered by the WebRTC license and IP grant:
15 * Use of this source code is governed by a BSD-style license
16 * that can be found in the LICENSE file in the root of the source
17 * tree. An additional intellectual property rights grant can be found
18 * in the file PATENTS. All contributing project authors may
19 * be found in the AUTHORS file in the root of the source tree.
20 */
21
22 #include "webrtc/modules/audio_processing/aec/aec_rdft.h"
23
24 #include <math.h>
25
26 #include "webrtc/system_wrappers/include/cpu_features_wrapper.h"
27 #include "webrtc/typedefs.h"
28
29 // These tables used to be computed at run-time. For example, refer to:
30 // https://code.google.com/p/webrtc/source/browse/trunk/webrtc/modules/audio_processing/aec/aec_rdft.c?r=6564
31 // to see the initialization code.
32 const float rdft_w[64] = {
33 1.0000000000f, 0.0000000000f, 0.7071067691f, 0.7071067691f,
34 0.9238795638f, 0.3826834559f, 0.3826834559f, 0.9238795638f,
35 0.9807852507f, 0.1950903237f, 0.5555702448f, 0.8314695954f,
36 0.8314695954f, 0.5555702448f, 0.1950903237f, 0.9807852507f,
37 0.9951847196f, 0.0980171412f, 0.6343933344f, 0.7730104327f,
38 0.8819212914f, 0.4713967443f, 0.2902846634f, 0.9569403529f,
39 0.9569403529f, 0.2902846634f, 0.4713967443f, 0.8819212914f,
40 0.7730104327f, 0.6343933344f, 0.0980171412f, 0.9951847196f,
41 0.7071067691f, 0.4993977249f, 0.4975923598f, 0.4945882559f,
42 0.4903926253f, 0.4850156307f, 0.4784701765f, 0.4707720280f,
43 0.4619397819f, 0.4519946277f, 0.4409606457f, 0.4288643003f,
44 0.4157347977f, 0.4016037583f, 0.3865052164f, 0.3704755902f,
45 0.3535533845f, 0.3357794881f, 0.3171966672f, 0.2978496552f,
46 0.2777851224f, 0.2570513785f, 0.2356983721f, 0.2137775421f,
47 0.1913417280f, 0.1684449315f, 0.1451423317f, 0.1214900985f,
48 0.0975451618f, 0.0733652338f, 0.0490085706f, 0.0245338380f,
49 };
50 const float rdft_wk3ri_first[16] = {
51 1.000000000f, 0.000000000f, 0.382683456f, 0.923879564f,
52 0.831469536f, 0.555570245f, -0.195090353f, 0.980785251f,
53 0.956940353f, 0.290284693f, 0.098017156f, 0.995184720f,
54 0.634393334f, 0.773010492f, -0.471396863f, 0.881921172f,
55 };
56 const float rdft_wk3ri_second[16] = {
57 -0.707106769f, 0.707106769f, -0.923879564f, -0.382683456f,
58 -0.980785251f, 0.195090353f, -0.555570245f, -0.831469536f,
59 -0.881921172f, 0.471396863f, -0.773010492f, -0.634393334f,
60 -0.995184720f, -0.098017156f, -0.290284693f, -0.956940353f,
61 };
62 ALIGN16_BEG const float ALIGN16_END rdft_wk1r[32] = {
63 1.000000000f, 1.000000000f, 0.707106769f, 0.707106769f,
64 0.923879564f, 0.923879564f, 0.382683456f, 0.382683456f,
65 0.980785251f, 0.980785251f, 0.555570245f, 0.555570245f,
66 0.831469595f, 0.831469595f, 0.195090324f, 0.195090324f,
67 0.995184720f, 0.995184720f, 0.634393334f, 0.634393334f,
68 0.881921291f, 0.881921291f, 0.290284663f, 0.290284663f,
69 0.956940353f, 0.956940353f, 0.471396744f, 0.471396744f,
70 0.773010433f, 0.773010433f, 0.098017141f, 0.098017141f,
71 };
72 ALIGN16_BEG const float ALIGN16_END rdft_wk2r[32] = {
73 1.000000000f, 1.000000000f, -0.000000000f, -0.000000000f,
74 0.707106769f, 0.707106769f, -0.707106769f, -0.707106769f,
75 0.923879564f, 0.923879564f, -0.382683456f, -0.382683456f,
76 0.382683456f, 0.382683456f, -0.923879564f, -0.923879564f,
77 0.980785251f, 0.980785251f, -0.195090324f, -0.195090324f,
78 0.555570245f, 0.555570245f, -0.831469595f, -0.831469595f,
79 0.831469595f, 0.831469595f, -0.555570245f, -0.555570245f,
80 0.195090324f, 0.195090324f, -0.980785251f, -0.980785251f,
81 };
82 ALIGN16_BEG const float ALIGN16_END rdft_wk3r[32] = {
83 1.000000000f, 1.000000000f, -0.707106769f, -0.707106769f,
84 0.382683456f, 0.382683456f, -0.923879564f, -0.923879564f,
85 0.831469536f, 0.831469536f, -0.980785251f, -0.980785251f,
86 -0.195090353f, -0.195090353f, -0.555570245f, -0.555570245f,
87 0.956940353f, 0.956940353f, -0.881921172f, -0.881921172f,
88 0.098017156f, 0.098017156f, -0.773010492f, -0.773010492f,
89 0.634393334f, 0.634393334f, -0.995184720f, -0.995184720f,
90 -0.471396863f, -0.471396863f, -0.290284693f, -0.290284693f,
91 };
92 ALIGN16_BEG const float ALIGN16_END rdft_wk1i[32] = {
93 -0.000000000f, 0.000000000f, -0.707106769f, 0.707106769f,
94 -0.382683456f, 0.382683456f, -0.923879564f, 0.923879564f,
95 -0.195090324f, 0.195090324f, -0.831469595f, 0.831469595f,
96 -0.555570245f, 0.555570245f, -0.980785251f, 0.980785251f,
97 -0.098017141f, 0.098017141f, -0.773010433f, 0.773010433f,
98 -0.471396744f, 0.471396744f, -0.956940353f, 0.956940353f,
99 -0.290284663f, 0.290284663f, -0.881921291f, 0.881921291f,
100 -0.634393334f, 0.634393334f, -0.995184720f, 0.995184720f,
101 };
102 ALIGN16_BEG const float ALIGN16_END rdft_wk2i[32] = {
103 -0.000000000f, 0.000000000f, -1.000000000f, 1.000000000f,
104 -0.707106769f, 0.707106769f, -0.707106769f, 0.707106769f,
105 -0.382683456f, 0.382683456f, -0.923879564f, 0.923879564f,
106 -0.923879564f, 0.923879564f, -0.382683456f, 0.382683456f,
107 -0.195090324f, 0.195090324f, -0.980785251f, 0.980785251f,
108 -0.831469595f, 0.831469595f, -0.555570245f, 0.555570245f,
109 -0.555570245f, 0.555570245f, -0.831469595f, 0.831469595f,
110 -0.980785251f, 0.980785251f, -0.195090324f, 0.195090324f,
111 };
112 ALIGN16_BEG const float ALIGN16_END rdft_wk3i[32] = {
113 -0.000000000f, 0.000000000f, -0.707106769f, 0.707106769f,
114 -0.923879564f, 0.923879564f, 0.382683456f, -0.382683456f,
115 -0.555570245f, 0.555570245f, -0.195090353f, 0.195090353f,
116 -0.980785251f, 0.980785251f, 0.831469536f, -0.831469536f,
117 -0.290284693f, 0.290284693f, -0.471396863f, 0.471396863f,
118 -0.995184720f, 0.995184720f, 0.634393334f, -0.634393334f,
119 -0.773010492f, 0.773010492f, 0.098017156f, -0.098017156f,
120 -0.881921172f, 0.881921172f, 0.956940353f, -0.956940353f,
121 };
122 ALIGN16_BEG const float ALIGN16_END cftmdl_wk1r[4] = {
123 0.707106769f, 0.707106769f, 0.707106769f, -0.707106769f,
124 };
125
bitrv2_128_C(float * a)126 static void bitrv2_128_C(float* a) {
127 /*
128 Following things have been attempted but are no faster:
129 (a) Storing the swap indexes in a LUT (index calculations are done
130 for 'free' while waiting on memory/L1).
131 (b) Consolidate the load/store of two consecutive floats by a 64 bit
132 integer (execution is memory/L1 bound).
133 (c) Do a mix of floats and 64 bit integer to maximize register
134 utilization (execution is memory/L1 bound).
135 (d) Replacing ip[i] by ((k<<31)>>25) + ((k >> 1)<<5).
136 (e) Hard-coding of the offsets to completely eliminates index
137 calculations.
138 */
139
140 unsigned int j, j1, k, k1;
141 float xr, xi, yr, yi;
142
143 static const int ip[4] = {0, 64, 32, 96};
144 for (k = 0; k < 4; k++) {
145 for (j = 0; j < k; j++) {
146 j1 = 2 * j + ip[k];
147 k1 = 2 * k + ip[j];
148 xr = a[j1 + 0];
149 xi = a[j1 + 1];
150 yr = a[k1 + 0];
151 yi = a[k1 + 1];
152 a[j1 + 0] = yr;
153 a[j1 + 1] = yi;
154 a[k1 + 0] = xr;
155 a[k1 + 1] = xi;
156 j1 += 8;
157 k1 += 16;
158 xr = a[j1 + 0];
159 xi = a[j1 + 1];
160 yr = a[k1 + 0];
161 yi = a[k1 + 1];
162 a[j1 + 0] = yr;
163 a[j1 + 1] = yi;
164 a[k1 + 0] = xr;
165 a[k1 + 1] = xi;
166 j1 += 8;
167 k1 -= 8;
168 xr = a[j1 + 0];
169 xi = a[j1 + 1];
170 yr = a[k1 + 0];
171 yi = a[k1 + 1];
172 a[j1 + 0] = yr;
173 a[j1 + 1] = yi;
174 a[k1 + 0] = xr;
175 a[k1 + 1] = xi;
176 j1 += 8;
177 k1 += 16;
178 xr = a[j1 + 0];
179 xi = a[j1 + 1];
180 yr = a[k1 + 0];
181 yi = a[k1 + 1];
182 a[j1 + 0] = yr;
183 a[j1 + 1] = yi;
184 a[k1 + 0] = xr;
185 a[k1 + 1] = xi;
186 }
187 j1 = 2 * k + 8 + ip[k];
188 k1 = j1 + 8;
189 xr = a[j1 + 0];
190 xi = a[j1 + 1];
191 yr = a[k1 + 0];
192 yi = a[k1 + 1];
193 a[j1 + 0] = yr;
194 a[j1 + 1] = yi;
195 a[k1 + 0] = xr;
196 a[k1 + 1] = xi;
197 }
198 }
199
cft1st_128_C(float * a)200 static void cft1st_128_C(float* a) {
201 const int n = 128;
202 int j, k1, k2;
203 float wk1r, wk1i, wk2r, wk2i, wk3r, wk3i;
204 float x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i;
205
206 // The processing of the first set of elements was simplified in C to avoid
207 // some operations (multiplication by zero or one, addition of two elements
208 // multiplied by the same weight, ...).
209 x0r = a[0] + a[2];
210 x0i = a[1] + a[3];
211 x1r = a[0] - a[2];
212 x1i = a[1] - a[3];
213 x2r = a[4] + a[6];
214 x2i = a[5] + a[7];
215 x3r = a[4] - a[6];
216 x3i = a[5] - a[7];
217 a[0] = x0r + x2r;
218 a[1] = x0i + x2i;
219 a[4] = x0r - x2r;
220 a[5] = x0i - x2i;
221 a[2] = x1r - x3i;
222 a[3] = x1i + x3r;
223 a[6] = x1r + x3i;
224 a[7] = x1i - x3r;
225 wk1r = rdft_w[2];
226 x0r = a[8] + a[10];
227 x0i = a[9] + a[11];
228 x1r = a[8] - a[10];
229 x1i = a[9] - a[11];
230 x2r = a[12] + a[14];
231 x2i = a[13] + a[15];
232 x3r = a[12] - a[14];
233 x3i = a[13] - a[15];
234 a[8] = x0r + x2r;
235 a[9] = x0i + x2i;
236 a[12] = x2i - x0i;
237 a[13] = x0r - x2r;
238 x0r = x1r - x3i;
239 x0i = x1i + x3r;
240 a[10] = wk1r * (x0r - x0i);
241 a[11] = wk1r * (x0r + x0i);
242 x0r = x3i + x1r;
243 x0i = x3r - x1i;
244 a[14] = wk1r * (x0i - x0r);
245 a[15] = wk1r * (x0i + x0r);
246 k1 = 0;
247 for (j = 16; j < n; j += 16) {
248 k1 += 2;
249 k2 = 2 * k1;
250 wk2r = rdft_w[k1 + 0];
251 wk2i = rdft_w[k1 + 1];
252 wk1r = rdft_w[k2 + 0];
253 wk1i = rdft_w[k2 + 1];
254 wk3r = rdft_wk3ri_first[k1 + 0];
255 wk3i = rdft_wk3ri_first[k1 + 1];
256 x0r = a[j + 0] + a[j + 2];
257 x0i = a[j + 1] + a[j + 3];
258 x1r = a[j + 0] - a[j + 2];
259 x1i = a[j + 1] - a[j + 3];
260 x2r = a[j + 4] + a[j + 6];
261 x2i = a[j + 5] + a[j + 7];
262 x3r = a[j + 4] - a[j + 6];
263 x3i = a[j + 5] - a[j + 7];
264 a[j + 0] = x0r + x2r;
265 a[j + 1] = x0i + x2i;
266 x0r -= x2r;
267 x0i -= x2i;
268 a[j + 4] = wk2r * x0r - wk2i * x0i;
269 a[j + 5] = wk2r * x0i + wk2i * x0r;
270 x0r = x1r - x3i;
271 x0i = x1i + x3r;
272 a[j + 2] = wk1r * x0r - wk1i * x0i;
273 a[j + 3] = wk1r * x0i + wk1i * x0r;
274 x0r = x1r + x3i;
275 x0i = x1i - x3r;
276 a[j + 6] = wk3r * x0r - wk3i * x0i;
277 a[j + 7] = wk3r * x0i + wk3i * x0r;
278 wk1r = rdft_w[k2 + 2];
279 wk1i = rdft_w[k2 + 3];
280 wk3r = rdft_wk3ri_second[k1 + 0];
281 wk3i = rdft_wk3ri_second[k1 + 1];
282 x0r = a[j + 8] + a[j + 10];
283 x0i = a[j + 9] + a[j + 11];
284 x1r = a[j + 8] - a[j + 10];
285 x1i = a[j + 9] - a[j + 11];
286 x2r = a[j + 12] + a[j + 14];
287 x2i = a[j + 13] + a[j + 15];
288 x3r = a[j + 12] - a[j + 14];
289 x3i = a[j + 13] - a[j + 15];
290 a[j + 8] = x0r + x2r;
291 a[j + 9] = x0i + x2i;
292 x0r -= x2r;
293 x0i -= x2i;
294 a[j + 12] = -wk2i * x0r - wk2r * x0i;
295 a[j + 13] = -wk2i * x0i + wk2r * x0r;
296 x0r = x1r - x3i;
297 x0i = x1i + x3r;
298 a[j + 10] = wk1r * x0r - wk1i * x0i;
299 a[j + 11] = wk1r * x0i + wk1i * x0r;
300 x0r = x1r + x3i;
301 x0i = x1i - x3r;
302 a[j + 14] = wk3r * x0r - wk3i * x0i;
303 a[j + 15] = wk3r * x0i + wk3i * x0r;
304 }
305 }
306
cftmdl_128_C(float * a)307 static void cftmdl_128_C(float* a) {
308 const int l = 8;
309 const int n = 128;
310 const int m = 32;
311 int j0, j1, j2, j3, k, k1, k2, m2;
312 float wk1r, wk1i, wk2r, wk2i, wk3r, wk3i;
313 float x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i;
314
315 for (j0 = 0; j0 < l; j0 += 2) {
316 j1 = j0 + 8;
317 j2 = j0 + 16;
318 j3 = j0 + 24;
319 x0r = a[j0 + 0] + a[j1 + 0];
320 x0i = a[j0 + 1] + a[j1 + 1];
321 x1r = a[j0 + 0] - a[j1 + 0];
322 x1i = a[j0 + 1] - a[j1 + 1];
323 x2r = a[j2 + 0] + a[j3 + 0];
324 x2i = a[j2 + 1] + a[j3 + 1];
325 x3r = a[j2 + 0] - a[j3 + 0];
326 x3i = a[j2 + 1] - a[j3 + 1];
327 a[j0 + 0] = x0r + x2r;
328 a[j0 + 1] = x0i + x2i;
329 a[j2 + 0] = x0r - x2r;
330 a[j2 + 1] = x0i - x2i;
331 a[j1 + 0] = x1r - x3i;
332 a[j1 + 1] = x1i + x3r;
333 a[j3 + 0] = x1r + x3i;
334 a[j3 + 1] = x1i - x3r;
335 }
336 wk1r = rdft_w[2];
337 for (j0 = m; j0 < l + m; j0 += 2) {
338 j1 = j0 + 8;
339 j2 = j0 + 16;
340 j3 = j0 + 24;
341 x0r = a[j0 + 0] + a[j1 + 0];
342 x0i = a[j0 + 1] + a[j1 + 1];
343 x1r = a[j0 + 0] - a[j1 + 0];
344 x1i = a[j0 + 1] - a[j1 + 1];
345 x2r = a[j2 + 0] + a[j3 + 0];
346 x2i = a[j2 + 1] + a[j3 + 1];
347 x3r = a[j2 + 0] - a[j3 + 0];
348 x3i = a[j2 + 1] - a[j3 + 1];
349 a[j0 + 0] = x0r + x2r;
350 a[j0 + 1] = x0i + x2i;
351 a[j2 + 0] = x2i - x0i;
352 a[j2 + 1] = x0r - x2r;
353 x0r = x1r - x3i;
354 x0i = x1i + x3r;
355 a[j1 + 0] = wk1r * (x0r - x0i);
356 a[j1 + 1] = wk1r * (x0r + x0i);
357 x0r = x3i + x1r;
358 x0i = x3r - x1i;
359 a[j3 + 0] = wk1r * (x0i - x0r);
360 a[j3 + 1] = wk1r * (x0i + x0r);
361 }
362 k1 = 0;
363 m2 = 2 * m;
364 for (k = m2; k < n; k += m2) {
365 k1 += 2;
366 k2 = 2 * k1;
367 wk2r = rdft_w[k1 + 0];
368 wk2i = rdft_w[k1 + 1];
369 wk1r = rdft_w[k2 + 0];
370 wk1i = rdft_w[k2 + 1];
371 wk3r = rdft_wk3ri_first[k1 + 0];
372 wk3i = rdft_wk3ri_first[k1 + 1];
373 for (j0 = k; j0 < l + k; j0 += 2) {
374 j1 = j0 + 8;
375 j2 = j0 + 16;
376 j3 = j0 + 24;
377 x0r = a[j0 + 0] + a[j1 + 0];
378 x0i = a[j0 + 1] + a[j1 + 1];
379 x1r = a[j0 + 0] - a[j1 + 0];
380 x1i = a[j0 + 1] - a[j1 + 1];
381 x2r = a[j2 + 0] + a[j3 + 0];
382 x2i = a[j2 + 1] + a[j3 + 1];
383 x3r = a[j2 + 0] - a[j3 + 0];
384 x3i = a[j2 + 1] - a[j3 + 1];
385 a[j0 + 0] = x0r + x2r;
386 a[j0 + 1] = x0i + x2i;
387 x0r -= x2r;
388 x0i -= x2i;
389 a[j2 + 0] = wk2r * x0r - wk2i * x0i;
390 a[j2 + 1] = wk2r * x0i + wk2i * x0r;
391 x0r = x1r - x3i;
392 x0i = x1i + x3r;
393 a[j1 + 0] = wk1r * x0r - wk1i * x0i;
394 a[j1 + 1] = wk1r * x0i + wk1i * x0r;
395 x0r = x1r + x3i;
396 x0i = x1i - x3r;
397 a[j3 + 0] = wk3r * x0r - wk3i * x0i;
398 a[j3 + 1] = wk3r * x0i + wk3i * x0r;
399 }
400 wk1r = rdft_w[k2 + 2];
401 wk1i = rdft_w[k2 + 3];
402 wk3r = rdft_wk3ri_second[k1 + 0];
403 wk3i = rdft_wk3ri_second[k1 + 1];
404 for (j0 = k + m; j0 < l + (k + m); j0 += 2) {
405 j1 = j0 + 8;
406 j2 = j0 + 16;
407 j3 = j0 + 24;
408 x0r = a[j0 + 0] + a[j1 + 0];
409 x0i = a[j0 + 1] + a[j1 + 1];
410 x1r = a[j0 + 0] - a[j1 + 0];
411 x1i = a[j0 + 1] - a[j1 + 1];
412 x2r = a[j2 + 0] + a[j3 + 0];
413 x2i = a[j2 + 1] + a[j3 + 1];
414 x3r = a[j2 + 0] - a[j3 + 0];
415 x3i = a[j2 + 1] - a[j3 + 1];
416 a[j0 + 0] = x0r + x2r;
417 a[j0 + 1] = x0i + x2i;
418 x0r -= x2r;
419 x0i -= x2i;
420 a[j2 + 0] = -wk2i * x0r - wk2r * x0i;
421 a[j2 + 1] = -wk2i * x0i + wk2r * x0r;
422 x0r = x1r - x3i;
423 x0i = x1i + x3r;
424 a[j1 + 0] = wk1r * x0r - wk1i * x0i;
425 a[j1 + 1] = wk1r * x0i + wk1i * x0r;
426 x0r = x1r + x3i;
427 x0i = x1i - x3r;
428 a[j3 + 0] = wk3r * x0r - wk3i * x0i;
429 a[j3 + 1] = wk3r * x0i + wk3i * x0r;
430 }
431 }
432 }
433
cftfsub_128_C(float * a)434 static void cftfsub_128_C(float* a) {
435 int j, j1, j2, j3, l;
436 float x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i;
437
438 cft1st_128(a);
439 cftmdl_128(a);
440 l = 32;
441 for (j = 0; j < l; j += 2) {
442 j1 = j + l;
443 j2 = j1 + l;
444 j3 = j2 + l;
445 x0r = a[j] + a[j1];
446 x0i = a[j + 1] + a[j1 + 1];
447 x1r = a[j] - a[j1];
448 x1i = a[j + 1] - a[j1 + 1];
449 x2r = a[j2] + a[j3];
450 x2i = a[j2 + 1] + a[j3 + 1];
451 x3r = a[j2] - a[j3];
452 x3i = a[j2 + 1] - a[j3 + 1];
453 a[j] = x0r + x2r;
454 a[j + 1] = x0i + x2i;
455 a[j2] = x0r - x2r;
456 a[j2 + 1] = x0i - x2i;
457 a[j1] = x1r - x3i;
458 a[j1 + 1] = x1i + x3r;
459 a[j3] = x1r + x3i;
460 a[j3 + 1] = x1i - x3r;
461 }
462 }
463
cftbsub_128_C(float * a)464 static void cftbsub_128_C(float* a) {
465 int j, j1, j2, j3, l;
466 float x0r, x0i, x1r, x1i, x2r, x2i, x3r, x3i;
467
468 cft1st_128(a);
469 cftmdl_128(a);
470 l = 32;
471
472 for (j = 0; j < l; j += 2) {
473 j1 = j + l;
474 j2 = j1 + l;
475 j3 = j2 + l;
476 x0r = a[j] + a[j1];
477 x0i = -a[j + 1] - a[j1 + 1];
478 x1r = a[j] - a[j1];
479 x1i = -a[j + 1] + a[j1 + 1];
480 x2r = a[j2] + a[j3];
481 x2i = a[j2 + 1] + a[j3 + 1];
482 x3r = a[j2] - a[j3];
483 x3i = a[j2 + 1] - a[j3 + 1];
484 a[j] = x0r + x2r;
485 a[j + 1] = x0i - x2i;
486 a[j2] = x0r - x2r;
487 a[j2 + 1] = x0i + x2i;
488 a[j1] = x1r - x3i;
489 a[j1 + 1] = x1i - x3r;
490 a[j3] = x1r + x3i;
491 a[j3 + 1] = x1i + x3r;
492 }
493 }
494
rftfsub_128_C(float * a)495 static void rftfsub_128_C(float* a) {
496 const float* c = rdft_w + 32;
497 int j1, j2, k1, k2;
498 float wkr, wki, xr, xi, yr, yi;
499
500 for (j1 = 1, j2 = 2; j2 < 64; j1 += 1, j2 += 2) {
501 k2 = 128 - j2;
502 k1 = 32 - j1;
503 wkr = 0.5f - c[k1];
504 wki = c[j1];
505 xr = a[j2 + 0] - a[k2 + 0];
506 xi = a[j2 + 1] + a[k2 + 1];
507 yr = wkr * xr - wki * xi;
508 yi = wkr * xi + wki * xr;
509 a[j2 + 0] -= yr;
510 a[j2 + 1] -= yi;
511 a[k2 + 0] += yr;
512 a[k2 + 1] -= yi;
513 }
514 }
515
rftbsub_128_C(float * a)516 static void rftbsub_128_C(float* a) {
517 const float* c = rdft_w + 32;
518 int j1, j2, k1, k2;
519 float wkr, wki, xr, xi, yr, yi;
520
521 a[1] = -a[1];
522 for (j1 = 1, j2 = 2; j2 < 64; j1 += 1, j2 += 2) {
523 k2 = 128 - j2;
524 k1 = 32 - j1;
525 wkr = 0.5f - c[k1];
526 wki = c[j1];
527 xr = a[j2 + 0] - a[k2 + 0];
528 xi = a[j2 + 1] + a[k2 + 1];
529 yr = wkr * xr + wki * xi;
530 yi = wkr * xi - wki * xr;
531 a[j2 + 0] = a[j2 + 0] - yr;
532 a[j2 + 1] = yi - a[j2 + 1];
533 a[k2 + 0] = yr + a[k2 + 0];
534 a[k2 + 1] = yi - a[k2 + 1];
535 }
536 a[65] = -a[65];
537 }
538
aec_rdft_forward_128(float * a)539 void aec_rdft_forward_128(float* a) {
540 float xi;
541 bitrv2_128(a);
542 cftfsub_128(a);
543 rftfsub_128(a);
544 xi = a[0] - a[1];
545 a[0] += a[1];
546 a[1] = xi;
547 }
548
aec_rdft_inverse_128(float * a)549 void aec_rdft_inverse_128(float* a) {
550 a[1] = 0.5f * (a[0] - a[1]);
551 a[0] -= a[1];
552 rftbsub_128(a);
553 bitrv2_128(a);
554 cftbsub_128(a);
555 }
556
557 // code path selection
558 RftSub128 cft1st_128;
559 RftSub128 cftmdl_128;
560 RftSub128 rftfsub_128;
561 RftSub128 rftbsub_128;
562 RftSub128 cftfsub_128;
563 RftSub128 cftbsub_128;
564 RftSub128 bitrv2_128;
565
aec_rdft_init(void)566 void aec_rdft_init(void) {
567 cft1st_128 = cft1st_128_C;
568 cftmdl_128 = cftmdl_128_C;
569 rftfsub_128 = rftfsub_128_C;
570 rftbsub_128 = rftbsub_128_C;
571 cftfsub_128 = cftfsub_128_C;
572 cftbsub_128 = cftbsub_128_C;
573 bitrv2_128 = bitrv2_128_C;
574 #if defined(WEBRTC_ARCH_X86_FAMILY)
575 if (WebRtc_GetCPUInfo(kSSE2)) {
576 aec_rdft_init_sse2();
577 }
578 #endif
579 #if defined(MIPS_FPU_LE)
580 aec_rdft_init_mips();
581 #endif
582 #if defined(WEBRTC_HAS_NEON)
583 aec_rdft_init_neon();
584 #elif defined(WEBRTC_DETECT_NEON)
585 if ((WebRtc_GetCPUFeaturesARM() & kCPUFeatureNEON) != 0) {
586 aec_rdft_init_neon();
587 }
588 #endif
589 }
590