| 1 | /* |
| 2 | * FFT/IFFT transforms |
| 3 | * Copyright (c) 2008 Loren Merritt |
| 4 | * Copyright (c) 2002 Fabrice Bellard |
| 5 | * Partly based on libdjbfft by D. J. Bernstein |
| 6 | * |
| 7 | * This file is part of FFmpeg. |
| 8 | * |
| 9 | * FFmpeg is free software; you can redistribute it and/or |
| 10 | * modify it under the terms of the GNU Lesser General Public |
| 11 | * License as published by the Free Software Foundation; either |
| 12 | * version 2.1 of the License, or (at your option) any later version. |
| 13 | * |
| 14 | * FFmpeg is distributed in the hope that it will be useful, |
| 15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 17 | * Lesser General Public License for more details. |
| 18 | * |
| 19 | * You should have received a copy of the GNU Lesser General Public |
| 20 | * License along with FFmpeg; if not, write to the Free Software |
| 21 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 22 | */ |
| 23 | |
| 24 | /** |
| 25 | * @file |
| 26 | * FFT/IFFT transforms. |
| 27 | */ |
| 28 | |
| 29 | #include <stdlib.h> |
| 30 | #include <string.h> |
| 31 | #include "libavutil/mathematics.h" |
| 32 | #include "fft.h" |
| 33 | #include "fft-internal.h" |
| 34 | |
| 35 | #if FFT_FIXED_32 |
| 36 | #include "fft_table.h" |
| 37 | #else /* FFT_FIXED_32 */ |
| 38 | |
| 39 | /* cos(2*pi*x/n) for 0<=x<=n/4, followed by its reverse */ |
| 40 | #if !CONFIG_HARDCODED_TABLES |
| 41 | COSTABLE(16); |
| 42 | COSTABLE(32); |
| 43 | COSTABLE(64); |
| 44 | COSTABLE(128); |
| 45 | COSTABLE(256); |
| 46 | COSTABLE(512); |
| 47 | COSTABLE(1024); |
| 48 | COSTABLE(2048); |
| 49 | COSTABLE(4096); |
| 50 | COSTABLE(8192); |
| 51 | COSTABLE(16384); |
| 52 | COSTABLE(32768); |
| 53 | COSTABLE(65536); |
| 54 | #endif |
| 55 | COSTABLE_CONST FFTSample * const FFT_NAME(ff_cos_tabs)[] = { |
| 56 | NULL, NULL, NULL, NULL, |
| 57 | FFT_NAME(ff_cos_16), |
| 58 | FFT_NAME(ff_cos_32), |
| 59 | FFT_NAME(ff_cos_64), |
| 60 | FFT_NAME(ff_cos_128), |
| 61 | FFT_NAME(ff_cos_256), |
| 62 | FFT_NAME(ff_cos_512), |
| 63 | FFT_NAME(ff_cos_1024), |
| 64 | FFT_NAME(ff_cos_2048), |
| 65 | FFT_NAME(ff_cos_4096), |
| 66 | FFT_NAME(ff_cos_8192), |
| 67 | FFT_NAME(ff_cos_16384), |
| 68 | FFT_NAME(ff_cos_32768), |
| 69 | FFT_NAME(ff_cos_65536), |
| 70 | }; |
| 71 | |
| 72 | #endif /* FFT_FIXED_32 */ |
| 73 | |
| 74 | static void fft_permute_c(FFTContext *s, FFTComplex *z); |
| 75 | static void fft_calc_c(FFTContext *s, FFTComplex *z); |
| 76 | |
| 77 | static int split_radix_permutation(int i, int n, int inverse) |
| 78 | { |
| 79 | int m; |
| 80 | if(n <= 2) return i&1; |
| 81 | m = n >> 1; |
| 82 | if(!(i&m)) return split_radix_permutation(i, m, inverse)*2; |
| 83 | m >>= 1; |
| 84 | if(inverse == !(i&m)) return split_radix_permutation(i, m, inverse)*4 + 1; |
| 85 | else return split_radix_permutation(i, m, inverse)*4 - 1; |
| 86 | } |
| 87 | |
| 88 | av_cold void ff_init_ff_cos_tabs(int index) |
| 89 | { |
| 90 | #if (!CONFIG_HARDCODED_TABLES) && (!FFT_FIXED_32) |
| 91 | int i; |
| 92 | int m = 1<<index; |
| 93 | double freq = 2*M_PI/m; |
| 94 | FFTSample *tab = FFT_NAME(ff_cos_tabs)[index]; |
| 95 | for(i=0; i<=m/4; i++) |
| 96 | tab[i] = FIX15(cos(i*freq)); |
| 97 | for(i=1; i<m/4; i++) |
| 98 | tab[m/2-i] = tab[i]; |
| 99 | #endif |
| 100 | } |
| 101 | |
| 102 | static const int avx_tab[] = { |
| 103 | 0, 4, 1, 5, 8, 12, 9, 13, 2, 6, 3, 7, 10, 14, 11, 15 |
| 104 | }; |
| 105 | |
| 106 | static int is_second_half_of_fft32(int i, int n) |
| 107 | { |
| 108 | if (n <= 32) |
| 109 | return i >= 16; |
| 110 | else if (i < n/2) |
| 111 | return is_second_half_of_fft32(i, n/2); |
| 112 | else if (i < 3*n/4) |
| 113 | return is_second_half_of_fft32(i - n/2, n/4); |
| 114 | else |
| 115 | return is_second_half_of_fft32(i - 3*n/4, n/4); |
| 116 | } |
| 117 | |
| 118 | static av_cold void fft_perm_avx(FFTContext *s) |
| 119 | { |
| 120 | int i; |
| 121 | int n = 1 << s->nbits; |
| 122 | |
| 123 | for (i = 0; i < n; i += 16) { |
| 124 | int k; |
| 125 | if (is_second_half_of_fft32(i, n)) { |
| 126 | for (k = 0; k < 16; k++) |
| 127 | s->revtab[-split_radix_permutation(i + k, n, s->inverse) & (n - 1)] = |
| 128 | i + avx_tab[k]; |
| 129 | |
| 130 | } else { |
| 131 | for (k = 0; k < 16; k++) { |
| 132 | int j = i + k; |
| 133 | j = (j & ~7) | ((j >> 1) & 3) | ((j << 2) & 4); |
| 134 | s->revtab[-split_radix_permutation(i + k, n, s->inverse) & (n - 1)] = j; |
| 135 | } |
| 136 | } |
| 137 | } |
| 138 | } |
| 139 | |
| 140 | av_cold int ff_fft_init(FFTContext *s, int nbits, int inverse) |
| 141 | { |
| 142 | int i, j, n; |
| 143 | |
| 144 | if (nbits < 2 || nbits > 16) |
| 145 | goto fail; |
| 146 | s->nbits = nbits; |
| 147 | n = 1 << nbits; |
| 148 | |
| 149 | s->revtab = av_malloc(n * sizeof(uint16_t)); |
| 150 | if (!s->revtab) |
| 151 | goto fail; |
| 152 | s->tmp_buf = av_malloc(n * sizeof(FFTComplex)); |
| 153 | if (!s->tmp_buf) |
| 154 | goto fail; |
| 155 | s->inverse = inverse; |
| 156 | s->fft_permutation = FF_FFT_PERM_DEFAULT; |
| 157 | |
| 158 | s->fft_permute = fft_permute_c; |
| 159 | s->fft_calc = fft_calc_c; |
| 160 | #if CONFIG_MDCT |
| 161 | s->imdct_calc = ff_imdct_calc_c; |
| 162 | s->imdct_half = ff_imdct_half_c; |
| 163 | s->mdct_calc = ff_mdct_calc_c; |
| 164 | #endif |
| 165 | |
| 166 | #if FFT_FIXED_32 |
| 167 | { |
| 168 | int n=0; |
| 169 | ff_fft_lut_init(ff_fft_offsets_lut, 0, 1 << 16, &n); |
| 170 | } |
| 171 | #else /* FFT_FIXED_32 */ |
| 172 | #if FFT_FLOAT |
| 173 | if (ARCH_AARCH64) ff_fft_init_aarch64(s); |
| 174 | if (ARCH_ARM) ff_fft_init_arm(s); |
| 175 | if (ARCH_PPC) ff_fft_init_ppc(s); |
| 176 | if (ARCH_X86) ff_fft_init_x86(s); |
| 177 | if (CONFIG_MDCT) s->mdct_calcw = s->mdct_calc; |
| 178 | if (HAVE_MIPSFPU) ff_fft_init_mips(s); |
| 179 | #else |
| 180 | if (CONFIG_MDCT) s->mdct_calcw = ff_mdct_calcw_c; |
| 181 | if (ARCH_ARM) ff_fft_fixed_init_arm(s); |
| 182 | #endif |
| 183 | for(j=4; j<=nbits; j++) { |
| 184 | ff_init_ff_cos_tabs(j); |
| 185 | } |
| 186 | #endif /* FFT_FIXED_32 */ |
| 187 | |
| 188 | |
| 189 | if (s->fft_permutation == FF_FFT_PERM_AVX) { |
| 190 | fft_perm_avx(s); |
| 191 | } else { |
| 192 | for(i=0; i<n; i++) { |
| 193 | j = i; |
| 194 | if (s->fft_permutation == FF_FFT_PERM_SWAP_LSBS) |
| 195 | j = (j&~3) | ((j>>1)&1) | ((j<<1)&2); |
| 196 | s->revtab[-split_radix_permutation(i, n, s->inverse) & (n-1)] = j; |
| 197 | } |
| 198 | } |
| 199 | |
| 200 | return 0; |
| 201 | fail: |
| 202 | av_freep(&s->revtab); |
| 203 | av_freep(&s->tmp_buf); |
| 204 | return -1; |
| 205 | } |
| 206 | |
| 207 | static void fft_permute_c(FFTContext *s, FFTComplex *z) |
| 208 | { |
| 209 | int j, np; |
| 210 | const uint16_t *revtab = s->revtab; |
| 211 | np = 1 << s->nbits; |
| 212 | /* TODO: handle split-radix permute in a more optimal way, probably in-place */ |
| 213 | for(j=0;j<np;j++) s->tmp_buf[revtab[j]] = z[j]; |
| 214 | memcpy(z, s->tmp_buf, np * sizeof(FFTComplex)); |
| 215 | } |
| 216 | |
| 217 | av_cold void ff_fft_end(FFTContext *s) |
| 218 | { |
| 219 | av_freep(&s->revtab); |
| 220 | av_freep(&s->tmp_buf); |
| 221 | } |
| 222 | |
| 223 | #if FFT_FIXED_32 |
| 224 | |
| 225 | static void fft_calc_c(FFTContext *s, FFTComplex *z) { |
| 226 | |
| 227 | int nbits, i, n, num_transforms, offset, step; |
| 228 | int n4, n2, n34; |
| 229 | FFTSample tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7, tmp8; |
| 230 | FFTComplex *tmpz; |
| 231 | const int fft_size = (1 << s->nbits); |
| 232 | int64_t accu; |
| 233 | |
| 234 | num_transforms = (0x2aab >> (16 - s->nbits)) | 1; |
| 235 | |
| 236 | for (n=0; n<num_transforms; n++){ |
| 237 | offset = ff_fft_offsets_lut[n] << 2; |
| 238 | tmpz = z + offset; |
| 239 | |
| 240 | tmp1 = tmpz[0].re + tmpz[1].re; |
| 241 | tmp5 = tmpz[2].re + tmpz[3].re; |
| 242 | tmp2 = tmpz[0].im + tmpz[1].im; |
| 243 | tmp6 = tmpz[2].im + tmpz[3].im; |
| 244 | tmp3 = tmpz[0].re - tmpz[1].re; |
| 245 | tmp8 = tmpz[2].im - tmpz[3].im; |
| 246 | tmp4 = tmpz[0].im - tmpz[1].im; |
| 247 | tmp7 = tmpz[2].re - tmpz[3].re; |
| 248 | |
| 249 | tmpz[0].re = tmp1 + tmp5; |
| 250 | tmpz[2].re = tmp1 - tmp5; |
| 251 | tmpz[0].im = tmp2 + tmp6; |
| 252 | tmpz[2].im = tmp2 - tmp6; |
| 253 | tmpz[1].re = tmp3 + tmp8; |
| 254 | tmpz[3].re = tmp3 - tmp8; |
| 255 | tmpz[1].im = tmp4 - tmp7; |
| 256 | tmpz[3].im = tmp4 + tmp7; |
| 257 | } |
| 258 | |
| 259 | if (fft_size < 8) |
| 260 | return; |
| 261 | |
| 262 | num_transforms = (num_transforms >> 1) | 1; |
| 263 | |
| 264 | for (n=0; n<num_transforms; n++){ |
| 265 | offset = ff_fft_offsets_lut[n] << 3; |
| 266 | tmpz = z + offset; |
| 267 | |
| 268 | tmp1 = tmpz[4].re + tmpz[5].re; |
| 269 | tmp3 = tmpz[6].re + tmpz[7].re; |
| 270 | tmp2 = tmpz[4].im + tmpz[5].im; |
| 271 | tmp4 = tmpz[6].im + tmpz[7].im; |
| 272 | tmp5 = tmp1 + tmp3; |
| 273 | tmp7 = tmp1 - tmp3; |
| 274 | tmp6 = tmp2 + tmp4; |
| 275 | tmp8 = tmp2 - tmp4; |
| 276 | |
| 277 | tmp1 = tmpz[4].re - tmpz[5].re; |
| 278 | tmp2 = tmpz[4].im - tmpz[5].im; |
| 279 | tmp3 = tmpz[6].re - tmpz[7].re; |
| 280 | tmp4 = tmpz[6].im - tmpz[7].im; |
| 281 | |
| 282 | tmpz[4].re = tmpz[0].re - tmp5; |
| 283 | tmpz[0].re = tmpz[0].re + tmp5; |
| 284 | tmpz[4].im = tmpz[0].im - tmp6; |
| 285 | tmpz[0].im = tmpz[0].im + tmp6; |
| 286 | tmpz[6].re = tmpz[2].re - tmp8; |
| 287 | tmpz[2].re = tmpz[2].re + tmp8; |
| 288 | tmpz[6].im = tmpz[2].im + tmp7; |
| 289 | tmpz[2].im = tmpz[2].im - tmp7; |
| 290 | |
| 291 | accu = (int64_t)Q31(M_SQRT1_2)*(tmp1 + tmp2); |
| 292 | tmp5 = (int32_t)((accu + 0x40000000) >> 31); |
| 293 | accu = (int64_t)Q31(M_SQRT1_2)*(tmp3 - tmp4); |
| 294 | tmp7 = (int32_t)((accu + 0x40000000) >> 31); |
| 295 | accu = (int64_t)Q31(M_SQRT1_2)*(tmp2 - tmp1); |
| 296 | tmp6 = (int32_t)((accu + 0x40000000) >> 31); |
| 297 | accu = (int64_t)Q31(M_SQRT1_2)*(tmp3 + tmp4); |
| 298 | tmp8 = (int32_t)((accu + 0x40000000) >> 31); |
| 299 | tmp1 = tmp5 + tmp7; |
| 300 | tmp3 = tmp5 - tmp7; |
| 301 | tmp2 = tmp6 + tmp8; |
| 302 | tmp4 = tmp6 - tmp8; |
| 303 | |
| 304 | tmpz[5].re = tmpz[1].re - tmp1; |
| 305 | tmpz[1].re = tmpz[1].re + tmp1; |
| 306 | tmpz[5].im = tmpz[1].im - tmp2; |
| 307 | tmpz[1].im = tmpz[1].im + tmp2; |
| 308 | tmpz[7].re = tmpz[3].re - tmp4; |
| 309 | tmpz[3].re = tmpz[3].re + tmp4; |
| 310 | tmpz[7].im = tmpz[3].im + tmp3; |
| 311 | tmpz[3].im = tmpz[3].im - tmp3; |
| 312 | } |
| 313 | |
| 314 | step = 1 << ((MAX_LOG2_NFFT-4) - 4); |
| 315 | n4 = 4; |
| 316 | |
| 317 | for (nbits=4; nbits<=s->nbits; nbits++){ |
| 318 | n2 = 2*n4; |
| 319 | n34 = 3*n4; |
| 320 | num_transforms = (num_transforms >> 1) | 1; |
| 321 | |
| 322 | for (n=0; n<num_transforms; n++){ |
| 323 | const FFTSample *w_re_ptr = ff_w_tab_sr + step; |
| 324 | const FFTSample *w_im_ptr = ff_w_tab_sr + MAX_FFT_SIZE/(4*16) - step; |
| 325 | offset = ff_fft_offsets_lut[n] << nbits; |
| 326 | tmpz = z + offset; |
| 327 | |
| 328 | tmp5 = tmpz[ n2].re + tmpz[n34].re; |
| 329 | tmp1 = tmpz[ n2].re - tmpz[n34].re; |
| 330 | tmp6 = tmpz[ n2].im + tmpz[n34].im; |
| 331 | tmp2 = tmpz[ n2].im - tmpz[n34].im; |
| 332 | |
| 333 | tmpz[ n2].re = tmpz[ 0].re - tmp5; |
| 334 | tmpz[ 0].re = tmpz[ 0].re + tmp5; |
| 335 | tmpz[ n2].im = tmpz[ 0].im - tmp6; |
| 336 | tmpz[ 0].im = tmpz[ 0].im + tmp6; |
| 337 | tmpz[n34].re = tmpz[n4].re - tmp2; |
| 338 | tmpz[ n4].re = tmpz[n4].re + tmp2; |
| 339 | tmpz[n34].im = tmpz[n4].im + tmp1; |
| 340 | tmpz[ n4].im = tmpz[n4].im - tmp1; |
| 341 | |
| 342 | for (i=1; i<n4; i++){ |
| 343 | FFTSample w_re = w_re_ptr[0]; |
| 344 | FFTSample w_im = w_im_ptr[0]; |
| 345 | accu = (int64_t)w_re*tmpz[ n2+i].re; |
| 346 | accu += (int64_t)w_im*tmpz[ n2+i].im; |
| 347 | tmp1 = (int32_t)((accu + 0x40000000) >> 31); |
| 348 | accu = (int64_t)w_re*tmpz[ n2+i].im; |
| 349 | accu -= (int64_t)w_im*tmpz[ n2+i].re; |
| 350 | tmp2 = (int32_t)((accu + 0x40000000) >> 31); |
| 351 | accu = (int64_t)w_re*tmpz[n34+i].re; |
| 352 | accu -= (int64_t)w_im*tmpz[n34+i].im; |
| 353 | tmp3 = (int32_t)((accu + 0x40000000) >> 31); |
| 354 | accu = (int64_t)w_re*tmpz[n34+i].im; |
| 355 | accu += (int64_t)w_im*tmpz[n34+i].re; |
| 356 | tmp4 = (int32_t)((accu + 0x40000000) >> 31); |
| 357 | |
| 358 | tmp5 = tmp1 + tmp3; |
| 359 | tmp1 = tmp1 - tmp3; |
| 360 | tmp6 = tmp2 + tmp4; |
| 361 | tmp2 = tmp2 - tmp4; |
| 362 | |
| 363 | tmpz[ n2+i].re = tmpz[ i].re - tmp5; |
| 364 | tmpz[ i].re = tmpz[ i].re + tmp5; |
| 365 | tmpz[ n2+i].im = tmpz[ i].im - tmp6; |
| 366 | tmpz[ i].im = tmpz[ i].im + tmp6; |
| 367 | tmpz[n34+i].re = tmpz[n4+i].re - tmp2; |
| 368 | tmpz[ n4+i].re = tmpz[n4+i].re + tmp2; |
| 369 | tmpz[n34+i].im = tmpz[n4+i].im + tmp1; |
| 370 | tmpz[ n4+i].im = tmpz[n4+i].im - tmp1; |
| 371 | |
| 372 | w_re_ptr += step; |
| 373 | w_im_ptr -= step; |
| 374 | } |
| 375 | } |
| 376 | step >>= 1; |
| 377 | n4 <<= 1; |
| 378 | } |
| 379 | } |
| 380 | |
| 381 | #else /* FFT_FIXED_32 */ |
| 382 | |
| 383 | #define BUTTERFLIES(a0,a1,a2,a3) {\ |
| 384 | BF(t3, t5, t5, t1);\ |
| 385 | BF(a2.re, a0.re, a0.re, t5);\ |
| 386 | BF(a3.im, a1.im, a1.im, t3);\ |
| 387 | BF(t4, t6, t2, t6);\ |
| 388 | BF(a3.re, a1.re, a1.re, t4);\ |
| 389 | BF(a2.im, a0.im, a0.im, t6);\ |
| 390 | } |
| 391 | |
| 392 | // force loading all the inputs before storing any. |
| 393 | // this is slightly slower for small data, but avoids store->load aliasing |
| 394 | // for addresses separated by large powers of 2. |
| 395 | #define BUTTERFLIES_BIG(a0,a1,a2,a3) {\ |
| 396 | FFTSample r0=a0.re, i0=a0.im, r1=a1.re, i1=a1.im;\ |
| 397 | BF(t3, t5, t5, t1);\ |
| 398 | BF(a2.re, a0.re, r0, t5);\ |
| 399 | BF(a3.im, a1.im, i1, t3);\ |
| 400 | BF(t4, t6, t2, t6);\ |
| 401 | BF(a3.re, a1.re, r1, t4);\ |
| 402 | BF(a2.im, a0.im, i0, t6);\ |
| 403 | } |
| 404 | |
| 405 | #define TRANSFORM(a0,a1,a2,a3,wre,wim) {\ |
| 406 | CMUL(t1, t2, a2.re, a2.im, wre, -wim);\ |
| 407 | CMUL(t5, t6, a3.re, a3.im, wre, wim);\ |
| 408 | BUTTERFLIES(a0,a1,a2,a3)\ |
| 409 | } |
| 410 | |
| 411 | #define TRANSFORM_ZERO(a0,a1,a2,a3) {\ |
| 412 | t1 = a2.re;\ |
| 413 | t2 = a2.im;\ |
| 414 | t5 = a3.re;\ |
| 415 | t6 = a3.im;\ |
| 416 | BUTTERFLIES(a0,a1,a2,a3)\ |
| 417 | } |
| 418 | |
| 419 | /* z[0...8n-1], w[1...2n-1] */ |
| 420 | #define PASS(name)\ |
| 421 | static void name(FFTComplex *z, const FFTSample *wre, unsigned int n)\ |
| 422 | {\ |
| 423 | FFTDouble t1, t2, t3, t4, t5, t6;\ |
| 424 | int o1 = 2*n;\ |
| 425 | int o2 = 4*n;\ |
| 426 | int o3 = 6*n;\ |
| 427 | const FFTSample *wim = wre+o1;\ |
| 428 | n--;\ |
| 429 | \ |
| 430 | TRANSFORM_ZERO(z[0],z[o1],z[o2],z[o3]);\ |
| 431 | TRANSFORM(z[1],z[o1+1],z[o2+1],z[o3+1],wre[1],wim[-1]);\ |
| 432 | do {\ |
| 433 | z += 2;\ |
| 434 | wre += 2;\ |
| 435 | wim -= 2;\ |
| 436 | TRANSFORM(z[0],z[o1],z[o2],z[o3],wre[0],wim[0]);\ |
| 437 | TRANSFORM(z[1],z[o1+1],z[o2+1],z[o3+1],wre[1],wim[-1]);\ |
| 438 | } while(--n);\ |
| 439 | } |
| 440 | |
| 441 | PASS(pass) |
| 442 | #undef BUTTERFLIES |
| 443 | #define BUTTERFLIES BUTTERFLIES_BIG |
| 444 | PASS(pass_big) |
| 445 | |
| 446 | #define DECL_FFT(n,n2,n4)\ |
| 447 | static void fft##n(FFTComplex *z)\ |
| 448 | {\ |
| 449 | fft##n2(z);\ |
| 450 | fft##n4(z+n4*2);\ |
| 451 | fft##n4(z+n4*3);\ |
| 452 | pass(z,FFT_NAME(ff_cos_##n),n4/2);\ |
| 453 | } |
| 454 | |
| 455 | static void fft4(FFTComplex *z) |
| 456 | { |
| 457 | FFTDouble t1, t2, t3, t4, t5, t6, t7, t8; |
| 458 | |
| 459 | BF(t3, t1, z[0].re, z[1].re); |
| 460 | BF(t8, t6, z[3].re, z[2].re); |
| 461 | BF(z[2].re, z[0].re, t1, t6); |
| 462 | BF(t4, t2, z[0].im, z[1].im); |
| 463 | BF(t7, t5, z[2].im, z[3].im); |
| 464 | BF(z[3].im, z[1].im, t4, t8); |
| 465 | BF(z[3].re, z[1].re, t3, t7); |
| 466 | BF(z[2].im, z[0].im, t2, t5); |
| 467 | } |
| 468 | |
| 469 | static void fft8(FFTComplex *z) |
| 470 | { |
| 471 | FFTDouble t1, t2, t3, t4, t5, t6; |
| 472 | |
| 473 | fft4(z); |
| 474 | |
| 475 | BF(t1, z[5].re, z[4].re, -z[5].re); |
| 476 | BF(t2, z[5].im, z[4].im, -z[5].im); |
| 477 | BF(t5, z[7].re, z[6].re, -z[7].re); |
| 478 | BF(t6, z[7].im, z[6].im, -z[7].im); |
| 479 | |
| 480 | BUTTERFLIES(z[0],z[2],z[4],z[6]); |
| 481 | TRANSFORM(z[1],z[3],z[5],z[7],sqrthalf,sqrthalf); |
| 482 | } |
| 483 | |
| 484 | #if !CONFIG_SMALL |
| 485 | static void fft16(FFTComplex *z) |
| 486 | { |
| 487 | FFTDouble t1, t2, t3, t4, t5, t6; |
| 488 | FFTSample cos_16_1 = FFT_NAME(ff_cos_16)[1]; |
| 489 | FFTSample cos_16_3 = FFT_NAME(ff_cos_16)[3]; |
| 490 | |
| 491 | fft8(z); |
| 492 | fft4(z+8); |
| 493 | fft4(z+12); |
| 494 | |
| 495 | TRANSFORM_ZERO(z[0],z[4],z[8],z[12]); |
| 496 | TRANSFORM(z[2],z[6],z[10],z[14],sqrthalf,sqrthalf); |
| 497 | TRANSFORM(z[1],z[5],z[9],z[13],cos_16_1,cos_16_3); |
| 498 | TRANSFORM(z[3],z[7],z[11],z[15],cos_16_3,cos_16_1); |
| 499 | } |
| 500 | #else |
| 501 | DECL_FFT(16,8,4) |
| 502 | #endif |
| 503 | DECL_FFT(32,16,8) |
| 504 | DECL_FFT(64,32,16) |
| 505 | DECL_FFT(128,64,32) |
| 506 | DECL_FFT(256,128,64) |
| 507 | DECL_FFT(512,256,128) |
| 508 | #if !CONFIG_SMALL |
| 509 | #define pass pass_big |
| 510 | #endif |
| 511 | DECL_FFT(1024,512,256) |
| 512 | DECL_FFT(2048,1024,512) |
| 513 | DECL_FFT(4096,2048,1024) |
| 514 | DECL_FFT(8192,4096,2048) |
| 515 | DECL_FFT(16384,8192,4096) |
| 516 | DECL_FFT(32768,16384,8192) |
| 517 | DECL_FFT(65536,32768,16384) |
| 518 | |
| 519 | static void (* const fft_dispatch[])(FFTComplex*) = { |
| 520 | fft4, fft8, fft16, fft32, fft64, fft128, fft256, fft512, fft1024, |
| 521 | fft2048, fft4096, fft8192, fft16384, fft32768, fft65536, |
| 522 | }; |
| 523 | |
| 524 | static void fft_calc_c(FFTContext *s, FFTComplex *z) |
| 525 | { |
| 526 | fft_dispatch[s->nbits-2](z); |
| 527 | } |
| 528 | #endif /* FFT_FIXED_32 */ |