| /* |
| * FFT/IFFT transforms |
| * Copyright (c) 2008 Loren Merritt |
| * Copyright (c) 2002 Fabrice Bellard |
| * Partly based on libdjbfft by D. J. Bernstein |
| * |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| /** |
| * @file |
| * FFT/IFFT transforms. |
| */ |
| |
| #include <stdlib.h> |
| #include <string.h> |
| #include "libavutil/mathematics.h" |
| #include "libavutil/thread.h" |
| #include "fft.h" |
| #include "fft-internal.h" |
| |
| #if FFT_FIXED_32 |
| #include "fft_table.h" |
| #else /* FFT_FIXED_32 */ |
| |
| /* cos(2*pi*x/n) for 0<=x<=n/4, followed by its reverse */ |
| #if !CONFIG_HARDCODED_TABLES |
| COSTABLE(16); |
| COSTABLE(32); |
| COSTABLE(64); |
| COSTABLE(128); |
| COSTABLE(256); |
| COSTABLE(512); |
| COSTABLE(1024); |
| COSTABLE(2048); |
| COSTABLE(4096); |
| COSTABLE(8192); |
| COSTABLE(16384); |
| COSTABLE(32768); |
| COSTABLE(65536); |
| COSTABLE(131072); |
| |
| static av_cold void init_ff_cos_tabs(int index) |
| { |
| int i; |
| int m = 1<<index; |
| double freq = 2*M_PI/m; |
| FFTSample *tab = FFT_NAME(ff_cos_tabs)[index]; |
| for(i=0; i<=m/4; i++) |
| tab[i] = FIX15(cos(i*freq)); |
| for(i=1; i<m/4; i++) |
| tab[m/2-i] = tab[i]; |
| } |
| |
| typedef struct CosTabsInitOnce { |
| void (*func)(void); |
| AVOnce control; |
| } CosTabsInitOnce; |
| |
| #define INIT_FF_COS_TABS_FUNC(index, size) \ |
| static av_cold void init_ff_cos_tabs_ ## size (void)\ |
| { \ |
| init_ff_cos_tabs(index); \ |
| } |
| |
| INIT_FF_COS_TABS_FUNC(4, 16) |
| INIT_FF_COS_TABS_FUNC(5, 32) |
| INIT_FF_COS_TABS_FUNC(6, 64) |
| INIT_FF_COS_TABS_FUNC(7, 128) |
| INIT_FF_COS_TABS_FUNC(8, 256) |
| INIT_FF_COS_TABS_FUNC(9, 512) |
| INIT_FF_COS_TABS_FUNC(10, 1024) |
| INIT_FF_COS_TABS_FUNC(11, 2048) |
| INIT_FF_COS_TABS_FUNC(12, 4096) |
| INIT_FF_COS_TABS_FUNC(13, 8192) |
| INIT_FF_COS_TABS_FUNC(14, 16384) |
| INIT_FF_COS_TABS_FUNC(15, 32768) |
| INIT_FF_COS_TABS_FUNC(16, 65536) |
| INIT_FF_COS_TABS_FUNC(17, 131072) |
| |
| static CosTabsInitOnce cos_tabs_init_once[] = { |
| { NULL }, |
| { NULL }, |
| { NULL }, |
| { NULL }, |
| { init_ff_cos_tabs_16, AV_ONCE_INIT }, |
| { init_ff_cos_tabs_32, AV_ONCE_INIT }, |
| { init_ff_cos_tabs_64, AV_ONCE_INIT }, |
| { init_ff_cos_tabs_128, AV_ONCE_INIT }, |
| { init_ff_cos_tabs_256, AV_ONCE_INIT }, |
| { init_ff_cos_tabs_512, AV_ONCE_INIT }, |
| { init_ff_cos_tabs_1024, AV_ONCE_INIT }, |
| { init_ff_cos_tabs_2048, AV_ONCE_INIT }, |
| { init_ff_cos_tabs_4096, AV_ONCE_INIT }, |
| { init_ff_cos_tabs_8192, AV_ONCE_INIT }, |
| { init_ff_cos_tabs_16384, AV_ONCE_INIT }, |
| { init_ff_cos_tabs_32768, AV_ONCE_INIT }, |
| { init_ff_cos_tabs_65536, AV_ONCE_INIT }, |
| { init_ff_cos_tabs_131072, AV_ONCE_INIT }, |
| }; |
| |
| #endif |
| COSTABLE_CONST FFTSample * const FFT_NAME(ff_cos_tabs)[] = { |
| NULL, NULL, NULL, NULL, |
| FFT_NAME(ff_cos_16), |
| FFT_NAME(ff_cos_32), |
| FFT_NAME(ff_cos_64), |
| FFT_NAME(ff_cos_128), |
| FFT_NAME(ff_cos_256), |
| FFT_NAME(ff_cos_512), |
| FFT_NAME(ff_cos_1024), |
| FFT_NAME(ff_cos_2048), |
| FFT_NAME(ff_cos_4096), |
| FFT_NAME(ff_cos_8192), |
| FFT_NAME(ff_cos_16384), |
| FFT_NAME(ff_cos_32768), |
| FFT_NAME(ff_cos_65536), |
| FFT_NAME(ff_cos_131072), |
| }; |
| |
| #endif /* FFT_FIXED_32 */ |
| |
| static void fft_permute_c(FFTContext *s, FFTComplex *z); |
| static void fft_calc_c(FFTContext *s, FFTComplex *z); |
| |
| static int split_radix_permutation(int i, int n, int inverse) |
| { |
| int m; |
| if(n <= 2) return i&1; |
| m = n >> 1; |
| if(!(i&m)) return split_radix_permutation(i, m, inverse)*2; |
| m >>= 1; |
| if(inverse == !(i&m)) return split_radix_permutation(i, m, inverse)*4 + 1; |
| else return split_radix_permutation(i, m, inverse)*4 - 1; |
| } |
| |
| av_cold void ff_init_ff_cos_tabs(int index) |
| { |
| #if (!CONFIG_HARDCODED_TABLES) && (!FFT_FIXED_32) |
| ff_thread_once(&cos_tabs_init_once[index].control, cos_tabs_init_once[index].func); |
| #endif |
| } |
| |
| static const int avx_tab[] = { |
| 0, 4, 1, 5, 8, 12, 9, 13, 2, 6, 3, 7, 10, 14, 11, 15 |
| }; |
| |
| static int is_second_half_of_fft32(int i, int n) |
| { |
| if (n <= 32) |
| return i >= 16; |
| else if (i < n/2) |
| return is_second_half_of_fft32(i, n/2); |
| else if (i < 3*n/4) |
| return is_second_half_of_fft32(i - n/2, n/4); |
| else |
| return is_second_half_of_fft32(i - 3*n/4, n/4); |
| } |
| |
| static av_cold void fft_perm_avx(FFTContext *s) |
| { |
| int i; |
| int n = 1 << s->nbits; |
| |
| for (i = 0; i < n; i += 16) { |
| int k; |
| if (is_second_half_of_fft32(i, n)) { |
| for (k = 0; k < 16; k++) |
| s->revtab[-split_radix_permutation(i + k, n, s->inverse) & (n - 1)] = |
| i + avx_tab[k]; |
| |
| } else { |
| for (k = 0; k < 16; k++) { |
| int j = i + k; |
| j = (j & ~7) | ((j >> 1) & 3) | ((j << 2) & 4); |
| s->revtab[-split_radix_permutation(i + k, n, s->inverse) & (n - 1)] = j; |
| } |
| } |
| } |
| } |
| |
| av_cold int ff_fft_init(FFTContext *s, int nbits, int inverse) |
| { |
| int i, j, n; |
| |
| s->revtab = NULL; |
| s->revtab32 = NULL; |
| |
| if (nbits < 2 || nbits > 17) |
| goto fail; |
| s->nbits = nbits; |
| n = 1 << nbits; |
| |
| if (nbits <= 16) { |
| s->revtab = av_malloc(n * sizeof(uint16_t)); |
| if (!s->revtab) |
| goto fail; |
| } else { |
| s->revtab32 = av_malloc(n * sizeof(uint32_t)); |
| if (!s->revtab32) |
| goto fail; |
| } |
| s->tmp_buf = av_malloc(n * sizeof(FFTComplex)); |
| if (!s->tmp_buf) |
| goto fail; |
| s->inverse = inverse; |
| s->fft_permutation = FF_FFT_PERM_DEFAULT; |
| |
| s->fft_permute = fft_permute_c; |
| s->fft_calc = fft_calc_c; |
| #if CONFIG_MDCT |
| s->imdct_calc = ff_imdct_calc_c; |
| s->imdct_half = ff_imdct_half_c; |
| s->mdct_calc = ff_mdct_calc_c; |
| #endif |
| |
| #if FFT_FIXED_32 |
| ff_fft_lut_init(); |
| #else /* FFT_FIXED_32 */ |
| #if FFT_FLOAT |
| if (ARCH_AARCH64) ff_fft_init_aarch64(s); |
| if (ARCH_ARM) ff_fft_init_arm(s); |
| if (ARCH_PPC) ff_fft_init_ppc(s); |
| if (ARCH_X86) ff_fft_init_x86(s); |
| if (CONFIG_MDCT) s->mdct_calcw = s->mdct_calc; |
| if (HAVE_MIPSFPU) ff_fft_init_mips(s); |
| #else |
| if (CONFIG_MDCT) s->mdct_calcw = ff_mdct_calcw_c; |
| if (ARCH_ARM) ff_fft_fixed_init_arm(s); |
| #endif |
| for(j=4; j<=nbits; j++) { |
| ff_init_ff_cos_tabs(j); |
| } |
| #endif /* FFT_FIXED_32 */ |
| |
| |
| if (s->fft_permutation == FF_FFT_PERM_AVX) { |
| fft_perm_avx(s); |
| } else { |
| #define PROCESS_FFT_PERM_SWAP_LSBS(num) do {\ |
| for(i = 0; i < n; i++) {\ |
| int k;\ |
| j = i;\ |
| j = (j & ~3) | ((j >> 1) & 1) | ((j << 1) & 2);\ |
| k = -split_radix_permutation(i, n, s->inverse) & (n - 1);\ |
| s->revtab##num[k] = j;\ |
| } \ |
| } while(0); |
| |
| #define PROCESS_FFT_PERM_DEFAULT(num) do {\ |
| for(i = 0; i < n; i++) {\ |
| int k;\ |
| j = i;\ |
| k = -split_radix_permutation(i, n, s->inverse) & (n - 1);\ |
| s->revtab##num[k] = j;\ |
| } \ |
| } while(0); |
| |
| #define SPLIT_RADIX_PERMUTATION(num) do { \ |
| if (s->fft_permutation == FF_FFT_PERM_SWAP_LSBS) {\ |
| PROCESS_FFT_PERM_SWAP_LSBS(num) \ |
| } else {\ |
| PROCESS_FFT_PERM_DEFAULT(num) \ |
| }\ |
| } while(0); |
| |
| if (s->revtab) |
| SPLIT_RADIX_PERMUTATION() |
| if (s->revtab32) |
| SPLIT_RADIX_PERMUTATION(32) |
| |
| #undef PROCESS_FFT_PERM_DEFAULT |
| #undef PROCESS_FFT_PERM_SWAP_LSBS |
| #undef SPLIT_RADIX_PERMUTATION |
| } |
| |
| return 0; |
| fail: |
| av_freep(&s->revtab); |
| av_freep(&s->revtab32); |
| av_freep(&s->tmp_buf); |
| return -1; |
| } |
| |
| static void fft_permute_c(FFTContext *s, FFTComplex *z) |
| { |
| int j, np; |
| const uint16_t *revtab = s->revtab; |
| const uint32_t *revtab32 = s->revtab32; |
| np = 1 << s->nbits; |
| /* TODO: handle split-radix permute in a more optimal way, probably in-place */ |
| if (revtab) { |
| for(j=0;j<np;j++) s->tmp_buf[revtab[j]] = z[j]; |
| } else |
| for(j=0;j<np;j++) s->tmp_buf[revtab32[j]] = z[j]; |
| |
| memcpy(z, s->tmp_buf, np * sizeof(FFTComplex)); |
| } |
| |
| av_cold void ff_fft_end(FFTContext *s) |
| { |
| av_freep(&s->revtab); |
| av_freep(&s->revtab32); |
| av_freep(&s->tmp_buf); |
| } |
| |
| #if FFT_FIXED_32 |
| |
| static void fft_calc_c(FFTContext *s, FFTComplex *z) { |
| |
| int nbits, i, n, num_transforms, offset, step; |
| int n4, n2, n34; |
| unsigned tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7, tmp8; |
| FFTComplex *tmpz; |
| const int fft_size = (1 << s->nbits); |
| int64_t accu; |
| |
| num_transforms = (0x2aab >> (16 - s->nbits)) | 1; |
| |
| for (n=0; n<num_transforms; n++){ |
| offset = ff_fft_offsets_lut[n] << 2; |
| tmpz = z + offset; |
| |
| tmp1 = tmpz[0].re + (unsigned)tmpz[1].re; |
| tmp5 = tmpz[2].re + (unsigned)tmpz[3].re; |
| tmp2 = tmpz[0].im + (unsigned)tmpz[1].im; |
| tmp6 = tmpz[2].im + (unsigned)tmpz[3].im; |
| tmp3 = tmpz[0].re - (unsigned)tmpz[1].re; |
| tmp8 = tmpz[2].im - (unsigned)tmpz[3].im; |
| tmp4 = tmpz[0].im - (unsigned)tmpz[1].im; |
| tmp7 = tmpz[2].re - (unsigned)tmpz[3].re; |
| |
| tmpz[0].re = tmp1 + tmp5; |
| tmpz[2].re = tmp1 - tmp5; |
| tmpz[0].im = tmp2 + tmp6; |
| tmpz[2].im = tmp2 - tmp6; |
| tmpz[1].re = tmp3 + tmp8; |
| tmpz[3].re = tmp3 - tmp8; |
| tmpz[1].im = tmp4 - tmp7; |
| tmpz[3].im = tmp4 + tmp7; |
| } |
| |
| if (fft_size < 8) |
| return; |
| |
| num_transforms = (num_transforms >> 1) | 1; |
| |
| for (n=0; n<num_transforms; n++){ |
| offset = ff_fft_offsets_lut[n] << 3; |
| tmpz = z + offset; |
| |
| tmp1 = tmpz[4].re + (unsigned)tmpz[5].re; |
| tmp3 = tmpz[6].re + (unsigned)tmpz[7].re; |
| tmp2 = tmpz[4].im + (unsigned)tmpz[5].im; |
| tmp4 = tmpz[6].im + (unsigned)tmpz[7].im; |
| tmp5 = tmp1 + tmp3; |
| tmp7 = tmp1 - tmp3; |
| tmp6 = tmp2 + tmp4; |
| tmp8 = tmp2 - tmp4; |
| |
| tmp1 = tmpz[4].re - (unsigned)tmpz[5].re; |
| tmp2 = tmpz[4].im - (unsigned)tmpz[5].im; |
| tmp3 = tmpz[6].re - (unsigned)tmpz[7].re; |
| tmp4 = tmpz[6].im - (unsigned)tmpz[7].im; |
| |
| tmpz[4].re = tmpz[0].re - tmp5; |
| tmpz[0].re = tmpz[0].re + tmp5; |
| tmpz[4].im = tmpz[0].im - tmp6; |
| tmpz[0].im = tmpz[0].im + tmp6; |
| tmpz[6].re = tmpz[2].re - tmp8; |
| tmpz[2].re = tmpz[2].re + tmp8; |
| tmpz[6].im = tmpz[2].im + tmp7; |
| tmpz[2].im = tmpz[2].im - tmp7; |
| |
| accu = (int64_t)Q31(M_SQRT1_2)*(int)(tmp1 + tmp2); |
| tmp5 = (int32_t)((accu + 0x40000000) >> 31); |
| accu = (int64_t)Q31(M_SQRT1_2)*(int)(tmp3 - tmp4); |
| tmp7 = (int32_t)((accu + 0x40000000) >> 31); |
| accu = (int64_t)Q31(M_SQRT1_2)*(int)(tmp2 - tmp1); |
| tmp6 = (int32_t)((accu + 0x40000000) >> 31); |
| accu = (int64_t)Q31(M_SQRT1_2)*(int)(tmp3 + tmp4); |
| tmp8 = (int32_t)((accu + 0x40000000) >> 31); |
| tmp1 = tmp5 + tmp7; |
| tmp3 = tmp5 - tmp7; |
| tmp2 = tmp6 + tmp8; |
| tmp4 = tmp6 - tmp8; |
| |
| tmpz[5].re = tmpz[1].re - tmp1; |
| tmpz[1].re = tmpz[1].re + tmp1; |
| tmpz[5].im = tmpz[1].im - tmp2; |
| tmpz[1].im = tmpz[1].im + tmp2; |
| tmpz[7].re = tmpz[3].re - tmp4; |
| tmpz[3].re = tmpz[3].re + tmp4; |
| tmpz[7].im = tmpz[3].im + tmp3; |
| tmpz[3].im = tmpz[3].im - tmp3; |
| } |
| |
| step = 1 << ((MAX_LOG2_NFFT-4) - 4); |
| n4 = 4; |
| |
| for (nbits=4; nbits<=s->nbits; nbits++){ |
| n2 = 2*n4; |
| n34 = 3*n4; |
| num_transforms = (num_transforms >> 1) | 1; |
| |
| for (n=0; n<num_transforms; n++){ |
| const FFTSample *w_re_ptr = ff_w_tab_sr + step; |
| const FFTSample *w_im_ptr = ff_w_tab_sr + MAX_FFT_SIZE/(4*16) - step; |
| offset = ff_fft_offsets_lut[n] << nbits; |
| tmpz = z + offset; |
| |
| tmp5 = tmpz[ n2].re + (unsigned)tmpz[n34].re; |
| tmp1 = tmpz[ n2].re - (unsigned)tmpz[n34].re; |
| tmp6 = tmpz[ n2].im + (unsigned)tmpz[n34].im; |
| tmp2 = tmpz[ n2].im - (unsigned)tmpz[n34].im; |
| |
| tmpz[ n2].re = tmpz[ 0].re - tmp5; |
| tmpz[ 0].re = tmpz[ 0].re + tmp5; |
| tmpz[ n2].im = tmpz[ 0].im - tmp6; |
| tmpz[ 0].im = tmpz[ 0].im + tmp6; |
| tmpz[n34].re = tmpz[n4].re - tmp2; |
| tmpz[ n4].re = tmpz[n4].re + tmp2; |
| tmpz[n34].im = tmpz[n4].im + tmp1; |
| tmpz[ n4].im = tmpz[n4].im - tmp1; |
| |
| for (i=1; i<n4; i++){ |
| FFTSample w_re = w_re_ptr[0]; |
| FFTSample w_im = w_im_ptr[0]; |
| accu = (int64_t)w_re*tmpz[ n2+i].re; |
| accu += (int64_t)w_im*tmpz[ n2+i].im; |
| tmp1 = (int32_t)((accu + 0x40000000) >> 31); |
| accu = (int64_t)w_re*tmpz[ n2+i].im; |
| accu -= (int64_t)w_im*tmpz[ n2+i].re; |
| tmp2 = (int32_t)((accu + 0x40000000) >> 31); |
| accu = (int64_t)w_re*tmpz[n34+i].re; |
| accu -= (int64_t)w_im*tmpz[n34+i].im; |
| tmp3 = (int32_t)((accu + 0x40000000) >> 31); |
| accu = (int64_t)w_re*tmpz[n34+i].im; |
| accu += (int64_t)w_im*tmpz[n34+i].re; |
| tmp4 = (int32_t)((accu + 0x40000000) >> 31); |
| |
| tmp5 = tmp1 + tmp3; |
| tmp1 = tmp1 - tmp3; |
| tmp6 = tmp2 + tmp4; |
| tmp2 = tmp2 - tmp4; |
| |
| tmpz[ n2+i].re = tmpz[ i].re - tmp5; |
| tmpz[ i].re = tmpz[ i].re + tmp5; |
| tmpz[ n2+i].im = tmpz[ i].im - tmp6; |
| tmpz[ i].im = tmpz[ i].im + tmp6; |
| tmpz[n34+i].re = tmpz[n4+i].re - tmp2; |
| tmpz[ n4+i].re = tmpz[n4+i].re + tmp2; |
| tmpz[n34+i].im = tmpz[n4+i].im + tmp1; |
| tmpz[ n4+i].im = tmpz[n4+i].im - tmp1; |
| |
| w_re_ptr += step; |
| w_im_ptr -= step; |
| } |
| } |
| step >>= 1; |
| n4 <<= 1; |
| } |
| } |
| |
| #else /* FFT_FIXED_32 */ |
| |
| #define BUTTERFLIES(a0,a1,a2,a3) {\ |
| BF(t3, t5, t5, t1);\ |
| BF(a2.re, a0.re, a0.re, t5);\ |
| BF(a3.im, a1.im, a1.im, t3);\ |
| BF(t4, t6, t2, t6);\ |
| BF(a3.re, a1.re, a1.re, t4);\ |
| BF(a2.im, a0.im, a0.im, t6);\ |
| } |
| |
| // force loading all the inputs before storing any. |
| // this is slightly slower for small data, but avoids store->load aliasing |
| // for addresses separated by large powers of 2. |
| #define BUTTERFLIES_BIG(a0,a1,a2,a3) {\ |
| FFTSample r0=a0.re, i0=a0.im, r1=a1.re, i1=a1.im;\ |
| BF(t3, t5, t5, t1);\ |
| BF(a2.re, a0.re, r0, t5);\ |
| BF(a3.im, a1.im, i1, t3);\ |
| BF(t4, t6, t2, t6);\ |
| BF(a3.re, a1.re, r1, t4);\ |
| BF(a2.im, a0.im, i0, t6);\ |
| } |
| |
| #define TRANSFORM(a0,a1,a2,a3,wre,wim) {\ |
| CMUL(t1, t2, a2.re, a2.im, wre, -wim);\ |
| CMUL(t5, t6, a3.re, a3.im, wre, wim);\ |
| BUTTERFLIES(a0,a1,a2,a3)\ |
| } |
| |
| #define TRANSFORM_ZERO(a0,a1,a2,a3) {\ |
| t1 = a2.re;\ |
| t2 = a2.im;\ |
| t5 = a3.re;\ |
| t6 = a3.im;\ |
| BUTTERFLIES(a0,a1,a2,a3)\ |
| } |
| |
| /* z[0...8n-1], w[1...2n-1] */ |
| #define PASS(name)\ |
| static void name(FFTComplex *z, const FFTSample *wre, unsigned int n)\ |
| {\ |
| FFTDouble t1, t2, t3, t4, t5, t6;\ |
| int o1 = 2*n;\ |
| int o2 = 4*n;\ |
| int o3 = 6*n;\ |
| const FFTSample *wim = wre+o1;\ |
| n--;\ |
| \ |
| TRANSFORM_ZERO(z[0],z[o1],z[o2],z[o3]);\ |
| TRANSFORM(z[1],z[o1+1],z[o2+1],z[o3+1],wre[1],wim[-1]);\ |
| do {\ |
| z += 2;\ |
| wre += 2;\ |
| wim -= 2;\ |
| TRANSFORM(z[0],z[o1],z[o2],z[o3],wre[0],wim[0]);\ |
| TRANSFORM(z[1],z[o1+1],z[o2+1],z[o3+1],wre[1],wim[-1]);\ |
| } while(--n);\ |
| } |
| |
| PASS(pass) |
| #if !CONFIG_SMALL |
| #undef BUTTERFLIES |
| #define BUTTERFLIES BUTTERFLIES_BIG |
| PASS(pass_big) |
| #endif |
| |
| #define DECL_FFT(n,n2,n4)\ |
| static void fft##n(FFTComplex *z)\ |
| {\ |
| fft##n2(z);\ |
| fft##n4(z+n4*2);\ |
| fft##n4(z+n4*3);\ |
| pass(z,FFT_NAME(ff_cos_##n),n4/2);\ |
| } |
| |
| static void fft4(FFTComplex *z) |
| { |
| FFTDouble t1, t2, t3, t4, t5, t6, t7, t8; |
| |
| BF(t3, t1, z[0].re, z[1].re); |
| BF(t8, t6, z[3].re, z[2].re); |
| BF(z[2].re, z[0].re, t1, t6); |
| BF(t4, t2, z[0].im, z[1].im); |
| BF(t7, t5, z[2].im, z[3].im); |
| BF(z[3].im, z[1].im, t4, t8); |
| BF(z[3].re, z[1].re, t3, t7); |
| BF(z[2].im, z[0].im, t2, t5); |
| } |
| |
| static void fft8(FFTComplex *z) |
| { |
| FFTDouble t1, t2, t3, t4, t5, t6; |
| |
| fft4(z); |
| |
| BF(t1, z[5].re, z[4].re, -z[5].re); |
| BF(t2, z[5].im, z[4].im, -z[5].im); |
| BF(t5, z[7].re, z[6].re, -z[7].re); |
| BF(t6, z[7].im, z[6].im, -z[7].im); |
| |
| BUTTERFLIES(z[0],z[2],z[4],z[6]); |
| TRANSFORM(z[1],z[3],z[5],z[7],sqrthalf,sqrthalf); |
| } |
| |
| #if !CONFIG_SMALL |
| static void fft16(FFTComplex *z) |
| { |
| FFTDouble t1, t2, t3, t4, t5, t6; |
| FFTSample cos_16_1 = FFT_NAME(ff_cos_16)[1]; |
| FFTSample cos_16_3 = FFT_NAME(ff_cos_16)[3]; |
| |
| fft8(z); |
| fft4(z+8); |
| fft4(z+12); |
| |
| TRANSFORM_ZERO(z[0],z[4],z[8],z[12]); |
| TRANSFORM(z[2],z[6],z[10],z[14],sqrthalf,sqrthalf); |
| TRANSFORM(z[1],z[5],z[9],z[13],cos_16_1,cos_16_3); |
| TRANSFORM(z[3],z[7],z[11],z[15],cos_16_3,cos_16_1); |
| } |
| #else |
| DECL_FFT(16,8,4) |
| #endif |
| DECL_FFT(32,16,8) |
| DECL_FFT(64,32,16) |
| DECL_FFT(128,64,32) |
| DECL_FFT(256,128,64) |
| DECL_FFT(512,256,128) |
| #if !CONFIG_SMALL |
| #define pass pass_big |
| #endif |
| DECL_FFT(1024,512,256) |
| DECL_FFT(2048,1024,512) |
| DECL_FFT(4096,2048,1024) |
| DECL_FFT(8192,4096,2048) |
| DECL_FFT(16384,8192,4096) |
| DECL_FFT(32768,16384,8192) |
| DECL_FFT(65536,32768,16384) |
| DECL_FFT(131072,65536,32768) |
| |
| static void (* const fft_dispatch[])(FFTComplex*) = { |
| fft4, fft8, fft16, fft32, fft64, fft128, fft256, fft512, fft1024, |
| fft2048, fft4096, fft8192, fft16384, fft32768, fft65536, fft131072 |
| }; |
| |
| static void fft_calc_c(FFTContext *s, FFTComplex *z) |
| { |
| fft_dispatch[s->nbits-2](z); |
| } |
| #endif /* FFT_FIXED_32 */ |
