2 Copyright (c) 2003-2004, Mark Borgerding
6 Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
8 * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
9 * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
10 * Neither the author nor the names of any contributors may be used to endorse or promote products derived from this software without specific prior written permission.
12 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
18 #include "kiss_fftr_s32.h"
19 #include "_kiss_fft_guts_s32.h"
21 struct kiss_fftr_s32_state
23 kiss_fft_s32_cfg substate;
24 kiss_fft_s32_cpx *tmpbuf;
25 kiss_fft_s32_cpx *super_twiddles;
32 kiss_fftr_s32_alloc (int nfft, int inverse_fft, void *mem, size_t * lenmem)
35 kiss_fftr_s32_cfg st = NULL;
36 size_t subsize, memneeded;
39 fprintf (stderr, "Real FFT optimization must be even.\n");
44 kiss_fft_s32_alloc (nfft, inverse_fft, NULL, &subsize);
45 memneeded = ALIGN_STRUCT (sizeof (struct kiss_fftr_s32_state))
46 + ALIGN_STRUCT (subsize)
47 + sizeof (kiss_fft_s32_cpx) * (nfft * 3 / 2);
50 st = (kiss_fftr_s32_cfg) KISS_FFT_S32_MALLOC (memneeded);
52 if (*lenmem >= memneeded)
53 st = (kiss_fftr_s32_cfg) mem;
59 st->substate = (kiss_fft_s32_cfg) (((char *) st) + ALIGN_STRUCT (sizeof (struct kiss_fftr_s32_state))); /*just beyond kiss_fftr_s32_state struct */
61 (kiss_fft_s32_cpx *) (((char *) st->substate) + ALIGN_STRUCT (subsize));
62 st->super_twiddles = st->tmpbuf + nfft;
63 kiss_fft_s32_alloc (nfft, inverse_fft, st->substate, &subsize);
65 for (i = 0; i < nfft / 2; ++i) {
67 -3.14159265358979323846264338327 * ((double) (i + 1) / nfft + .5);
71 kf_cexp (st->super_twiddles + i, phase);
77 kiss_fftr_s32 (kiss_fftr_s32_cfg st, const kiss_fft_s32_scalar * timedata,
78 kiss_fft_s32_cpx * freqdata)
80 /* input buffer timedata is stored row-wise */
82 kiss_fft_s32_cpx fpnk, fpk, f1k, f2k, tw, tdc;
84 /* kiss fft usage error: improper alloc */
85 g_return_if_fail (st->substate->inverse == 0);
87 ncfft = st->substate->nfft;
89 /*perform the parallel fft of two real signals packed in real,imag */
90 kiss_fft_s32 (st->substate, (const kiss_fft_s32_cpx *) timedata, st->tmpbuf);
91 /* The real part of the DC element of the frequency spectrum in st->tmpbuf
92 * contains the sum of the even-numbered elements of the input time sequence
93 * The imag part is the sum of the odd-numbered elements
95 * The sum of tdc.r and tdc.i is the sum of the input time sequence.
96 * yielding DC of input time sequence
97 * The difference of tdc.r - tdc.i is the sum of the input (dot product) [1,-1,1,-1...
98 * yielding Nyquist bin of input time sequence
101 tdc.r = st->tmpbuf[0].r;
102 tdc.i = st->tmpbuf[0].i;
104 CHECK_OVERFLOW_OP (tdc.r, +, tdc.i);
105 CHECK_OVERFLOW_OP (tdc.r, -, tdc.i);
106 freqdata[0].r = tdc.r + tdc.i;
107 freqdata[ncfft].r = tdc.r - tdc.i;
109 freqdata[ncfft].i = freqdata[0].i = _mm_set1_ps (0);
111 freqdata[ncfft].i = freqdata[0].i = 0;
114 for (k = 1; k <= ncfft / 2; ++k) {
116 fpnk.r = st->tmpbuf[ncfft - k].r;
117 fpnk.i = -st->tmpbuf[ncfft - k].i;
121 C_ADD (f1k, fpk, fpnk);
122 C_SUB (f2k, fpk, fpnk);
123 C_MUL (tw, f2k, st->super_twiddles[k - 1]);
125 freqdata[k].r = HALF_OF (f1k.r + tw.r);
126 freqdata[k].i = HALF_OF (f1k.i + tw.i);
127 freqdata[ncfft - k].r = HALF_OF (f1k.r - tw.r);
128 freqdata[ncfft - k].i = HALF_OF (tw.i - f1k.i);
133 kiss_fftri_s32 (kiss_fftr_s32_cfg st, const kiss_fft_s32_cpx * freqdata,
134 kiss_fft_s32_scalar * timedata)
136 /* input buffer timedata is stored row-wise */
139 /* kiss fft usage error: improper alloc */
140 g_return_if_fail (st->substate->inverse != 0);
142 ncfft = st->substate->nfft;
144 st->tmpbuf[0].r = freqdata[0].r + freqdata[ncfft].r;
145 st->tmpbuf[0].i = freqdata[0].r - freqdata[ncfft].r;
146 C_FIXDIV (st->tmpbuf[0], 2);
148 for (k = 1; k <= ncfft / 2; ++k) {
149 kiss_fft_s32_cpx fk, fnkc, fek, fok, tmp;
152 fnkc.r = freqdata[ncfft - k].r;
153 fnkc.i = -freqdata[ncfft - k].i;
157 C_ADD (fek, fk, fnkc);
158 C_SUB (tmp, fk, fnkc);
159 C_MUL (fok, tmp, st->super_twiddles[k - 1]);
160 C_ADD (st->tmpbuf[k], fek, fok);
161 C_SUB (st->tmpbuf[ncfft - k], fek, fok);
163 st->tmpbuf[ncfft - k].i *= _mm_set1_ps (-1.0);
165 st->tmpbuf[ncfft - k].i *= -1;
168 kiss_fft_s32 (st->substate, st->tmpbuf, (kiss_fft_s32_cpx *) timedata);