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.
15 #include "kiss_fftr_s16.h"
16 #include "_kiss_fft_guts_s16.h"
18 struct kiss_fftr_s16_state
20 kiss_fft_s16_cfg substate;
21 kiss_fft_s16_cpx *tmpbuf;
22 kiss_fft_s16_cpx *super_twiddles;
29 kiss_fftr_s16_alloc (int nfft, int inverse_fft, void *mem, size_t * lenmem)
32 kiss_fftr_s16_cfg st = NULL;
33 size_t subsize, memneeded;
36 fprintf (stderr, "Real FFT optimization must be even.\n");
41 kiss_fft_s16_alloc (nfft, inverse_fft, NULL, &subsize);
42 memneeded = ALIGN_STRUCT (sizeof (struct kiss_fftr_s16_state))
43 + ALIGN_STRUCT (subsize)
44 + sizeof (kiss_fft_s16_cpx) * (nfft * 3 / 2);
47 st = (kiss_fftr_s16_cfg) KISS_FFT_S16_MALLOC (memneeded);
49 if (*lenmem >= memneeded)
50 st = (kiss_fftr_s16_cfg) mem;
56 st->substate = (kiss_fft_s16_cfg) (((char *) st) + ALIGN_STRUCT (sizeof (struct kiss_fftr_s16_state))); /*just beyond kiss_fftr_s16_state struct */
58 (kiss_fft_s16_cpx *) (((char *) st->substate) + ALIGN_STRUCT (subsize));
59 st->super_twiddles = st->tmpbuf + nfft;
60 kiss_fft_s16_alloc (nfft, inverse_fft, st->substate, &subsize);
62 for (i = 0; i < nfft / 2; ++i) {
64 -3.14159265358979323846264338327 * ((double) (i + 1) / nfft + .5);
68 kf_cexp (st->super_twiddles + i, phase);
74 kiss_fftr_s16 (kiss_fftr_s16_cfg st, const kiss_fft_s16_scalar * timedata,
75 kiss_fft_s16_cpx * freqdata)
77 /* input buffer timedata is stored row-wise */
79 kiss_fft_s16_cpx fpnk, fpk, f1k, f2k, tw, tdc;
81 if (st->substate->inverse) {
82 fprintf (stderr, "kiss fft usage error: improper alloc\n");
86 ncfft = st->substate->nfft;
88 /*perform the parallel fft of two real signals packed in real,imag */
89 kiss_fft_s16 (st->substate, (const kiss_fft_s16_cpx *) timedata, st->tmpbuf);
90 /* The real part of the DC element of the frequency spectrum in st->tmpbuf
91 * contains the sum of the even-numbered elements of the input time sequence
92 * The imag part is the sum of the odd-numbered elements
94 * The sum of tdc.r and tdc.i is the sum of the input time sequence.
95 * yielding DC of input time sequence
96 * The difference of tdc.r - tdc.i is the sum of the input (dot product) [1,-1,1,-1...
97 * yielding Nyquist bin of input time sequence
100 tdc.r = st->tmpbuf[0].r;
101 tdc.i = st->tmpbuf[0].i;
103 CHECK_OVERFLOW_OP (tdc.r, +, tdc.i);
104 CHECK_OVERFLOW_OP (tdc.r, -, tdc.i);
105 freqdata[0].r = tdc.r + tdc.i;
106 freqdata[ncfft].r = tdc.r - tdc.i;
108 freqdata[ncfft].i = freqdata[0].i = _mm_set1_ps (0);
110 freqdata[ncfft].i = freqdata[0].i = 0;
113 for (k = 1; k <= ncfft / 2; ++k) {
115 fpnk.r = st->tmpbuf[ncfft - k].r;
116 fpnk.i = -st->tmpbuf[ncfft - k].i;
120 C_ADD (f1k, fpk, fpnk);
121 C_SUB (f2k, fpk, fpnk);
122 C_MUL (tw, f2k, st->super_twiddles[k - 1]);
124 freqdata[k].r = HALF_OF (f1k.r + tw.r);
125 freqdata[k].i = HALF_OF (f1k.i + tw.i);
126 freqdata[ncfft - k].r = HALF_OF (f1k.r - tw.r);
127 freqdata[ncfft - k].i = HALF_OF (tw.i - f1k.i);
132 kiss_fftri_s16 (kiss_fftr_s16_cfg st, const kiss_fft_s16_cpx * freqdata,
133 kiss_fft_s16_scalar * timedata)
135 /* input buffer timedata is stored row-wise */
138 if (st->substate->inverse == 0) {
139 fprintf (stderr, "kiss fft usage error: improper alloc\n");
143 ncfft = st->substate->nfft;
145 st->tmpbuf[0].r = freqdata[0].r + freqdata[ncfft].r;
146 st->tmpbuf[0].i = freqdata[0].r - freqdata[ncfft].r;
147 C_FIXDIV (st->tmpbuf[0], 2);
149 for (k = 1; k <= ncfft / 2; ++k) {
150 kiss_fft_s16_cpx fk, fnkc, fek, fok, tmp;
153 fnkc.r = freqdata[ncfft - k].r;
154 fnkc.i = -freqdata[ncfft - k].i;
158 C_ADD (fek, fk, fnkc);
159 C_SUB (tmp, fk, fnkc);
160 C_MUL (fok, tmp, st->super_twiddles[k - 1]);
161 C_ADD (st->tmpbuf[k], fek, fok);
162 C_SUB (st->tmpbuf[ncfft - k], fek, fok);
164 st->tmpbuf[ncfft - k].i *= _mm_set1_ps (-1.0);
166 st->tmpbuf[ncfft - k].i *= -1;
169 kiss_fft_s16 (st->substate, st->tmpbuf, (kiss_fft_s16_cpx *) timedata);