Mercurial > hg > peckfft

annotate peck_fft.c @ 0:723f588b82ac

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
import
author Peter Meerwald <p.meerwald@bct-electronic.com>
date Fri, 16 Sep 2011 12:53:08 +0200
parents
children cfec79393811
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
0
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
1 /*
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
2 Copyright (c) 2003-2010, Mark Borgerding
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
3
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
4 All rights reserved.
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
5
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
6 Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
7
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
8 * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
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.
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
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.
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
11
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
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.
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
13 */
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
14
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
15
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
16 #include "_peck_fft_guts.h"
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
17 /* The guts header contains all the multiplication and addition macros that are defined for
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
18 fixed or floating point complex numbers. It also delares the kf_ internal functions.
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
19 */
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
20
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
21 static void kf_bfly2(
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
22 peck_fft_cpx * Fout,
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
23 const size_t fstride,
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
24 const peck_fft_cfg st,
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
25 int m
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
26 )
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
27 {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
28
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
29 //printf("kf_bfly2\n");
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
30
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
31 peck_fft_cpx * Fout2;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
32 peck_fft_cpx * tw1 = st->twiddles;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
33 peck_fft_cpx t;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
34 Fout2 = Fout + m;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
35 do{
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
36 C_FIXDIV(*Fout,2); C_FIXDIV(*Fout2,2);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
37
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
38 C_MUL (t, *Fout2 , *tw1);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
39 tw1 += fstride;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
40 C_SUB( *Fout2 , *Fout , t );
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
41 C_ADDTO( *Fout , t );
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
42 ++Fout2;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
43 ++Fout;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
44 }while (--m);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
45 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
46
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
47 static void kf_bfly4(
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
48 peck_fft_cpx * Fout,
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
49 const size_t fstride,
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
50 const peck_fft_cfg st,
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
51 const size_t m
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
52 )
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
53 {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
54 peck_fft_cpx *tw1,*tw2,*tw3;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
55 peck_fft_cpx scratch[6];
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
56 size_t k=m;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
57 const size_t m2=2*m;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
58 const size_t m3=3*m;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
59
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
60 //printf("kf_bfly4\n");
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
61
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
62
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
63 tw3 = tw2 = tw1 = st->twiddles;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
64
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
65 do {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
66 C_FIXDIV(*Fout,4); C_FIXDIV(Fout[m],4); C_FIXDIV(Fout[m2],4); C_FIXDIV(Fout[m3],4);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
67
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
68 C_MUL(scratch[0],Fout[m] , *tw1 );
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
69 C_MUL(scratch[1],Fout[m2] , *tw2 );
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
70 C_MUL(scratch[2],Fout[m3] , *tw3 );
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
71
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
72 C_SUB( scratch[5] , *Fout, scratch[1] );
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
73 C_ADDTO(*Fout, scratch[1]);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
74 C_ADD( scratch[3] , scratch[0] , scratch[2] );
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
75 C_SUB( scratch[4] , scratch[0] , scratch[2] );
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
76 C_SUB( Fout[m2], *Fout, scratch[3] );
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
77 tw1 += fstride;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
78 tw2 += fstride*2;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
79 tw3 += fstride*3;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
80 C_ADDTO( *Fout , scratch[3] );
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
81
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
82 if(st->inverse) {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
83 Fout[m].r = scratch[5].r - scratch[4].i;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
84 Fout[m].i = scratch[5].i + scratch[4].r;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
85 Fout[m3].r = scratch[5].r + scratch[4].i;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
86 Fout[m3].i = scratch[5].i - scratch[4].r;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
87 }else{
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
88 Fout[m].r = scratch[5].r + scratch[4].i;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
89 Fout[m].i = scratch[5].i - scratch[4].r;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
90 Fout[m3].r = scratch[5].r - scratch[4].i;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
91 Fout[m3].i = scratch[5].i + scratch[4].r;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
92 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
93 ++Fout;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
94 }while(--k);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
95 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
96
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
97 static void kf_bfly3(
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
98 peck_fft_cpx * Fout,
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
99 const size_t fstride,
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
100 const peck_fft_cfg st,
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
101 size_t m
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
102 )
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
103 {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
104 size_t k=m;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
105 const size_t m2 = 2*m;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
106 peck_fft_cpx *tw1,*tw2;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
107 peck_fft_cpx scratch[5];
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
108 peck_fft_cpx epi3;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
109 epi3 = st->twiddles[fstride*m];
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
110
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
111 printf("kf_bfly3\n");
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
112
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
113
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
114 tw1=tw2=st->twiddles;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
115
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
116 do{
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
117 C_FIXDIV(*Fout,3); C_FIXDIV(Fout[m],3); C_FIXDIV(Fout[m2],3);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
118
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
119 C_MUL(scratch[1],Fout[m] , *tw1);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
120 C_MUL(scratch[2],Fout[m2] , *tw2);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
121
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
122 C_ADD(scratch[3],scratch[1],scratch[2]);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
123 C_SUB(scratch[0],scratch[1],scratch[2]);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
124 tw1 += fstride;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
125 tw2 += fstride*2;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
126
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
127 Fout[m].r = Fout->r - HALF_OF(scratch[3].r);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
128 Fout[m].i = Fout->i - HALF_OF(scratch[3].i);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
129
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
130 C_MULBYSCALAR( scratch[0] , epi3.i );
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
131
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
132 C_ADDTO(*Fout,scratch[3]);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
133
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
134 Fout[m2].r = Fout[m].r + scratch[0].i;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
135 Fout[m2].i = Fout[m].i - scratch[0].r;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
136
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
137 Fout[m].r -= scratch[0].i;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
138 Fout[m].i += scratch[0].r;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
139
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
140 ++Fout;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
141 }while(--k);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
142 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
143
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
144 static void kf_bfly5(
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
145 peck_fft_cpx * Fout,
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
146 const size_t fstride,
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
147 const peck_fft_cfg st,
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
148 int m
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
149 )
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
150 {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
151 peck_fft_cpx *Fout0,*Fout1,*Fout2,*Fout3,*Fout4;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
152 int u;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
153 peck_fft_cpx scratch[13];
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
154 peck_fft_cpx * twiddles = st->twiddles;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
155 peck_fft_cpx *tw;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
156 peck_fft_cpx ya,yb;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
157 ya = twiddles[fstride*m];
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
158 yb = twiddles[fstride*2*m];
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
159
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
160 printf("kf_bfly5\n");
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
161
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
162
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
163 Fout0=Fout;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
164 Fout1=Fout0+m;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
165 Fout2=Fout0+2*m;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
166 Fout3=Fout0+3*m;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
167 Fout4=Fout0+4*m;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
168
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
169 tw=st->twiddles;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
170 for ( u=0; u<m; ++u ) {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
171 C_FIXDIV( *Fout0,5); C_FIXDIV( *Fout1,5); C_FIXDIV( *Fout2,5); C_FIXDIV( *Fout3,5); C_FIXDIV( *Fout4,5);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
172 scratch[0] = *Fout0;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
173
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
174 C_MUL(scratch[1] ,*Fout1, tw[u*fstride]);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
175 C_MUL(scratch[2] ,*Fout2, tw[2*u*fstride]);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
176 C_MUL(scratch[3] ,*Fout3, tw[3*u*fstride]);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
177 C_MUL(scratch[4] ,*Fout4, tw[4*u*fstride]);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
178
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
179 C_ADD( scratch[7],scratch[1],scratch[4]);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
180 C_SUB( scratch[10],scratch[1],scratch[4]);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
181 C_ADD( scratch[8],scratch[2],scratch[3]);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
182 C_SUB( scratch[9],scratch[2],scratch[3]);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
183
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
184 Fout0->r += scratch[7].r + scratch[8].r;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
185 Fout0->i += scratch[7].i + scratch[8].i;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
186
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
187 scratch[5].r = scratch[0].r + S_MUL(scratch[7].r,ya.r) + S_MUL(scratch[8].r,yb.r);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
188 scratch[5].i = scratch[0].i + S_MUL(scratch[7].i,ya.r) + S_MUL(scratch[8].i,yb.r);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
189
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
190 scratch[6].r = S_MUL(scratch[10].i,ya.i) + S_MUL(scratch[9].i,yb.i);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
191 scratch[6].i = -S_MUL(scratch[10].r,ya.i) - S_MUL(scratch[9].r,yb.i);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
192
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
193 C_SUB(*Fout1,scratch[5],scratch[6]);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
194 C_ADD(*Fout4,scratch[5],scratch[6]);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
195
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
196 scratch[11].r = scratch[0].r + S_MUL(scratch[7].r,yb.r) + S_MUL(scratch[8].r,ya.r);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
197 scratch[11].i = scratch[0].i + S_MUL(scratch[7].i,yb.r) + S_MUL(scratch[8].i,ya.r);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
198 scratch[12].r = - S_MUL(scratch[10].i,yb.i) + S_MUL(scratch[9].i,ya.i);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
199 scratch[12].i = S_MUL(scratch[10].r,yb.i) - S_MUL(scratch[9].r,ya.i);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
200
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
201 C_ADD(*Fout2,scratch[11],scratch[12]);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
202 C_SUB(*Fout3,scratch[11],scratch[12]);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
203
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
204 ++Fout0;++Fout1;++Fout2;++Fout3;++Fout4;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
205 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
206 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
207
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
208 /* perform the butterfly for one stage of a mixed radix FFT */
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
209 static void kf_bfly_generic(
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
210 peck_fft_cpx * Fout,
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
211 const size_t fstride,
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
212 const peck_fft_cfg st,
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
213 int m,
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
214 int p
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
215 )
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
216 {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
217 int u,k,q1,q;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
218 peck_fft_cpx * twiddles = st->twiddles;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
219 peck_fft_cpx t;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
220 int Norig = st->nfft;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
221
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
222 printf("kf_bfly_generic\n");
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
223
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
224
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
225 peck_fft_cpx * scratch = (peck_fft_cpx*)PECK_FFT_TMP_ALLOC(sizeof(peck_fft_cpx)*p);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
226
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
227 for ( u=0; u<m; ++u ) {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
228 k=u;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
229 for (q1 = 0; q1 < p; ++q1) {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
230 scratch[q1] = Fout[k];
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
231 C_FIXDIV(scratch[q1], p);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
232 k += m;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
233 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
234
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
235 k=u;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
236 for ( q1=0 ; q1<p ; ++q1 ) {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
237 int twidx=0;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
238 Fout[ k ] = scratch[0];
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
239 for (q=1;q<p;++q ) {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
240 twidx += fstride * k;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
241 if (twidx>=Norig) twidx-=Norig;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
242 C_MUL(t,scratch[q] , twiddles[twidx] );
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
243 C_ADDTO( Fout[ k ] ,t);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
244 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
245 k += m;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
246 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
247 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
248 PECK_FFT_TMP_FREE(scratch);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
249 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
250
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
251 static void kf_work(
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
252 peck_fft_cpx * Fout,
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
253 const peck_fft_cpx * f,
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
254 const size_t fstride,
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
255 int *factors,
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
256 const peck_fft_cfg st) {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
257 peck_fft_cpx *Fout_beg = Fout;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
258 const int p = *factors++; /* the radix */
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
259 const int m = *factors++; /* stage's FFT length / p */
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
260 const peck_fft_cpx *Fout_end = Fout + p*m;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
261
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
262 // printf("kf_work\n");
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
263
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
264 if (m == 1) {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
265 do {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
266 *Fout = *f;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
267 f += fstride;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
268 } while (++Fout != Fout_end);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
269 } else {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
270 do {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
271 // recursive call:
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
272 // DFT of size m*p performed by doing
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
273 // p instances of smaller DFTs of size m,
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
274 // each one takes a decimated version of the input
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
275 kf_work(Fout, f, fstride*p, factors, st);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
276 f += fstride;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
277 } while ((Fout += m) != Fout_end);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
278 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
279
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
280 Fout=Fout_beg;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
281
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
282 // recombine the p smaller DFTs
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
283 switch (p) {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
284 case 2: kf_bfly2(Fout, fstride, st, m); break;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
285 case 3: kf_bfly3(Fout, fstride, st, m); break;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
286 case 4: kf_bfly4(Fout, fstride, st, m); break;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
287 case 5: kf_bfly5(Fout, fstride, st, m); break;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
288 default: kf_bfly_generic(Fout, fstride, st, m, p); break;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
289 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
290 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
291
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
292 /*
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
293 * facbuf is populated by p1, m1, p2, m2, ...
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
294 * where
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
295 * p[i] * m[i] = m[i-1]
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
296 * m0 = n
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
297 */
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
298 static void kf_factor(int n, int * facbuf) {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
299 int p = 4;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
300 float floor_sqrt;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
301 floor_sqrt = floorf(sqrtf(n));
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
302
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
303 /* factor out powers of 4, powers of 2, then any remaining primes */
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
304 do {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
305 while (n % p) {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
306 switch (p) {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
307 case 4: p = 2; break;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
308 case 2: p = 3; break;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
309 default: p += 2; break;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
310 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
311 if (p > floor_sqrt)
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
312 p = n; /* no more factors, skip to end */
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
313 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
314 n /= p;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
315 *facbuf++ = p;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
316 *facbuf++ = n;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
317 } while (n > 1);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
318 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
319
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
320 /*
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
321 * User-callable function to allocate all necessary storage space for the fft.
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
322 * The return value is a contiguous block of memory, allocated with malloc. As such,
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
323 * it can be freed with free(), rather than a peck_fft-specific function.
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
324 */
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
325 peck_fft_cfg peck_fft_alloc(int nfft, int inverse_fft, void * mem, size_t * lenmem) {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
326 peck_fft_cfg st = NULL;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
327 size_t memneeded = sizeof(struct peck_fft_state)
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
328 + sizeof(peck_fft_cpx)*(nfft-1); /* twiddle factors */
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
329
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
330 if (lenmem == NULL) {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
331 st = ( peck_fft_cfg)PECK_FFT_MALLOC(memneeded);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
332 } else {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
333 if (mem != NULL && *lenmem >= memneeded)
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
334 st = (peck_fft_cfg)mem;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
335 *lenmem = memneeded;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
336 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
337
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
338 if (st) {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
339 int i;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
340 st->nfft=nfft;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
341 st->inverse = inverse_fft;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
342
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
343 for (i = 0; i < nfft; ++i) {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
344 const float pi = 3.14159265359f;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
345 float phase = -2*pi*i / nfft;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
346 if (st->inverse)
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
347 phase *= -1;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
348 kf_cexp(st->twiddles+i, phase);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
349 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
350
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
351 kf_factor(nfft, st->factors);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
352 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
353 return st;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
354 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
355
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
356 void peck_fft(peck_fft_cfg cfg, const peck_fft_cpx *fin, peck_fft_cpx *fout) {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
357 kf_work(fout, fin, 1, cfg->factors, cfg);
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
358 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
359
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
360 void peck_fft_cleanup(void) {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
361 /* nothing needed any more */
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
362 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
363
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
364 int peck_fft_next_fast_size(int n) {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
365 while (1) {
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
366 int m = n;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
367 while ((m % 2) == 0) m /= 2;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
368 while ((m % 3) == 0) m /= 3;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
369 while ((m % 5) == 0) m /= 5;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
370 if (m <= 1)
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
371 break; /* n is completely factorable by twos, threes, and fives */
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
372 n++;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
373 }
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
374 return n;
Peter Meerwald <p.meerwald@bct-electronic.com>
parents:
diff changeset
375 }

Repositories maintained by Peter Meerwald, pmeerw@pmeerw.net.