summaryrefslogtreecommitdiffstats
path: root/libFDK/src/arm/fft_rad2_arm.cpp
blob: f40961a3909fc31b66e4697d52eb12e2e7dbc010 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
/***************************  Fraunhofer IIS FDK Tools  **********************

                        (C) Copyright Fraunhofer IIS (2005)
                               All Rights Reserved

    Please be advised that this software and/or program delivery is
    Confidential Information of Fraunhofer and subject to and covered by the

    Fraunhofer IIS Software Evaluation Agreement
    between Google Inc. and  Fraunhofer
    effective and in full force since March 1, 2012.

    You may use this software and/or program only under the terms and
    conditions described in the above mentioned Fraunhofer IIS Software
    Evaluation Agreement. Any other and/or further use requires a separate agreement.


   $Id$
   Author(s):
   Description: dit_fft ARM assembler replacements.

   This software and/or program is protected by copyright law and international
   treaties. Any reproduction or distribution of this software and/or program,
   or any portion of it, may result in severe civil and criminal penalties, and
   will be prosecuted to the maximum extent possible under law.

******************************************************************************/

/* NEON optimized FFT currently builds only with RVCT toolchain */

#ifndef FUNCTION_dit_fft

/* If dit_fft was not yet defined by ARM-Cortex ... */

#if defined(SINETABLE_16BIT)

#define FUNCTION_dit_fft

/*****************************************************************************

   date:   28.07.2005   srl

   Contents/description: dit-tukey-FFT-algorithm

******************************************************************************/

#if defined(FUNCTION_dit_fft)


void dit_fft(FIXP_DBL *x, const INT ldn, const FIXP_STP *trigdata, const INT trigDataSize)
{
    const INT n=1<<ldn;
    INT i;

    scramble(x,n);
    /*
     * 1+2 stage radix 4
     */

    for (i=0;i<n*2;i+=8)
    {
      FIXP_DBL a00, a10, a20, a30;
      a00 = (x[i + 0] + x[i + 2])>>1;  /* Re A + Re B */
      a10 = (x[i + 4] + x[i + 6])>>1;  /* Re C + Re D */
      a20 = (x[i + 1] + x[i + 3])>>1;  /* Im A + Im B */
      a30 = (x[i + 5] + x[i + 7])>>1;  /* Im C + Im D */

      x[i + 0] = a00 + a10;       /* Re A' = Re A + Re B + Re C + Re D */
      x[i + 4] = a00 - a10;       /* Re C' = Re A + Re B - Re C - Re D */
      x[i + 1] = a20 + a30;       /* Im A' = Im A + Im B + Im C + Im D */
      x[i + 5] = a20 - a30;       /* Im C' = Im A + Im B - Im C - Im D */

      a00 = a00 - x[i + 2];       /* Re A - Re B */
      a10 = a10 - x[i + 6];       /* Re C - Re D */
      a20 = a20 - x[i + 3];       /* Im A - Im B */
      a30 = a30 - x[i + 7];       /* Im C - Im D */

      x[i + 2] = a00 + a30;       /* Re B' = Re A - Re B + Im C - Im D */
      x[i + 6] = a00 - a30;       /* Re D' = Re A - Re B - Im C + Im D */
      x[i + 3] = a20 - a10;       /* Im B' = Im A - Im B - Re C + Re D */
      x[i + 7] = a20 + a10;       /* Im D' = Im A - Im B + Re C - Re D */
    }

    INT mh = 1 << 1;
    INT ldm = ldn - 2;
    INT trigstep = trigDataSize;

    do
    {
        const FIXP_STP *pTrigData = trigdata;
        INT j;

        mh <<= 1;
        trigstep >>= 1;

        FDK_ASSERT(trigstep > 0);

        /* Do first iteration with c=1.0 and s=0.0 separately to avoid loosing to much precision.
           Beware: The impact on the overal FFT precision is rather large. */
        {
            FIXP_DBL *xt1 = x;
            int r = n;

            do {
                FIXP_DBL *xt2 = xt1 + (mh<<1);
                /*
                FIXP_DBL *xt1 = x+ ((r)<<1);
                FIXP_DBL *xt2 = xt1 + (mh<<1);
                */
                FIXP_DBL vr,vi,ur,ui;                 

                //cplxMultDiv2(&vi, &vr, x[t2+1], x[t2], (FIXP_SGL)1.0, (FIXP_SGL)0.0);
                vi = xt2[1]>>1;
                vr = xt2[0]>>1;

                ur = xt1[0]>>1;
                ui = xt1[1]>>1;

                xt1[0] = ur+vr;
                xt1[1] = ui+vi;

                xt2[0] = ur-vr;
                xt2[1] = ui-vi;

                xt1 += mh;
                xt2 += mh;

                //cplxMultDiv2(&vr, &vi, x[t2+1], x[t2], (FIXP_SGL)1.0, (FIXP_SGL)0.0);
                vr = xt2[1]>>1;
                vi = xt2[0]>>1;

                ur = xt1[0]>>1;
                ui = xt1[1]>>1;

                xt1[0] = ur+vr;
                xt1[1] = ui-vi;

                xt2[0] = ur-vr;
                xt2[1] = ui+vi;

                xt1 = xt2 + mh;
            } while ((r=r-(mh<<1)) != 0);
        }
        for(j=4; j<mh; j+=4)
        {
            FIXP_DBL *xt1 = x + (j>>1);
            FIXP_SPK cs;
            int r = n;

            pTrigData += trigstep;
            cs = *pTrigData;

            do
            {
                FIXP_DBL *xt2 = xt1 + (mh<<1);
                FIXP_DBL vr,vi,ur,ui;

                cplxMultDiv2(&vi, &vr, xt2[1], xt2[0], cs);

                ur = xt1[0]>>1;
                ui = xt1[1]>>1;

                xt1[0] = ur+vr;
                xt1[1] = ui+vi;

                xt2[0] = ur-vr;
                xt2[1] = ui-vi;

                xt1 += mh;
                xt2 += mh;

                cplxMultDiv2(&vr, &vi, xt2[1], xt2[0], cs);

                ur = xt1[0]>>1;
                ui = xt1[1]>>1;

                xt1[0] = ur+vr;
                xt1[1] = ui-vi;

                xt2[0] = ur-vr;
                xt2[1] = ui+vi;

                /* Same as above but for t1,t2 with j>mh/4 and thus cs swapped */
                xt1 = xt1 - (j);
                xt2 = xt1 + (mh<<1);

                cplxMultDiv2(&vi, &vr, xt2[0], xt2[1], cs);

                ur = xt1[0]>>1;
                ui = xt1[1]>>1;

                xt1[0] = ur+vr;
                xt1[1] = ui-vi;

                xt2[0] = ur-vr;
                xt2[1] = ui+vi;

                xt1 += mh;
                xt2 += mh;

                cplxMultDiv2(&vr, &vi, xt2[0], xt2[1], cs);

                ur = xt1[0]>>1;
                ui = xt1[1]>>1;

                xt1[0] = ur-vr;
                xt1[1] = ui-vi;

                xt2[0] = ur+vr;
                xt2[1] = ui+vi;

                xt1 = xt2 + (j);
            }  while ((r=r-(mh<<1)) != 0);
        }
        {
            FIXP_DBL *xt1 = x + (mh>>1);
            int r = n;

            do
            {
                FIXP_DBL *xt2 = xt1 + (mh<<1);
                FIXP_DBL vr,vi,ur,ui;

                cplxMultDiv2(&vi, &vr, xt2[1], xt2[0], STC(0x5a82799a), STC(0x5a82799a));

                ur = xt1[0]>>1;
                ui = xt1[1]>>1;

                xt1[0] = ur+vr;
                xt1[1] = ui+vi;

                xt2[0] = ur-vr;
                xt2[1] = ui-vi;

                xt1 += mh;
                xt2 += mh;

                cplxMultDiv2(&vr, &vi, xt2[1], xt2[0], STC(0x5a82799a), STC(0x5a82799a));

                ur = xt1[0]>>1;
                ui = xt1[1]>>1;

                xt1[0] = ur+vr;
                xt1[1] = ui-vi;

                xt2[0] = ur-vr;
                xt2[1] = ui+vi;

                xt1 = xt2 + mh;
            }  while ((r=r-(mh<<1)) != 0);
        }
    } while (--ldm != 0);
}

#endif /* if defined(FUNCTION_dit_fft)  */

#endif /* if defined(SINETABLE_16BIT) */

#endif /* ifndef FUNCTION_dit_fft */