Eli Hughes / CMSIS_DSP_401

V4.0.1 of the ARM CMSIS DSP libraries. Note that arm_bitreversal2.s, arm_cfft_f32.c and arm_rfft_fast_f32.c had to be removed. arm_bitreversal2.s will not assemble with the online tools. So, the fast f32 FFT functions are not yet available. All the other FFT functions are available.

Dependents:   MPU9150_Example fir_f32 fir_f32 MPU9150_nucleo_noni2cdev ... more

TransformFunctions/arm_cfft_radix8_f32.c@0:3d9c67d97d6f, 2014-07-28 (annotated)

Committer:
emh203
Date:
Mon Jul 28 15:03:15 2014 +0000
Revision:
0:3d9c67d97d6f
1st working commit.   Had to remove arm_bitreversal2.s     arm_cfft_f32.c and arm_rfft_fast_f32.c.    The .s will not assemble.      For now I removed these functions so we could at least have a library for the other functions.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
emh203 0:3d9c67d97d6f 1 /* ----------------------------------------------------------------------
emh203 0:3d9c67d97d6f 2 * Copyright (C) 2010-2014 ARM Limited. All rights reserved.
emh203 0:3d9c67d97d6f 3 *
emh203 0:3d9c67d97d6f 4 * $Date: 12. March 2014
emh203 0:3d9c67d97d6f 5 * $Revision: V1.4.3
emh203 0:3d9c67d97d6f 6 *
emh203 0:3d9c67d97d6f 7 * Project: CMSIS DSP Library
emh203 0:3d9c67d97d6f 8 * Title: arm_cfft_radix8_f32.c
emh203 0:3d9c67d97d6f 9 *
emh203 0:3d9c67d97d6f 10 * Description: Radix-8 Decimation in Frequency CFFT & CIFFT Floating point processing function
emh203 0:3d9c67d97d6f 11 *
emh203 0:3d9c67d97d6f 12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
emh203 0:3d9c67d97d6f 13 *
emh203 0:3d9c67d97d6f 14 * Redistribution and use in source and binary forms, with or without
emh203 0:3d9c67d97d6f 15 * modification, are permitted provided that the following conditions
emh203 0:3d9c67d97d6f 16 * are met:
emh203 0:3d9c67d97d6f 17 * - Redistributions of source code must retain the above copyright
emh203 0:3d9c67d97d6f 18 * notice, this list of conditions and the following disclaimer.
emh203 0:3d9c67d97d6f 19 * - Redistributions in binary form must reproduce the above copyright
emh203 0:3d9c67d97d6f 20 * notice, this list of conditions and the following disclaimer in
emh203 0:3d9c67d97d6f 21 * the documentation and/or other materials provided with the
emh203 0:3d9c67d97d6f 22 * distribution.
emh203 0:3d9c67d97d6f 23 * - Neither the name of ARM LIMITED nor the names of its contributors
emh203 0:3d9c67d97d6f 24 * may be used to endorse or promote products derived from this
emh203 0:3d9c67d97d6f 25 * software without specific prior written permission.
emh203 0:3d9c67d97d6f 26 *
emh203 0:3d9c67d97d6f 27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
emh203 0:3d9c67d97d6f 28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
emh203 0:3d9c67d97d6f 29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
emh203 0:3d9c67d97d6f 30 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
emh203 0:3d9c67d97d6f 31 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
emh203 0:3d9c67d97d6f 32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
emh203 0:3d9c67d97d6f 33 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
emh203 0:3d9c67d97d6f 34 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
emh203 0:3d9c67d97d6f 35 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
emh203 0:3d9c67d97d6f 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
emh203 0:3d9c67d97d6f 37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
emh203 0:3d9c67d97d6f 38 * POSSIBILITY OF SUCH DAMAGE.
emh203 0:3d9c67d97d6f 39 * -------------------------------------------------------------------- */
emh203 0:3d9c67d97d6f 40
emh203 0:3d9c67d97d6f 41 #include "arm_math.h"
emh203 0:3d9c67d97d6f 42
emh203 0:3d9c67d97d6f 43 /**
emh203 0:3d9c67d97d6f 44 * @ingroup groupTransforms
emh203 0:3d9c67d97d6f 45 */
emh203 0:3d9c67d97d6f 46
emh203 0:3d9c67d97d6f 47 /**
emh203 0:3d9c67d97d6f 48 * @defgroup Radix8_CFFT_CIFFT Radix-8 Complex FFT Functions
emh203 0:3d9c67d97d6f 49 *
emh203 0:3d9c67d97d6f 50 * \par
emh203 0:3d9c67d97d6f 51 * Complex Fast Fourier Transform(CFFT) and Complex Inverse Fast Fourier Transform(CIFFT) is an efficient algorithm to compute Discrete Fourier Transform(DFT) and Inverse Discrete Fourier Transform(IDFT).
emh203 0:3d9c67d97d6f 52 * Computational complexity of CFFT reduces drastically when compared to DFT.
emh203 0:3d9c67d97d6f 53 * \par
emh203 0:3d9c67d97d6f 54 * This set of functions implements CFFT/CIFFT
emh203 0:3d9c67d97d6f 55 * for floating-point data types. The functions operates on in-place buffer which uses same buffer for input and output.
emh203 0:3d9c67d97d6f 56 * Complex input is stored in input buffer in an interleaved fashion.
emh203 0:3d9c67d97d6f 57 *
emh203 0:3d9c67d97d6f 58 * \par
emh203 0:3d9c67d97d6f 59 * The functions operate on blocks of input and output data and each call to the function processes
emh203 0:3d9c67d97d6f 60 * <code>2*fftLen</code> samples through the transform. <code>pSrc</code> points to In-place arrays containing <code>2*fftLen</code> values.
emh203 0:3d9c67d97d6f 61 * \par
emh203 0:3d9c67d97d6f 62 * The <code>pSrc</code> points to the array of in-place buffer of size <code>2*fftLen</code> and inputs and outputs are stored in an interleaved fashion as shown below.
emh203 0:3d9c67d97d6f 63 * <pre> {real[0], imag[0], real[1], imag[1],..} </pre>
emh203 0:3d9c67d97d6f 64 *
emh203 0:3d9c67d97d6f 65 * \par Lengths supported by the transform:
emh203 0:3d9c67d97d6f 66 * \par
emh203 0:3d9c67d97d6f 67 * Internally, the function utilize a Radix-8 decimation in frequency(DIF) algorithm
emh203 0:3d9c67d97d6f 68 * and the size of the FFT supported are of the lengths [ 64, 512, 4096].
emh203 0:3d9c67d97d6f 69 *
emh203 0:3d9c67d97d6f 70 *
emh203 0:3d9c67d97d6f 71 * \par Algorithm:
emh203 0:3d9c67d97d6f 72 *
emh203 0:3d9c67d97d6f 73 * <b>Complex Fast Fourier Transform:</b>
emh203 0:3d9c67d97d6f 74 * \par
emh203 0:3d9c67d97d6f 75 * Input real and imaginary data:
emh203 0:3d9c67d97d6f 76 * <pre>
emh203 0:3d9c67d97d6f 77 * x(n) = xa + j * ya
emh203 0:3d9c67d97d6f 78 * x(n+N/4 ) = xb + j * yb
emh203 0:3d9c67d97d6f 79 * x(n+N/2 ) = xc + j * yc
emh203 0:3d9c67d97d6f 80 * x(n+3N 4) = xd + j * yd
emh203 0:3d9c67d97d6f 81 * </pre>
emh203 0:3d9c67d97d6f 82 * where N is length of FFT
emh203 0:3d9c67d97d6f 83 * \par
emh203 0:3d9c67d97d6f 84 * Output real and imaginary data:
emh203 0:3d9c67d97d6f 85 * <pre>
emh203 0:3d9c67d97d6f 86 * X(4r) = xa'+ j * ya'
emh203 0:3d9c67d97d6f 87 * X(4r+1) = xb'+ j * yb'
emh203 0:3d9c67d97d6f 88 * X(4r+2) = xc'+ j * yc'
emh203 0:3d9c67d97d6f 89 * X(4r+3) = xd'+ j * yd'
emh203 0:3d9c67d97d6f 90 * </pre>
emh203 0:3d9c67d97d6f 91 * \par
emh203 0:3d9c67d97d6f 92 * Twiddle factors for Radix-8 FFT:
emh203 0:3d9c67d97d6f 93 * <pre>
emh203 0:3d9c67d97d6f 94 * Wn = co1 + j * (- si1)
emh203 0:3d9c67d97d6f 95 * W2n = co2 + j * (- si2)
emh203 0:3d9c67d97d6f 96 * W3n = co3 + j * (- si3)
emh203 0:3d9c67d97d6f 97 * </pre>
emh203 0:3d9c67d97d6f 98 *
emh203 0:3d9c67d97d6f 99 * \par
emh203 0:3d9c67d97d6f 100 * \image html CFFT.gif "Radix-8 Decimation-in Frequency Complex Fast Fourier Transform"
emh203 0:3d9c67d97d6f 101 *
emh203 0:3d9c67d97d6f 102 * \par
emh203 0:3d9c67d97d6f 103 * Output from Radix-8 CFFT Results in Digit reversal order. Interchange middle two branches of every butterfly results in Bit reversed output.
emh203 0:3d9c67d97d6f 104 * \par
emh203 0:3d9c67d97d6f 105 * <b> Butterfly CFFT equations:</b>
emh203 0:3d9c67d97d6f 106 * <pre>
emh203 0:3d9c67d97d6f 107 * xa' = xa + xb + xc + xd
emh203 0:3d9c67d97d6f 108 * ya' = ya + yb + yc + yd
emh203 0:3d9c67d97d6f 109 * xc' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1)
emh203 0:3d9c67d97d6f 110 * yc' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1)
emh203 0:3d9c67d97d6f 111 * xb' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2)
emh203 0:3d9c67d97d6f 112 * yb' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2)
emh203 0:3d9c67d97d6f 113 * xd' = (xa-yb-xc+yd)* co3 + (ya+xb-yc-xd)* (si3)
emh203 0:3d9c67d97d6f 114 * yd' = (ya+xb-yc-xd)* co3 - (xa-yb-xc+yd)* (si3)
emh203 0:3d9c67d97d6f 115 * </pre>
emh203 0:3d9c67d97d6f 116 *
emh203 0:3d9c67d97d6f 117 * \par
emh203 0:3d9c67d97d6f 118 * where <code>fftLen</code> length of CFFT/CIFFT; <code>ifftFlag</code> Flag for selection of CFFT or CIFFT(Set ifftFlag to calculate CIFFT otherwise calculates CFFT);
emh203 0:3d9c67d97d6f 119 * <code>bitReverseFlag</code> Flag for selection of output order(Set bitReverseFlag to output in normal order otherwise output in bit reversed order);
emh203 0:3d9c67d97d6f 120 * <code>pTwiddle</code>points to array of twiddle coefficients; <code>pBitRevTable</code> points to the array of bit reversal table.
emh203 0:3d9c67d97d6f 121 * <code>twidCoefModifier</code> modifier for twiddle factor table which supports all FFT lengths with same table;
emh203 0:3d9c67d97d6f 122 * <code>pBitRevTable</code> modifier for bit reversal table which supports all FFT lengths with same table.
emh203 0:3d9c67d97d6f 123 * <code>onebyfftLen</code> value of 1/fftLen to calculate CIFFT;
emh203 0:3d9c67d97d6f 124 *
emh203 0:3d9c67d97d6f 125 * \par Fixed-Point Behavior
emh203 0:3d9c67d97d6f 126 * Care must be taken when using the fixed-point versions of the CFFT/CIFFT function.
emh203 0:3d9c67d97d6f 127 * Refer to the function specific documentation below for usage guidelines.
emh203 0:3d9c67d97d6f 128 */
emh203 0:3d9c67d97d6f 129
emh203 0:3d9c67d97d6f 130
emh203 0:3d9c67d97d6f 131 /*
emh203 0:3d9c67d97d6f 132 * @brief Core function for the floating-point CFFT butterfly process.
emh203 0:3d9c67d97d6f 133 * @param[in, out] *pSrc points to the in-place buffer of floating-point data type.
emh203 0:3d9c67d97d6f 134 * @param[in] fftLen length of the FFT.
emh203 0:3d9c67d97d6f 135 * @param[in] *pCoef points to the twiddle coefficient buffer.
emh203 0:3d9c67d97d6f 136 * @param[in] twidCoefModifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table.
emh203 0:3d9c67d97d6f 137 * @return none.
emh203 0:3d9c67d97d6f 138 */
emh203 0:3d9c67d97d6f 139
emh203 0:3d9c67d97d6f 140 void arm_radix8_butterfly_f32(
emh203 0:3d9c67d97d6f 141 float32_t * pSrc,
emh203 0:3d9c67d97d6f 142 uint16_t fftLen,
emh203 0:3d9c67d97d6f 143 const float32_t * pCoef,
emh203 0:3d9c67d97d6f 144 uint16_t twidCoefModifier)
emh203 0:3d9c67d97d6f 145 {
emh203 0:3d9c67d97d6f 146 uint32_t ia1, ia2, ia3, ia4, ia5, ia6, ia7;
emh203 0:3d9c67d97d6f 147 uint32_t i1, i2, i3, i4, i5, i6, i7, i8;
emh203 0:3d9c67d97d6f 148 uint32_t id;
emh203 0:3d9c67d97d6f 149 uint32_t n1, n2, j;
emh203 0:3d9c67d97d6f 150
emh203 0:3d9c67d97d6f 151 float32_t r1, r2, r3, r4, r5, r6, r7, r8;
emh203 0:3d9c67d97d6f 152 float32_t t1, t2;
emh203 0:3d9c67d97d6f 153 float32_t s1, s2, s3, s4, s5, s6, s7, s8;
emh203 0:3d9c67d97d6f 154 float32_t p1, p2, p3, p4;
emh203 0:3d9c67d97d6f 155 float32_t co2, co3, co4, co5, co6, co7, co8;
emh203 0:3d9c67d97d6f 156 float32_t si2, si3, si4, si5, si6, si7, si8;
emh203 0:3d9c67d97d6f 157 const float32_t C81 = 0.70710678118f;
emh203 0:3d9c67d97d6f 158
emh203 0:3d9c67d97d6f 159 n2 = fftLen;
emh203 0:3d9c67d97d6f 160
emh203 0:3d9c67d97d6f 161 do
emh203 0:3d9c67d97d6f 162 {
emh203 0:3d9c67d97d6f 163 n1 = n2;
emh203 0:3d9c67d97d6f 164 n2 = n2 >> 3;
emh203 0:3d9c67d97d6f 165 i1 = 0;
emh203 0:3d9c67d97d6f 166
emh203 0:3d9c67d97d6f 167 do
emh203 0:3d9c67d97d6f 168 {
emh203 0:3d9c67d97d6f 169 i2 = i1 + n2;
emh203 0:3d9c67d97d6f 170 i3 = i2 + n2;
emh203 0:3d9c67d97d6f 171 i4 = i3 + n2;
emh203 0:3d9c67d97d6f 172 i5 = i4 + n2;
emh203 0:3d9c67d97d6f 173 i6 = i5 + n2;
emh203 0:3d9c67d97d6f 174 i7 = i6 + n2;
emh203 0:3d9c67d97d6f 175 i8 = i7 + n2;
emh203 0:3d9c67d97d6f 176 r1 = pSrc[2 * i1] + pSrc[2 * i5];
emh203 0:3d9c67d97d6f 177 r5 = pSrc[2 * i1] - pSrc[2 * i5];
emh203 0:3d9c67d97d6f 178 r2 = pSrc[2 * i2] + pSrc[2 * i6];
emh203 0:3d9c67d97d6f 179 r6 = pSrc[2 * i2] - pSrc[2 * i6];
emh203 0:3d9c67d97d6f 180 r3 = pSrc[2 * i3] + pSrc[2 * i7];
emh203 0:3d9c67d97d6f 181 r7 = pSrc[2 * i3] - pSrc[2 * i7];
emh203 0:3d9c67d97d6f 182 r4 = pSrc[2 * i4] + pSrc[2 * i8];
emh203 0:3d9c67d97d6f 183 r8 = pSrc[2 * i4] - pSrc[2 * i8];
emh203 0:3d9c67d97d6f 184 t1 = r1 - r3;
emh203 0:3d9c67d97d6f 185 r1 = r1 + r3;
emh203 0:3d9c67d97d6f 186 r3 = r2 - r4;
emh203 0:3d9c67d97d6f 187 r2 = r2 + r4;
emh203 0:3d9c67d97d6f 188 pSrc[2 * i1] = r1 + r2;
emh203 0:3d9c67d97d6f 189 pSrc[2 * i5] = r1 - r2;
emh203 0:3d9c67d97d6f 190 r1 = pSrc[2 * i1 + 1] + pSrc[2 * i5 + 1];
emh203 0:3d9c67d97d6f 191 s5 = pSrc[2 * i1 + 1] - pSrc[2 * i5 + 1];
emh203 0:3d9c67d97d6f 192 r2 = pSrc[2 * i2 + 1] + pSrc[2 * i6 + 1];
emh203 0:3d9c67d97d6f 193 s6 = pSrc[2 * i2 + 1] - pSrc[2 * i6 + 1];
emh203 0:3d9c67d97d6f 194 s3 = pSrc[2 * i3 + 1] + pSrc[2 * i7 + 1];
emh203 0:3d9c67d97d6f 195 s7 = pSrc[2 * i3 + 1] - pSrc[2 * i7 + 1];
emh203 0:3d9c67d97d6f 196 r4 = pSrc[2 * i4 + 1] + pSrc[2 * i8 + 1];
emh203 0:3d9c67d97d6f 197 s8 = pSrc[2 * i4 + 1] - pSrc[2 * i8 + 1];
emh203 0:3d9c67d97d6f 198 t2 = r1 - s3;
emh203 0:3d9c67d97d6f 199 r1 = r1 + s3;
emh203 0:3d9c67d97d6f 200 s3 = r2 - r4;
emh203 0:3d9c67d97d6f 201 r2 = r2 + r4;
emh203 0:3d9c67d97d6f 202 pSrc[2 * i1 + 1] = r1 + r2;
emh203 0:3d9c67d97d6f 203 pSrc[2 * i5 + 1] = r1 - r2;
emh203 0:3d9c67d97d6f 204 pSrc[2 * i3] = t1 + s3;
emh203 0:3d9c67d97d6f 205 pSrc[2 * i7] = t1 - s3;
emh203 0:3d9c67d97d6f 206 pSrc[2 * i3 + 1] = t2 - r3;
emh203 0:3d9c67d97d6f 207 pSrc[2 * i7 + 1] = t2 + r3;
emh203 0:3d9c67d97d6f 208 r1 = (r6 - r8) * C81;
emh203 0:3d9c67d97d6f 209 r6 = (r6 + r8) * C81;
emh203 0:3d9c67d97d6f 210 r2 = (s6 - s8) * C81;
emh203 0:3d9c67d97d6f 211 s6 = (s6 + s8) * C81;
emh203 0:3d9c67d97d6f 212 t1 = r5 - r1;
emh203 0:3d9c67d97d6f 213 r5 = r5 + r1;
emh203 0:3d9c67d97d6f 214 r8 = r7 - r6;
emh203 0:3d9c67d97d6f 215 r7 = r7 + r6;
emh203 0:3d9c67d97d6f 216 t2 = s5 - r2;
emh203 0:3d9c67d97d6f 217 s5 = s5 + r2;
emh203 0:3d9c67d97d6f 218 s8 = s7 - s6;
emh203 0:3d9c67d97d6f 219 s7 = s7 + s6;
emh203 0:3d9c67d97d6f 220 pSrc[2 * i2] = r5 + s7;
emh203 0:3d9c67d97d6f 221 pSrc[2 * i8] = r5 - s7;
emh203 0:3d9c67d97d6f 222 pSrc[2 * i6] = t1 + s8;
emh203 0:3d9c67d97d6f 223 pSrc[2 * i4] = t1 - s8;
emh203 0:3d9c67d97d6f 224 pSrc[2 * i2 + 1] = s5 - r7;
emh203 0:3d9c67d97d6f 225 pSrc[2 * i8 + 1] = s5 + r7;
emh203 0:3d9c67d97d6f 226 pSrc[2 * i6 + 1] = t2 - r8;
emh203 0:3d9c67d97d6f 227 pSrc[2 * i4 + 1] = t2 + r8;
emh203 0:3d9c67d97d6f 228
emh203 0:3d9c67d97d6f 229 i1 += n1;
emh203 0:3d9c67d97d6f 230 } while(i1 < fftLen);
emh203 0:3d9c67d97d6f 231
emh203 0:3d9c67d97d6f 232 if(n2 < 8)
emh203 0:3d9c67d97d6f 233 break;
emh203 0:3d9c67d97d6f 234
emh203 0:3d9c67d97d6f 235 ia1 = 0;
emh203 0:3d9c67d97d6f 236 j = 1;
emh203 0:3d9c67d97d6f 237
emh203 0:3d9c67d97d6f 238 do
emh203 0:3d9c67d97d6f 239 {
emh203 0:3d9c67d97d6f 240 /* index calculation for the coefficients */
emh203 0:3d9c67d97d6f 241 id = ia1 + twidCoefModifier;
emh203 0:3d9c67d97d6f 242 ia1 = id;
emh203 0:3d9c67d97d6f 243 ia2 = ia1 + id;
emh203 0:3d9c67d97d6f 244 ia3 = ia2 + id;
emh203 0:3d9c67d97d6f 245 ia4 = ia3 + id;
emh203 0:3d9c67d97d6f 246 ia5 = ia4 + id;
emh203 0:3d9c67d97d6f 247 ia6 = ia5 + id;
emh203 0:3d9c67d97d6f 248 ia7 = ia6 + id;
emh203 0:3d9c67d97d6f 249
emh203 0:3d9c67d97d6f 250 co2 = pCoef[2 * ia1];
emh203 0:3d9c67d97d6f 251 co3 = pCoef[2 * ia2];
emh203 0:3d9c67d97d6f 252 co4 = pCoef[2 * ia3];
emh203 0:3d9c67d97d6f 253 co5 = pCoef[2 * ia4];
emh203 0:3d9c67d97d6f 254 co6 = pCoef[2 * ia5];
emh203 0:3d9c67d97d6f 255 co7 = pCoef[2 * ia6];
emh203 0:3d9c67d97d6f 256 co8 = pCoef[2 * ia7];
emh203 0:3d9c67d97d6f 257 si2 = pCoef[2 * ia1 + 1];
emh203 0:3d9c67d97d6f 258 si3 = pCoef[2 * ia2 + 1];
emh203 0:3d9c67d97d6f 259 si4 = pCoef[2 * ia3 + 1];
emh203 0:3d9c67d97d6f 260 si5 = pCoef[2 * ia4 + 1];
emh203 0:3d9c67d97d6f 261 si6 = pCoef[2 * ia5 + 1];
emh203 0:3d9c67d97d6f 262 si7 = pCoef[2 * ia6 + 1];
emh203 0:3d9c67d97d6f 263 si8 = pCoef[2 * ia7 + 1];
emh203 0:3d9c67d97d6f 264
emh203 0:3d9c67d97d6f 265 i1 = j;
emh203 0:3d9c67d97d6f 266
emh203 0:3d9c67d97d6f 267 do
emh203 0:3d9c67d97d6f 268 {
emh203 0:3d9c67d97d6f 269 /* index calculation for the input */
emh203 0:3d9c67d97d6f 270 i2 = i1 + n2;
emh203 0:3d9c67d97d6f 271 i3 = i2 + n2;
emh203 0:3d9c67d97d6f 272 i4 = i3 + n2;
emh203 0:3d9c67d97d6f 273 i5 = i4 + n2;
emh203 0:3d9c67d97d6f 274 i6 = i5 + n2;
emh203 0:3d9c67d97d6f 275 i7 = i6 + n2;
emh203 0:3d9c67d97d6f 276 i8 = i7 + n2;
emh203 0:3d9c67d97d6f 277 r1 = pSrc[2 * i1] + pSrc[2 * i5];
emh203 0:3d9c67d97d6f 278 r5 = pSrc[2 * i1] - pSrc[2 * i5];
emh203 0:3d9c67d97d6f 279 r2 = pSrc[2 * i2] + pSrc[2 * i6];
emh203 0:3d9c67d97d6f 280 r6 = pSrc[2 * i2] - pSrc[2 * i6];
emh203 0:3d9c67d97d6f 281 r3 = pSrc[2 * i3] + pSrc[2 * i7];
emh203 0:3d9c67d97d6f 282 r7 = pSrc[2 * i3] - pSrc[2 * i7];
emh203 0:3d9c67d97d6f 283 r4 = pSrc[2 * i4] + pSrc[2 * i8];
emh203 0:3d9c67d97d6f 284 r8 = pSrc[2 * i4] - pSrc[2 * i8];
emh203 0:3d9c67d97d6f 285 t1 = r1 - r3;
emh203 0:3d9c67d97d6f 286 r1 = r1 + r3;
emh203 0:3d9c67d97d6f 287 r3 = r2 - r4;
emh203 0:3d9c67d97d6f 288 r2 = r2 + r4;
emh203 0:3d9c67d97d6f 289 pSrc[2 * i1] = r1 + r2;
emh203 0:3d9c67d97d6f 290 r2 = r1 - r2;
emh203 0:3d9c67d97d6f 291 s1 = pSrc[2 * i1 + 1] + pSrc[2 * i5 + 1];
emh203 0:3d9c67d97d6f 292 s5 = pSrc[2 * i1 + 1] - pSrc[2 * i5 + 1];
emh203 0:3d9c67d97d6f 293 s2 = pSrc[2 * i2 + 1] + pSrc[2 * i6 + 1];
emh203 0:3d9c67d97d6f 294 s6 = pSrc[2 * i2 + 1] - pSrc[2 * i6 + 1];
emh203 0:3d9c67d97d6f 295 s3 = pSrc[2 * i3 + 1] + pSrc[2 * i7 + 1];
emh203 0:3d9c67d97d6f 296 s7 = pSrc[2 * i3 + 1] - pSrc[2 * i7 + 1];
emh203 0:3d9c67d97d6f 297 s4 = pSrc[2 * i4 + 1] + pSrc[2 * i8 + 1];
emh203 0:3d9c67d97d6f 298 s8 = pSrc[2 * i4 + 1] - pSrc[2 * i8 + 1];
emh203 0:3d9c67d97d6f 299 t2 = s1 - s3;
emh203 0:3d9c67d97d6f 300 s1 = s1 + s3;
emh203 0:3d9c67d97d6f 301 s3 = s2 - s4;
emh203 0:3d9c67d97d6f 302 s2 = s2 + s4;
emh203 0:3d9c67d97d6f 303 r1 = t1 + s3;
emh203 0:3d9c67d97d6f 304 t1 = t1 - s3;
emh203 0:3d9c67d97d6f 305 pSrc[2 * i1 + 1] = s1 + s2;
emh203 0:3d9c67d97d6f 306 s2 = s1 - s2;
emh203 0:3d9c67d97d6f 307 s1 = t2 - r3;
emh203 0:3d9c67d97d6f 308 t2 = t2 + r3;
emh203 0:3d9c67d97d6f 309 p1 = co5 * r2;
emh203 0:3d9c67d97d6f 310 p2 = si5 * s2;
emh203 0:3d9c67d97d6f 311 p3 = co5 * s2;
emh203 0:3d9c67d97d6f 312 p4 = si5 * r2;
emh203 0:3d9c67d97d6f 313 pSrc[2 * i5] = p1 + p2;
emh203 0:3d9c67d97d6f 314 pSrc[2 * i5 + 1] = p3 - p4;
emh203 0:3d9c67d97d6f 315 p1 = co3 * r1;
emh203 0:3d9c67d97d6f 316 p2 = si3 * s1;
emh203 0:3d9c67d97d6f 317 p3 = co3 * s1;
emh203 0:3d9c67d97d6f 318 p4 = si3 * r1;
emh203 0:3d9c67d97d6f 319 pSrc[2 * i3] = p1 + p2;
emh203 0:3d9c67d97d6f 320 pSrc[2 * i3 + 1] = p3 - p4;
emh203 0:3d9c67d97d6f 321 p1 = co7 * t1;
emh203 0:3d9c67d97d6f 322 p2 = si7 * t2;
emh203 0:3d9c67d97d6f 323 p3 = co7 * t2;
emh203 0:3d9c67d97d6f 324 p4 = si7 * t1;
emh203 0:3d9c67d97d6f 325 pSrc[2 * i7] = p1 + p2;
emh203 0:3d9c67d97d6f 326 pSrc[2 * i7 + 1] = p3 - p4;
emh203 0:3d9c67d97d6f 327 r1 = (r6 - r8) * C81;
emh203 0:3d9c67d97d6f 328 r6 = (r6 + r8) * C81;
emh203 0:3d9c67d97d6f 329 s1 = (s6 - s8) * C81;
emh203 0:3d9c67d97d6f 330 s6 = (s6 + s8) * C81;
emh203 0:3d9c67d97d6f 331 t1 = r5 - r1;
emh203 0:3d9c67d97d6f 332 r5 = r5 + r1;
emh203 0:3d9c67d97d6f 333 r8 = r7 - r6;
emh203 0:3d9c67d97d6f 334 r7 = r7 + r6;
emh203 0:3d9c67d97d6f 335 t2 = s5 - s1;
emh203 0:3d9c67d97d6f 336 s5 = s5 + s1;
emh203 0:3d9c67d97d6f 337 s8 = s7 - s6;
emh203 0:3d9c67d97d6f 338 s7 = s7 + s6;
emh203 0:3d9c67d97d6f 339 r1 = r5 + s7;
emh203 0:3d9c67d97d6f 340 r5 = r5 - s7;
emh203 0:3d9c67d97d6f 341 r6 = t1 + s8;
emh203 0:3d9c67d97d6f 342 t1 = t1 - s8;
emh203 0:3d9c67d97d6f 343 s1 = s5 - r7;
emh203 0:3d9c67d97d6f 344 s5 = s5 + r7;
emh203 0:3d9c67d97d6f 345 s6 = t2 - r8;
emh203 0:3d9c67d97d6f 346 t2 = t2 + r8;
emh203 0:3d9c67d97d6f 347 p1 = co2 * r1;
emh203 0:3d9c67d97d6f 348 p2 = si2 * s1;
emh203 0:3d9c67d97d6f 349 p3 = co2 * s1;
emh203 0:3d9c67d97d6f 350 p4 = si2 * r1;
emh203 0:3d9c67d97d6f 351 pSrc[2 * i2] = p1 + p2;
emh203 0:3d9c67d97d6f 352 pSrc[2 * i2 + 1] = p3 - p4;
emh203 0:3d9c67d97d6f 353 p1 = co8 * r5;
emh203 0:3d9c67d97d6f 354 p2 = si8 * s5;
emh203 0:3d9c67d97d6f 355 p3 = co8 * s5;
emh203 0:3d9c67d97d6f 356 p4 = si8 * r5;
emh203 0:3d9c67d97d6f 357 pSrc[2 * i8] = p1 + p2;
emh203 0:3d9c67d97d6f 358 pSrc[2 * i8 + 1] = p3 - p4;
emh203 0:3d9c67d97d6f 359 p1 = co6 * r6;
emh203 0:3d9c67d97d6f 360 p2 = si6 * s6;
emh203 0:3d9c67d97d6f 361 p3 = co6 * s6;
emh203 0:3d9c67d97d6f 362 p4 = si6 * r6;
emh203 0:3d9c67d97d6f 363 pSrc[2 * i6] = p1 + p2;
emh203 0:3d9c67d97d6f 364 pSrc[2 * i6 + 1] = p3 - p4;
emh203 0:3d9c67d97d6f 365 p1 = co4 * t1;
emh203 0:3d9c67d97d6f 366 p2 = si4 * t2;
emh203 0:3d9c67d97d6f 367 p3 = co4 * t2;
emh203 0:3d9c67d97d6f 368 p4 = si4 * t1;
emh203 0:3d9c67d97d6f 369 pSrc[2 * i4] = p1 + p2;
emh203 0:3d9c67d97d6f 370 pSrc[2 * i4 + 1] = p3 - p4;
emh203 0:3d9c67d97d6f 371
emh203 0:3d9c67d97d6f 372 i1 += n1;
emh203 0:3d9c67d97d6f 373 } while(i1 < fftLen);
emh203 0:3d9c67d97d6f 374
emh203 0:3d9c67d97d6f 375 j++;
emh203 0:3d9c67d97d6f 376 } while(j < n2);
emh203 0:3d9c67d97d6f 377
emh203 0:3d9c67d97d6f 378 twidCoefModifier <<= 3;
emh203 0:3d9c67d97d6f 379 } while(n2 > 7);
emh203 0:3d9c67d97d6f 380 }
emh203 0:3d9c67d97d6f 381
emh203 0:3d9c67d97d6f 382 /**
emh203 0:3d9c67d97d6f 383 * @} end of Radix8_CFFT_CIFFT group
emh203 0:3d9c67d97d6f 384 */