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CMSIS DSP library

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cmsis_dsp/TransformFunctions/arm_cfft_radix2_f32.c@3:7a284390b0ce, 2013-11-08 (annotated)

Committer:
mbed_official
Date:
Fri Nov 08 13:45:10 2013 +0000
Revision:
3:7a284390b0ce
Parent:
2:da51fb522205
Child:
5:3762170b6d4d
Synchronized with git revision e69956aba2f68a2a26ac26b051f8d349deaa1ce8

Who changed what in which revision?

UserRevisionLine numberNew contents of line
emilmont 1:fdd22bb7aa52 1 /* ----------------------------------------------------------------------
mbed_official 3:7a284390b0ce 2 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.
emilmont 1:fdd22bb7aa52 3 *
mbed_official 3:7a284390b0ce 4 * $Date: 17. January 2013
mbed_official 3:7a284390b0ce 5 * $Revision: V1.4.1
emilmont 1:fdd22bb7aa52 6 *
emilmont 2:da51fb522205 7 * Project: CMSIS DSP Library
emilmont 2:da51fb522205 8 * Title: arm_cfft_radix2_f32.c
emilmont 1:fdd22bb7aa52 9 *
emilmont 2:da51fb522205 10 * Description: Radix-2 Decimation in Frequency CFFT & CIFFT Floating point processing function
emilmont 1:fdd22bb7aa52 11 *
emilmont 1:fdd22bb7aa52 12 *
emilmont 1:fdd22bb7aa52 13 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
emilmont 1:fdd22bb7aa52 14 *
mbed_official 3:7a284390b0ce 15 * Redistribution and use in source and binary forms, with or without
mbed_official 3:7a284390b0ce 16 * modification, are permitted provided that the following conditions
mbed_official 3:7a284390b0ce 17 * are met:
mbed_official 3:7a284390b0ce 18 * - Redistributions of source code must retain the above copyright
mbed_official 3:7a284390b0ce 19 * notice, this list of conditions and the following disclaimer.
mbed_official 3:7a284390b0ce 20 * - Redistributions in binary form must reproduce the above copyright
mbed_official 3:7a284390b0ce 21 * notice, this list of conditions and the following disclaimer in
mbed_official 3:7a284390b0ce 22 * the documentation and/or other materials provided with the
mbed_official 3:7a284390b0ce 23 * distribution.
mbed_official 3:7a284390b0ce 24 * - Neither the name of ARM LIMITED nor the names of its contributors
mbed_official 3:7a284390b0ce 25 * may be used to endorse or promote products derived from this
mbed_official 3:7a284390b0ce 26 * software without specific prior written permission.
mbed_official 3:7a284390b0ce 27 *
mbed_official 3:7a284390b0ce 28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
mbed_official 3:7a284390b0ce 29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
mbed_official 3:7a284390b0ce 30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
mbed_official 3:7a284390b0ce 31 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
mbed_official 3:7a284390b0ce 32 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
mbed_official 3:7a284390b0ce 33 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
mbed_official 3:7a284390b0ce 34 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
mbed_official 3:7a284390b0ce 35 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
mbed_official 3:7a284390b0ce 36 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
mbed_official 3:7a284390b0ce 37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
mbed_official 3:7a284390b0ce 38 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
mbed_official 3:7a284390b0ce 39 * POSSIBILITY OF SUCH DAMAGE.
emilmont 1:fdd22bb7aa52 40 * -------------------------------------------------------------------- */
emilmont 1:fdd22bb7aa52 41
emilmont 1:fdd22bb7aa52 42 #include "arm_math.h"
emilmont 1:fdd22bb7aa52 43
mbed_official 3:7a284390b0ce 44 void arm_radix2_butterfly_f32(
mbed_official 3:7a284390b0ce 45 float32_t * pSrc,
mbed_official 3:7a284390b0ce 46 uint32_t fftLen,
mbed_official 3:7a284390b0ce 47 float32_t * pCoef,
mbed_official 3:7a284390b0ce 48 uint16_t twidCoefModifier);
mbed_official 3:7a284390b0ce 49
mbed_official 3:7a284390b0ce 50 void arm_radix2_butterfly_inverse_f32(
mbed_official 3:7a284390b0ce 51 float32_t * pSrc,
mbed_official 3:7a284390b0ce 52 uint32_t fftLen,
mbed_official 3:7a284390b0ce 53 float32_t * pCoef,
mbed_official 3:7a284390b0ce 54 uint16_t twidCoefModifier,
mbed_official 3:7a284390b0ce 55 float32_t onebyfftLen);
mbed_official 3:7a284390b0ce 56
mbed_official 3:7a284390b0ce 57 extern void arm_bitreversal_f32(
mbed_official 3:7a284390b0ce 58 float32_t * pSrc,
mbed_official 3:7a284390b0ce 59 uint16_t fftSize,
mbed_official 3:7a284390b0ce 60 uint16_t bitRevFactor,
mbed_official 3:7a284390b0ce 61 uint16_t * pBitRevTab);
mbed_official 3:7a284390b0ce 62
emilmont 1:fdd22bb7aa52 63 /**
mbed_official 3:7a284390b0ce 64 * @ingroup groupTransforms
mbed_official 3:7a284390b0ce 65 */
mbed_official 3:7a284390b0ce 66
mbed_official 3:7a284390b0ce 67 /**
mbed_official 3:7a284390b0ce 68 * @addtogroup ComplexFFT
mbed_official 3:7a284390b0ce 69 * @{
mbed_official 3:7a284390b0ce 70 */
emilmont 1:fdd22bb7aa52 71
emilmont 1:fdd22bb7aa52 72 /**
mbed_official 3:7a284390b0ce 73 * @details
mbed_official 3:7a284390b0ce 74 * @brief Radix-2 CFFT/CIFFT.
mbed_official 3:7a284390b0ce 75 * @deprecated Do not use this function. It has been superceded by \ref arm_cfft_f32 and will be removed
mbed_official 3:7a284390b0ce 76 * in the future.
mbed_official 3:7a284390b0ce 77 * @param[in] *S points to an instance of the floating-point Radix-2 CFFT/CIFFT structure.
mbed_official 3:7a284390b0ce 78 * @param[in, out] *pSrc points to the complex data buffer of size <code>2*fftLen</code>. Processing occurs in-place.
mbed_official 3:7a284390b0ce 79 * @return none.
mbed_official 3:7a284390b0ce 80 */
emilmont 1:fdd22bb7aa52 81
emilmont 1:fdd22bb7aa52 82 void arm_cfft_radix2_f32(
mbed_official 3:7a284390b0ce 83 const arm_cfft_radix2_instance_f32 * S,
mbed_official 3:7a284390b0ce 84 float32_t * pSrc)
emilmont 1:fdd22bb7aa52 85 {
emilmont 1:fdd22bb7aa52 86
mbed_official 3:7a284390b0ce 87 if(S->ifftFlag == 1u)
mbed_official 3:7a284390b0ce 88 {
mbed_official 3:7a284390b0ce 89 /* Complex IFFT radix-2 */
mbed_official 3:7a284390b0ce 90 arm_radix2_butterfly_inverse_f32(pSrc, S->fftLen, S->pTwiddle,
mbed_official 3:7a284390b0ce 91 S->twidCoefModifier, S->onebyfftLen);
mbed_official 3:7a284390b0ce 92 }
mbed_official 3:7a284390b0ce 93 else
mbed_official 3:7a284390b0ce 94 {
mbed_official 3:7a284390b0ce 95 /* Complex FFT radix-2 */
mbed_official 3:7a284390b0ce 96 arm_radix2_butterfly_f32(pSrc, S->fftLen, S->pTwiddle,
mbed_official 3:7a284390b0ce 97 S->twidCoefModifier);
mbed_official 3:7a284390b0ce 98 }
emilmont 1:fdd22bb7aa52 99
mbed_official 3:7a284390b0ce 100 if(S->bitReverseFlag == 1u)
mbed_official 3:7a284390b0ce 101 {
mbed_official 3:7a284390b0ce 102 /* Bit Reversal */
mbed_official 3:7a284390b0ce 103 arm_bitreversal_f32(pSrc, S->fftLen, S->bitRevFactor, S->pBitRevTable);
mbed_official 3:7a284390b0ce 104 }
emilmont 1:fdd22bb7aa52 105
emilmont 1:fdd22bb7aa52 106 }
emilmont 1:fdd22bb7aa52 107
emilmont 1:fdd22bb7aa52 108
emilmont 1:fdd22bb7aa52 109 /**
mbed_official 3:7a284390b0ce 110 * @} end of ComplexFFT group
mbed_official 3:7a284390b0ce 111 */
emilmont 1:fdd22bb7aa52 112
emilmont 1:fdd22bb7aa52 113
emilmont 1:fdd22bb7aa52 114
emilmont 1:fdd22bb7aa52 115 /* ----------------------------------------------------------------------
emilmont 1:fdd22bb7aa52 116 ** Internal helper function used by the FFTs
emilmont 1:fdd22bb7aa52 117 ** ------------------------------------------------------------------- */
emilmont 1:fdd22bb7aa52 118
emilmont 1:fdd22bb7aa52 119 /*
mbed_official 3:7a284390b0ce 120 * @brief Core function for the floating-point CFFT butterfly process.
mbed_official 3:7a284390b0ce 121 * @param[in, out] *pSrc points to the in-place buffer of floating-point data type.
mbed_official 3:7a284390b0ce 122 * @param[in] fftLen length of the FFT.
mbed_official 3:7a284390b0ce 123 * @param[in] *pCoef points to the twiddle coefficient buffer.
mbed_official 3:7a284390b0ce 124 * @param[in] twidCoefModifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table.
mbed_official 3:7a284390b0ce 125 * @return none.
mbed_official 3:7a284390b0ce 126 */
emilmont 1:fdd22bb7aa52 127
emilmont 1:fdd22bb7aa52 128 void arm_radix2_butterfly_f32(
mbed_official 3:7a284390b0ce 129 float32_t * pSrc,
mbed_official 3:7a284390b0ce 130 uint32_t fftLen,
mbed_official 3:7a284390b0ce 131 float32_t * pCoef,
mbed_official 3:7a284390b0ce 132 uint16_t twidCoefModifier)
emilmont 1:fdd22bb7aa52 133 {
emilmont 1:fdd22bb7aa52 134
mbed_official 3:7a284390b0ce 135 uint32_t i, j, k, l;
mbed_official 3:7a284390b0ce 136 uint32_t n1, n2, ia;
mbed_official 3:7a284390b0ce 137 float32_t xt, yt, cosVal, sinVal;
mbed_official 3:7a284390b0ce 138 float32_t p0, p1, p2, p3;
mbed_official 3:7a284390b0ce 139 float32_t a0, a1;
emilmont 1:fdd22bb7aa52 140
mbed_official 3:7a284390b0ce 141 #ifndef ARM_MATH_CM0_FAMILY
emilmont 1:fdd22bb7aa52 142
mbed_official 3:7a284390b0ce 143 /* Initializations for the first stage */
mbed_official 3:7a284390b0ce 144 n2 = fftLen >> 1;
mbed_official 3:7a284390b0ce 145 ia = 0;
mbed_official 3:7a284390b0ce 146 i = 0;
emilmont 1:fdd22bb7aa52 147
mbed_official 3:7a284390b0ce 148 // loop for groups
mbed_official 3:7a284390b0ce 149 for (k = n2; k > 0; k--)
mbed_official 3:7a284390b0ce 150 {
emilmont 1:fdd22bb7aa52 151 cosVal = pCoef[ia * 2];
emilmont 1:fdd22bb7aa52 152 sinVal = pCoef[(ia * 2) + 1];
mbed_official 3:7a284390b0ce 153
mbed_official 3:7a284390b0ce 154 /* Twiddle coefficients index modifier */
mbed_official 3:7a284390b0ce 155 ia += twidCoefModifier;
emilmont 1:fdd22bb7aa52 156
mbed_official 3:7a284390b0ce 157 /* index calculation for the input as, */
mbed_official 3:7a284390b0ce 158 /* pSrc[i + 0], pSrc[i + fftLen/1] */
mbed_official 3:7a284390b0ce 159 l = i + n2;
mbed_official 3:7a284390b0ce 160
mbed_official 3:7a284390b0ce 161 /* Butterfly implementation */
mbed_official 3:7a284390b0ce 162 a0 = pSrc[2 * i] + pSrc[2 * l];
mbed_official 3:7a284390b0ce 163 xt = pSrc[2 * i] - pSrc[2 * l];
emilmont 1:fdd22bb7aa52 164
mbed_official 3:7a284390b0ce 165 yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];
mbed_official 3:7a284390b0ce 166 a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1];
mbed_official 3:7a284390b0ce 167
mbed_official 3:7a284390b0ce 168 p0 = xt * cosVal;
mbed_official 3:7a284390b0ce 169 p1 = yt * sinVal;
mbed_official 3:7a284390b0ce 170 p2 = yt * cosVal;
mbed_official 3:7a284390b0ce 171 p3 = xt * sinVal;
mbed_official 3:7a284390b0ce 172
mbed_official 3:7a284390b0ce 173 pSrc[2 * i] = a0;
mbed_official 3:7a284390b0ce 174 pSrc[2 * i + 1] = a1;
mbed_official 3:7a284390b0ce 175
mbed_official 3:7a284390b0ce 176 pSrc[2 * l] = p0 + p1;
mbed_official 3:7a284390b0ce 177 pSrc[2 * l + 1] = p2 - p3;
mbed_official 3:7a284390b0ce 178
mbed_official 3:7a284390b0ce 179 i++;
mbed_official 3:7a284390b0ce 180 } // groups loop end
emilmont 1:fdd22bb7aa52 181
mbed_official 3:7a284390b0ce 182 twidCoefModifier <<= 1u;
emilmont 1:fdd22bb7aa52 183
mbed_official 3:7a284390b0ce 184 // loop for stage
mbed_official 3:7a284390b0ce 185 for (k = n2; k > 2; k = k >> 1)
mbed_official 3:7a284390b0ce 186 {
mbed_official 3:7a284390b0ce 187 n1 = n2;
mbed_official 3:7a284390b0ce 188 n2 = n2 >> 1;
mbed_official 3:7a284390b0ce 189 ia = 0;
emilmont 1:fdd22bb7aa52 190
mbed_official 3:7a284390b0ce 191 // loop for groups
mbed_official 3:7a284390b0ce 192 j = 0;
mbed_official 3:7a284390b0ce 193 do
mbed_official 3:7a284390b0ce 194 {
mbed_official 3:7a284390b0ce 195 cosVal = pCoef[ia * 2];
mbed_official 3:7a284390b0ce 196 sinVal = pCoef[(ia * 2) + 1];
mbed_official 3:7a284390b0ce 197 ia += twidCoefModifier;
emilmont 1:fdd22bb7aa52 198
mbed_official 3:7a284390b0ce 199 // loop for butterfly
mbed_official 3:7a284390b0ce 200 i = j;
mbed_official 3:7a284390b0ce 201 do
mbed_official 3:7a284390b0ce 202 {
mbed_official 3:7a284390b0ce 203 l = i + n2;
mbed_official 3:7a284390b0ce 204 a0 = pSrc[2 * i] + pSrc[2 * l];
mbed_official 3:7a284390b0ce 205 xt = pSrc[2 * i] - pSrc[2 * l];
emilmont 1:fdd22bb7aa52 206
mbed_official 3:7a284390b0ce 207 yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];
mbed_official 3:7a284390b0ce 208 a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1];
mbed_official 3:7a284390b0ce 209
mbed_official 3:7a284390b0ce 210 p0 = xt * cosVal;
mbed_official 3:7a284390b0ce 211 p1 = yt * sinVal;
mbed_official 3:7a284390b0ce 212 p2 = yt * cosVal;
mbed_official 3:7a284390b0ce 213 p3 = xt * sinVal;
mbed_official 3:7a284390b0ce 214
mbed_official 3:7a284390b0ce 215 pSrc[2 * i] = a0;
mbed_official 3:7a284390b0ce 216 pSrc[2 * i + 1] = a1;
mbed_official 3:7a284390b0ce 217
mbed_official 3:7a284390b0ce 218 pSrc[2 * l] = p0 + p1;
mbed_official 3:7a284390b0ce 219 pSrc[2 * l + 1] = p2 - p3;
mbed_official 3:7a284390b0ce 220
mbed_official 3:7a284390b0ce 221 i += n1;
mbed_official 3:7a284390b0ce 222 } while( i < fftLen ); // butterfly loop end
mbed_official 3:7a284390b0ce 223 j++;
mbed_official 3:7a284390b0ce 224 } while( j < n2); // groups loop end
mbed_official 3:7a284390b0ce 225 twidCoefModifier <<= 1u;
mbed_official 3:7a284390b0ce 226 } // stages loop end
emilmont 1:fdd22bb7aa52 227
mbed_official 3:7a284390b0ce 228 // loop for butterfly
mbed_official 3:7a284390b0ce 229 for (i = 0; i < fftLen; i += 2)
mbed_official 3:7a284390b0ce 230 {
mbed_official 3:7a284390b0ce 231 a0 = pSrc[2 * i] + pSrc[2 * i + 2];
mbed_official 3:7a284390b0ce 232 xt = pSrc[2 * i] - pSrc[2 * i + 2];
emilmont 1:fdd22bb7aa52 233
mbed_official 3:7a284390b0ce 234 yt = pSrc[2 * i + 1] - pSrc[2 * i + 3];
mbed_official 3:7a284390b0ce 235 a1 = pSrc[2 * i + 3] + pSrc[2 * i + 1];
mbed_official 3:7a284390b0ce 236
mbed_official 3:7a284390b0ce 237 pSrc[2 * i] = a0;
mbed_official 3:7a284390b0ce 238 pSrc[2 * i + 1] = a1;
mbed_official 3:7a284390b0ce 239 pSrc[2 * i + 2] = xt;
mbed_official 3:7a284390b0ce 240 pSrc[2 * i + 3] = yt;
mbed_official 3:7a284390b0ce 241 } // groups loop end
emilmont 1:fdd22bb7aa52 242
emilmont 1:fdd22bb7aa52 243 #else
mbed_official 3:7a284390b0ce 244
mbed_official 3:7a284390b0ce 245 n2 = fftLen;
emilmont 1:fdd22bb7aa52 246
mbed_official 3:7a284390b0ce 247 // loop for stage
mbed_official 3:7a284390b0ce 248 for (k = fftLen; k > 1; k = k >> 1)
mbed_official 3:7a284390b0ce 249 {
mbed_official 3:7a284390b0ce 250 n1 = n2;
mbed_official 3:7a284390b0ce 251 n2 = n2 >> 1;
mbed_official 3:7a284390b0ce 252 ia = 0;
emilmont 1:fdd22bb7aa52 253
mbed_official 3:7a284390b0ce 254 // loop for groups
mbed_official 3:7a284390b0ce 255 j = 0;
mbed_official 3:7a284390b0ce 256 do
mbed_official 3:7a284390b0ce 257 {
mbed_official 3:7a284390b0ce 258 cosVal = pCoef[ia * 2];
mbed_official 3:7a284390b0ce 259 sinVal = pCoef[(ia * 2) + 1];
mbed_official 3:7a284390b0ce 260 ia += twidCoefModifier;
emilmont 1:fdd22bb7aa52 261
mbed_official 3:7a284390b0ce 262 // loop for butterfly
mbed_official 3:7a284390b0ce 263 i = j;
mbed_official 3:7a284390b0ce 264 do
mbed_official 3:7a284390b0ce 265 {
mbed_official 3:7a284390b0ce 266 l = i + n2;
mbed_official 3:7a284390b0ce 267 a0 = pSrc[2 * i] + pSrc[2 * l];
mbed_official 3:7a284390b0ce 268 xt = pSrc[2 * i] - pSrc[2 * l];
emilmont 1:fdd22bb7aa52 269
mbed_official 3:7a284390b0ce 270 yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];
mbed_official 3:7a284390b0ce 271 a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1];
mbed_official 3:7a284390b0ce 272
mbed_official 3:7a284390b0ce 273 p0 = xt * cosVal;
mbed_official 3:7a284390b0ce 274 p1 = yt * sinVal;
mbed_official 3:7a284390b0ce 275 p2 = yt * cosVal;
mbed_official 3:7a284390b0ce 276 p3 = xt * sinVal;
mbed_official 3:7a284390b0ce 277
mbed_official 3:7a284390b0ce 278 pSrc[2 * i] = a0;
mbed_official 3:7a284390b0ce 279 pSrc[2 * i + 1] = a1;
mbed_official 3:7a284390b0ce 280
mbed_official 3:7a284390b0ce 281 pSrc[2 * l] = p0 + p1;
mbed_official 3:7a284390b0ce 282 pSrc[2 * l + 1] = p2 - p3;
mbed_official 3:7a284390b0ce 283
mbed_official 3:7a284390b0ce 284 i += n1;
mbed_official 3:7a284390b0ce 285 } while(i < fftLen);
mbed_official 3:7a284390b0ce 286 j++;
mbed_official 3:7a284390b0ce 287 } while(j < n2);
mbed_official 3:7a284390b0ce 288 twidCoefModifier <<= 1u;
mbed_official 3:7a284390b0ce 289 }
emilmont 1:fdd22bb7aa52 290
mbed_official 3:7a284390b0ce 291 #endif // #ifndef ARM_MATH_CM0_FAMILY
emilmont 1:fdd22bb7aa52 292
emilmont 1:fdd22bb7aa52 293 }
emilmont 1:fdd22bb7aa52 294
emilmont 1:fdd22bb7aa52 295
emilmont 1:fdd22bb7aa52 296 void arm_radix2_butterfly_inverse_f32(
mbed_official 3:7a284390b0ce 297 float32_t * pSrc,
mbed_official 3:7a284390b0ce 298 uint32_t fftLen,
mbed_official 3:7a284390b0ce 299 float32_t * pCoef,
mbed_official 3:7a284390b0ce 300 uint16_t twidCoefModifier,
mbed_official 3:7a284390b0ce 301 float32_t onebyfftLen)
emilmont 1:fdd22bb7aa52 302 {
emilmont 1:fdd22bb7aa52 303
mbed_official 3:7a284390b0ce 304 uint32_t i, j, k, l;
mbed_official 3:7a284390b0ce 305 uint32_t n1, n2, ia;
mbed_official 3:7a284390b0ce 306 float32_t xt, yt, cosVal, sinVal;
mbed_official 3:7a284390b0ce 307 float32_t p0, p1, p2, p3;
mbed_official 3:7a284390b0ce 308 float32_t a0, a1;
emilmont 1:fdd22bb7aa52 309
mbed_official 3:7a284390b0ce 310 #ifndef ARM_MATH_CM0_FAMILY
emilmont 1:fdd22bb7aa52 311
mbed_official 3:7a284390b0ce 312 n2 = fftLen >> 1;
mbed_official 3:7a284390b0ce 313 ia = 0;
emilmont 1:fdd22bb7aa52 314
mbed_official 3:7a284390b0ce 315 // loop for groups
mbed_official 3:7a284390b0ce 316 for (i = 0; i < n2; i++)
mbed_official 3:7a284390b0ce 317 {
emilmont 1:fdd22bb7aa52 318 cosVal = pCoef[ia * 2];
emilmont 1:fdd22bb7aa52 319 sinVal = pCoef[(ia * 2) + 1];
mbed_official 3:7a284390b0ce 320 ia += twidCoefModifier;
emilmont 1:fdd22bb7aa52 321
mbed_official 3:7a284390b0ce 322 l = i + n2;
mbed_official 3:7a284390b0ce 323 a0 = pSrc[2 * i] + pSrc[2 * l];
mbed_official 3:7a284390b0ce 324 xt = pSrc[2 * i] - pSrc[2 * l];
emilmont 1:fdd22bb7aa52 325
mbed_official 3:7a284390b0ce 326 yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];
mbed_official 3:7a284390b0ce 327 a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1];
mbed_official 3:7a284390b0ce 328
mbed_official 3:7a284390b0ce 329 p0 = xt * cosVal;
mbed_official 3:7a284390b0ce 330 p1 = yt * sinVal;
mbed_official 3:7a284390b0ce 331 p2 = yt * cosVal;
mbed_official 3:7a284390b0ce 332 p3 = xt * sinVal;
mbed_official 3:7a284390b0ce 333
mbed_official 3:7a284390b0ce 334 pSrc[2 * i] = a0;
mbed_official 3:7a284390b0ce 335 pSrc[2 * i + 1] = a1;
mbed_official 3:7a284390b0ce 336
mbed_official 3:7a284390b0ce 337 pSrc[2 * l] = p0 - p1;
mbed_official 3:7a284390b0ce 338 pSrc[2 * l + 1] = p2 + p3;
mbed_official 3:7a284390b0ce 339 } // groups loop end
emilmont 1:fdd22bb7aa52 340
mbed_official 3:7a284390b0ce 341 twidCoefModifier <<= 1u;
emilmont 1:fdd22bb7aa52 342
mbed_official 3:7a284390b0ce 343 // loop for stage
mbed_official 3:7a284390b0ce 344 for (k = fftLen / 2; k > 2; k = k >> 1)
mbed_official 3:7a284390b0ce 345 {
mbed_official 3:7a284390b0ce 346 n1 = n2;
mbed_official 3:7a284390b0ce 347 n2 = n2 >> 1;
mbed_official 3:7a284390b0ce 348 ia = 0;
emilmont 1:fdd22bb7aa52 349
mbed_official 3:7a284390b0ce 350 // loop for groups
mbed_official 3:7a284390b0ce 351 j = 0;
mbed_official 3:7a284390b0ce 352 do
mbed_official 3:7a284390b0ce 353 {
mbed_official 3:7a284390b0ce 354 cosVal = pCoef[ia * 2];
mbed_official 3:7a284390b0ce 355 sinVal = pCoef[(ia * 2) + 1];
mbed_official 3:7a284390b0ce 356 ia += twidCoefModifier;
emilmont 1:fdd22bb7aa52 357
mbed_official 3:7a284390b0ce 358 // loop for butterfly
mbed_official 3:7a284390b0ce 359 i = j;
mbed_official 3:7a284390b0ce 360 do
mbed_official 3:7a284390b0ce 361 {
mbed_official 3:7a284390b0ce 362 l = i + n2;
mbed_official 3:7a284390b0ce 363 a0 = pSrc[2 * i] + pSrc[2 * l];
mbed_official 3:7a284390b0ce 364 xt = pSrc[2 * i] - pSrc[2 * l];
emilmont 1:fdd22bb7aa52 365
mbed_official 3:7a284390b0ce 366 yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];
mbed_official 3:7a284390b0ce 367 a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1];
mbed_official 3:7a284390b0ce 368
mbed_official 3:7a284390b0ce 369 p0 = xt * cosVal;
mbed_official 3:7a284390b0ce 370 p1 = yt * sinVal;
mbed_official 3:7a284390b0ce 371 p2 = yt * cosVal;
mbed_official 3:7a284390b0ce 372 p3 = xt * sinVal;
mbed_official 3:7a284390b0ce 373
mbed_official 3:7a284390b0ce 374 pSrc[2 * i] = a0;
mbed_official 3:7a284390b0ce 375 pSrc[2 * i + 1] = a1;
mbed_official 3:7a284390b0ce 376
mbed_official 3:7a284390b0ce 377 pSrc[2 * l] = p0 - p1;
mbed_official 3:7a284390b0ce 378 pSrc[2 * l + 1] = p2 + p3;
emilmont 1:fdd22bb7aa52 379
mbed_official 3:7a284390b0ce 380 i += n1;
mbed_official 3:7a284390b0ce 381 } while( i < fftLen ); // butterfly loop end
mbed_official 3:7a284390b0ce 382 j++;
mbed_official 3:7a284390b0ce 383 } while(j < n2); // groups loop end
mbed_official 3:7a284390b0ce 384
mbed_official 3:7a284390b0ce 385 twidCoefModifier <<= 1u;
mbed_official 3:7a284390b0ce 386 } // stages loop end
emilmont 1:fdd22bb7aa52 387
mbed_official 3:7a284390b0ce 388 // loop for butterfly
mbed_official 3:7a284390b0ce 389 for (i = 0; i < fftLen; i += 2)
mbed_official 3:7a284390b0ce 390 {
mbed_official 3:7a284390b0ce 391 a0 = pSrc[2 * i] + pSrc[2 * i + 2];
mbed_official 3:7a284390b0ce 392 xt = pSrc[2 * i] - pSrc[2 * i + 2];
mbed_official 3:7a284390b0ce 393
mbed_official 3:7a284390b0ce 394 a1 = pSrc[2 * i + 3] + pSrc[2 * i + 1];
mbed_official 3:7a284390b0ce 395 yt = pSrc[2 * i + 1] - pSrc[2 * i + 3];
mbed_official 3:7a284390b0ce 396
mbed_official 3:7a284390b0ce 397 p0 = a0 * onebyfftLen;
mbed_official 3:7a284390b0ce 398 p2 = xt * onebyfftLen;
mbed_official 3:7a284390b0ce 399 p1 = a1 * onebyfftLen;
mbed_official 3:7a284390b0ce 400 p3 = yt * onebyfftLen;
mbed_official 3:7a284390b0ce 401
mbed_official 3:7a284390b0ce 402 pSrc[2 * i] = p0;
mbed_official 3:7a284390b0ce 403 pSrc[2 * i + 1] = p1;
mbed_official 3:7a284390b0ce 404 pSrc[2 * i + 2] = p2;
mbed_official 3:7a284390b0ce 405 pSrc[2 * i + 3] = p3;
mbed_official 3:7a284390b0ce 406 } // butterfly loop end
emilmont 1:fdd22bb7aa52 407
emilmont 1:fdd22bb7aa52 408 #else
emilmont 1:fdd22bb7aa52 409
mbed_official 3:7a284390b0ce 410 n2 = fftLen;
emilmont 1:fdd22bb7aa52 411
mbed_official 3:7a284390b0ce 412 // loop for stage
mbed_official 3:7a284390b0ce 413 for (k = fftLen; k > 2; k = k >> 1)
mbed_official 3:7a284390b0ce 414 {
mbed_official 3:7a284390b0ce 415 n1 = n2;
mbed_official 3:7a284390b0ce 416 n2 = n2 >> 1;
mbed_official 3:7a284390b0ce 417 ia = 0;
emilmont 1:fdd22bb7aa52 418
mbed_official 3:7a284390b0ce 419 // loop for groups
mbed_official 3:7a284390b0ce 420 j = 0;
mbed_official 3:7a284390b0ce 421 do
emilmont 1:fdd22bb7aa52 422 {
mbed_official 3:7a284390b0ce 423 cosVal = pCoef[ia * 2];
mbed_official 3:7a284390b0ce 424 sinVal = pCoef[(ia * 2) + 1];
mbed_official 3:7a284390b0ce 425 ia = ia + twidCoefModifier;
emilmont 1:fdd22bb7aa52 426
mbed_official 3:7a284390b0ce 427 // loop for butterfly
mbed_official 3:7a284390b0ce 428 i = j;
mbed_official 3:7a284390b0ce 429 do
mbed_official 3:7a284390b0ce 430 {
mbed_official 3:7a284390b0ce 431 l = i + n2;
mbed_official 3:7a284390b0ce 432 a0 = pSrc[2 * i] + pSrc[2 * l];
mbed_official 3:7a284390b0ce 433 xt = pSrc[2 * i] - pSrc[2 * l];
emilmont 1:fdd22bb7aa52 434
mbed_official 3:7a284390b0ce 435 yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];
mbed_official 3:7a284390b0ce 436 a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1];
mbed_official 3:7a284390b0ce 437
mbed_official 3:7a284390b0ce 438 p0 = xt * cosVal;
mbed_official 3:7a284390b0ce 439 p1 = yt * sinVal;
mbed_official 3:7a284390b0ce 440 p2 = yt * cosVal;
mbed_official 3:7a284390b0ce 441 p3 = xt * sinVal;
mbed_official 3:7a284390b0ce 442
mbed_official 3:7a284390b0ce 443 pSrc[2 * i] = a0;
mbed_official 3:7a284390b0ce 444 pSrc[2 * i + 1] = a1;
mbed_official 3:7a284390b0ce 445
mbed_official 3:7a284390b0ce 446 pSrc[2 * l] = p0 - p1;
mbed_official 3:7a284390b0ce 447 pSrc[2 * l + 1] = p2 + p3;
mbed_official 3:7a284390b0ce 448
mbed_official 3:7a284390b0ce 449 i += n1;
mbed_official 3:7a284390b0ce 450 } while( i < fftLen ); // butterfly loop end
mbed_official 3:7a284390b0ce 451 j++;
mbed_official 3:7a284390b0ce 452 } while( j < n2 ); // groups loop end
emilmont 1:fdd22bb7aa52 453
mbed_official 3:7a284390b0ce 454 twidCoefModifier = twidCoefModifier << 1u;
mbed_official 3:7a284390b0ce 455 } // stages loop end
emilmont 1:fdd22bb7aa52 456
mbed_official 3:7a284390b0ce 457 n1 = n2;
mbed_official 3:7a284390b0ce 458 n2 = n2 >> 1;
emilmont 1:fdd22bb7aa52 459
mbed_official 3:7a284390b0ce 460 // loop for butterfly
mbed_official 3:7a284390b0ce 461 for (i = 0; i < fftLen; i += n1)
mbed_official 3:7a284390b0ce 462 {
mbed_official 3:7a284390b0ce 463 l = i + n2;
mbed_official 3:7a284390b0ce 464
mbed_official 3:7a284390b0ce 465 a0 = pSrc[2 * i] + pSrc[2 * l];
mbed_official 3:7a284390b0ce 466 xt = pSrc[2 * i] - pSrc[2 * l];
mbed_official 3:7a284390b0ce 467
mbed_official 3:7a284390b0ce 468 a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1];
mbed_official 3:7a284390b0ce 469 yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];
mbed_official 3:7a284390b0ce 470
mbed_official 3:7a284390b0ce 471 p0 = a0 * onebyfftLen;
mbed_official 3:7a284390b0ce 472 p2 = xt * onebyfftLen;
mbed_official 3:7a284390b0ce 473 p1 = a1 * onebyfftLen;
mbed_official 3:7a284390b0ce 474 p3 = yt * onebyfftLen;
mbed_official 3:7a284390b0ce 475
mbed_official 3:7a284390b0ce 476 pSrc[2 * i] = p0;
mbed_official 3:7a284390b0ce 477 pSrc[2u * l] = p2;
mbed_official 3:7a284390b0ce 478
mbed_official 3:7a284390b0ce 479 pSrc[2 * i + 1] = p1;
mbed_official 3:7a284390b0ce 480 pSrc[2u * l + 1u] = p3;
mbed_official 3:7a284390b0ce 481 } // butterfly loop end
emilmont 1:fdd22bb7aa52 482
mbed_official 3:7a284390b0ce 483 #endif // #ifndef ARM_MATH_CM0_FAMILY
emilmont 1:fdd22bb7aa52 484
emilmont 1:fdd22bb7aa52 485 }