arm_cfft_f64.c
1 /* ---------------------------------------------------------------------- 2 * Project: CMSIS DSP Library 3 * Title: arm_cfft_f64.c 4 * Description: Combined Radix Decimation in Frequency CFFT Double Precision Floating point processing function 5 * 6 * $Date: 23 April 2021 7 * $Revision: V1.9.0 8 * 9 * Target Processor: Cortex-M and Cortex-A cores 10 * -------------------------------------------------------------------- */ 11 /* 12 * Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved. 13 * 14 * SPDX-License-Identifier: Apache-2.0 15 * 16 * Licensed under the Apache License, Version 2.0 (the License); you may 17 * not use this file except in compliance with the License. 18 * You may obtain a copy of the License at 19 * 20 * www.apache.org/licenses/LICENSE-2.0 21 * 22 * Unless required by applicable law or agreed to in writing, software 23 * distributed under the License is distributed on an AS IS BASIS, WITHOUT 24 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 25 * See the License for the specific language governing permissions and 26 * limitations under the License. 27 */ 28 29 #include "dsp/transform_functions.h" 30 #include "arm_common_tables.h" 31 32 33 extern void arm_radix4_butterfly_f64( 34 float64_t * pSrc, 35 uint16_t fftLen, 36 const float64_t * pCoef, 37 uint16_t twidCoefModifier); 38 39 extern void arm_bitreversal_64( 40 uint64_t * pSrc, 41 const uint16_t bitRevLen, 42 const uint16_t * pBitRevTable); 43 44 /** 45 * @} end of ComplexFFT group 46 */ 47 48 /* ---------------------------------------------------------------------- 49 * Internal helper function used by the FFTs 50 * ---------------------------------------------------------------------- */ 51 52 /* 53 * @brief Core function for the Double Precision floating-point CFFT butterfly process. 54 * @param[in, out] *pSrc points to the in-place buffer of F64 data type. 55 * @param[in] fftLen length of the FFT. 56 * @param[in] *pCoef points to the twiddle coefficient buffer. 57 * @param[in] twidCoefModifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table. 58 * @return none. 59 */ 60 61 void arm_radix4_butterfly_f64( 62 float64_t * pSrc, 63 uint16_t fftLen, 64 const float64_t * pCoef, 65 uint16_t twidCoefModifier) 66 { 67 68 float64_t co1, co2, co3, si1, si2, si3; 69 uint32_t ia1, ia2, ia3; 70 uint32_t i0, i1, i2, i3; 71 uint32_t n1, n2, j, k; 72 73 float64_t t1, t2, r1, r2, s1, s2; 74 75 76 /* Initializations for the fft calculation */ 77 n2 = fftLen; 78 n1 = n2; 79 for (k = fftLen; k > 1U; k >>= 2U) 80 { 81 /* Initializations for the fft calculation */ 82 n1 = n2; 83 n2 >>= 2U; 84 ia1 = 0U; 85 86 /* FFT Calculation */ 87 j = 0; 88 do 89 { 90 /* index calculation for the coefficients */ 91 ia2 = ia1 + ia1; 92 ia3 = ia2 + ia1; 93 co1 = pCoef[ia1 * 2U]; 94 si1 = pCoef[(ia1 * 2U) + 1U]; 95 co2 = pCoef[ia2 * 2U]; 96 si2 = pCoef[(ia2 * 2U) + 1U]; 97 co3 = pCoef[ia3 * 2U]; 98 si3 = pCoef[(ia3 * 2U) + 1U]; 99 100 /* Twiddle coefficients index modifier */ 101 ia1 = ia1 + twidCoefModifier; 102 103 i0 = j; 104 do 105 { 106 /* index calculation for the input as, */ 107 /* pSrc[i0 + 0], pSrc[i0 + fftLen/4], pSrc[i0 + fftLen/2], pSrc[i0 + 3fftLen/4] */ 108 i1 = i0 + n2; 109 i2 = i1 + n2; 110 i3 = i2 + n2; 111 112 /* xa + xc */ 113 r1 = pSrc[(2U * i0)] + pSrc[(2U * i2)]; 114 115 /* xa - xc */ 116 r2 = pSrc[(2U * i0)] - pSrc[(2U * i2)]; 117 118 /* ya + yc */ 119 s1 = pSrc[(2U * i0) + 1U] + pSrc[(2U * i2) + 1U]; 120 121 /* ya - yc */ 122 s2 = pSrc[(2U * i0) + 1U] - pSrc[(2U * i2) + 1U]; 123 124 /* xb + xd */ 125 t1 = pSrc[2U * i1] + pSrc[2U * i3]; 126 127 /* xa' = xa + xb + xc + xd */ 128 pSrc[2U * i0] = r1 + t1; 129 130 /* xa + xc -(xb + xd) */ 131 r1 = r1 - t1; 132 133 /* yb + yd */ 134 t2 = pSrc[(2U * i1) + 1U] + pSrc[(2U * i3) + 1U]; 135 136 /* ya' = ya + yb + yc + yd */ 137 pSrc[(2U * i0) + 1U] = s1 + t2; 138 139 /* (ya + yc) - (yb + yd) */ 140 s1 = s1 - t2; 141 142 /* (yb - yd) */ 143 t1 = pSrc[(2U * i1) + 1U] - pSrc[(2U * i3) + 1U]; 144 145 /* (xb - xd) */ 146 t2 = pSrc[2U * i1] - pSrc[2U * i3]; 147 148 /* xc' = (xa-xb+xc-xd)co2 + (ya-yb+yc-yd)(si2) */ 149 pSrc[2U * i1] = (r1 * co2) + (s1 * si2); 150 151 /* yc' = (ya-yb+yc-yd)co2 - (xa-xb+xc-xd)(si2) */ 152 pSrc[(2U * i1) + 1U] = (s1 * co2) - (r1 * si2); 153 154 /* (xa - xc) + (yb - yd) */ 155 r1 = r2 + t1; 156 157 /* (xa - xc) - (yb - yd) */ 158 r2 = r2 - t1; 159 160 /* (ya - yc) - (xb - xd) */ 161 s1 = s2 - t2; 162 163 /* (ya - yc) + (xb - xd) */ 164 s2 = s2 + t2; 165 166 /* xb' = (xa+yb-xc-yd)co1 + (ya-xb-yc+xd)(si1) */ 167 pSrc[2U * i2] = (r1 * co1) + (s1 * si1); 168 169 /* yb' = (ya-xb-yc+xd)co1 - (xa+yb-xc-yd)(si1) */ 170 pSrc[(2U * i2) + 1U] = (s1 * co1) - (r1 * si1); 171 172 /* xd' = (xa-yb-xc+yd)co3 + (ya+xb-yc-xd)(si3) */ 173 pSrc[2U * i3] = (r2 * co3) + (s2 * si3); 174 175 /* yd' = (ya+xb-yc-xd)co3 - (xa-yb-xc+yd)(si3) */ 176 pSrc[(2U * i3) + 1U] = (s2 * co3) - (r2 * si3); 177 178 i0 += n1; 179 } while ( i0 < fftLen); 180 j++; 181 } while (j <= (n2 - 1U)); 182 twidCoefModifier <<= 2U; 183 } 184 } 185 186 /* 187 * @brief Core function for the Double Precision floating-point CFFT butterfly process. 188 * @param[in, out] *pSrc points to the in-place buffer of F64 data type. 189 * @param[in] fftLen length of the FFT. 190 * @param[in] *pCoef points to the twiddle coefficient buffer. 191 * @param[in] twidCoefModifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table. 192 * @return none. 193 */ 194 195 void arm_cfft_radix4by2_f64( 196 float64_t * pSrc, 197 uint32_t fftLen, 198 const float64_t * pCoef) 199 { 200 uint32_t i, l; 201 uint32_t n2, ia; 202 float64_t xt, yt, cosVal, sinVal; 203 float64_t p0, p1,p2,p3,a0,a1; 204 205 n2 = fftLen >> 1; 206 ia = 0; 207 for (i = 0; i < n2; i++) 208 { 209 cosVal = pCoef[2*ia]; 210 sinVal = pCoef[2*ia + 1]; 211 ia++; 212 213 l = i + n2; 214 215 /* Butterfly implementation */ 216 a0 = pSrc[2 * i] + pSrc[2 * l]; 217 xt = pSrc[2 * i] - pSrc[2 * l]; 218 219 yt = pSrc[2 * i + 1] - pSrc[2 * l + 1]; 220 a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1]; 221 222 p0 = xt * cosVal; 223 p1 = yt * sinVal; 224 p2 = yt * cosVal; 225 p3 = xt * sinVal; 226 227 pSrc[2 * i] = a0; 228 pSrc[2 * i + 1] = a1; 229 230 pSrc[2 * l] = p0 + p1; 231 pSrc[2 * l + 1] = p2 - p3; 232 233 } 234 235 // first col 236 arm_radix4_butterfly_f64( pSrc, n2, (float64_t*)pCoef, 2U); 237 // second col 238 arm_radix4_butterfly_f64( pSrc + fftLen, n2, (float64_t*)pCoef, 2U); 239 240 } 241 242 /** 243 @addtogroup ComplexFFT 244 @{ 245 */ 246 247 /** 248 @brief Processing function for the Double Precision floating-point complex FFT. 249 @param[in] S points to an instance of the Double Precision floating-point CFFT structure 250 @param[in,out] p1 points to the complex data buffer of size <code>2*fftLen</code>. Processing occurs in-place 251 @param[in] ifftFlag flag that selects transform direction 252 - value = 0: forward transform 253 - value = 1: inverse transform 254 @param[in] bitReverseFlag flag that enables / disables bit reversal of output 255 - value = 0: disables bit reversal of output 256 - value = 1: enables bit reversal of output 257 @return none 258 */ 259 260 void arm_cfft_f64( 261 const arm_cfft_instance_f64 * S, 262 float64_t * p1, 263 uint8_t ifftFlag, 264 uint8_t bitReverseFlag) 265 { 266 uint32_t L = S->fftLen, l; 267 float64_t invL, * pSrc; 268 269 if (ifftFlag == 1U) 270 { 271 /* Conjugate input data */ 272 pSrc = p1 + 1; 273 for(l=0; l<L; l++) 274 { 275 *pSrc = -*pSrc; 276 pSrc += 2; 277 } 278 } 279 280 switch (L) 281 { 282 case 16: 283 case 64: 284 case 256: 285 case 1024: 286 case 4096: 287 arm_radix4_butterfly_f64 (p1, L, (float64_t*)S->pTwiddle, 1U); 288 break; 289 290 case 32: 291 case 128: 292 case 512: 293 case 2048: 294 arm_cfft_radix4by2_f64 ( p1, L, (float64_t*)S->pTwiddle); 295 break; 296 297 } 298 299 if ( bitReverseFlag ) 300 arm_bitreversal_64((uint64_t*)p1, S->bitRevLength,S->pBitRevTable); 301 302 if (ifftFlag == 1U) 303 { 304 invL = 1.0 / (float64_t)L; 305 /* Conjugate and scale output data */ 306 pSrc = p1; 307 for(l=0; l<L; l++) 308 { 309 *pSrc++ *= invL ; 310 *pSrc = -(*pSrc) * invL; 311 pSrc++; 312 } 313 } 314 } 315 316 /** 317 @} end of ComplexFFT group 318 */