| /* ---------------------------------------------------------------------- | |
| * Project: CMSIS DSP Library | |
| * Title: arm_cfft_f64.c | |
| * Description: Combined Radix Decimation in Frequency CFFT Double Precision Floating point processing function | |
| * | |
| * $Date: 23 April 2021 | |
| * $Revision: V1.9.0 | |
| * | |
| * Target Processor: Cortex-M and Cortex-A cores | |
| * -------------------------------------------------------------------- */ | |
| /* | |
| * Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved. | |
| * | |
| * SPDX-License-Identifier: Apache-2.0 | |
| * | |
| * Licensed under the Apache License, Version 2.0 (the License); you may | |
| * not use this file except in compliance with the License. | |
| * You may obtain a copy of the License at | |
| * | |
| * www.apache.org/licenses/LICENSE-2.0 | |
| * | |
| * Unless required by applicable law or agreed to in writing, software | |
| * distributed under the License is distributed on an AS IS BASIS, WITHOUT | |
| * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
| * See the License for the specific language governing permissions and | |
| * limitations under the License. | |
| */ | |
| extern void arm_radix4_butterfly_f64( | |
| float64_t * pSrc, | |
| uint16_t fftLen, | |
| const float64_t * pCoef, | |
| uint16_t twidCoefModifier); | |
| extern void arm_bitreversal_64( | |
| uint64_t * pSrc, | |
| const uint16_t bitRevLen, | |
| const uint16_t * pBitRevTable); | |
| /* ---------------------------------------------------------------------- | |
| * Internal helper function used by the FFTs | |
| * ---------------------------------------------------------------------- */ | |
| /* | |
| * @brief Core function for the Double Precision floating-point CFFT butterfly process. | |
| * @param[in, out] *pSrc points to the in-place buffer of F64 data type. | |
| * @param[in] fftLen length of the FFT. | |
| * @param[in] *pCoef points to the twiddle coefficient buffer. | |
| * @param[in] twidCoefModifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table. | |
| * @return none. | |
| */ | |
| void arm_radix4_butterfly_f64( | |
| float64_t * pSrc, | |
| uint16_t fftLen, | |
| const float64_t * pCoef, | |
| uint16_t twidCoefModifier) | |
| { | |
| float64_t co1, co2, co3, si1, si2, si3; | |
| uint32_t ia1, ia2, ia3; | |
| uint32_t i0, i1, i2, i3; | |
| uint32_t n1, n2, j, k; | |
| float64_t t1, t2, r1, r2, s1, s2; | |
| /* Initializations for the fft calculation */ | |
| n2 = fftLen; | |
| n1 = n2; | |
| for (k = fftLen; k > 1U; k >>= 2U) | |
| { | |
| /* Initializations for the fft calculation */ | |
| n1 = n2; | |
| n2 >>= 2U; | |
| ia1 = 0U; | |
| /* FFT Calculation */ | |
| j = 0; | |
| do | |
| { | |
| /* index calculation for the coefficients */ | |
| ia2 = ia1 + ia1; | |
| ia3 = ia2 + ia1; | |
| co1 = pCoef[ia1 * 2U]; | |
| si1 = pCoef[(ia1 * 2U) + 1U]; | |
| co2 = pCoef[ia2 * 2U]; | |
| si2 = pCoef[(ia2 * 2U) + 1U]; | |
| co3 = pCoef[ia3 * 2U]; | |
| si3 = pCoef[(ia3 * 2U) + 1U]; | |
| /* Twiddle coefficients index modifier */ | |
| ia1 = ia1 + twidCoefModifier; | |
| i0 = j; | |
| do | |
| { | |
| /* index calculation for the input as, */ | |
| /* pSrc[i0 + 0], pSrc[i0 + fftLen/4], pSrc[i0 + fftLen/2], pSrc[i0 + 3fftLen/4] */ | |
| i1 = i0 + n2; | |
| i2 = i1 + n2; | |
| i3 = i2 + n2; | |
| /* xa + xc */ | |
| r1 = pSrc[(2U * i0)] + pSrc[(2U * i2)]; | |
| /* xa - xc */ | |
| r2 = pSrc[(2U * i0)] - pSrc[(2U * i2)]; | |
| /* ya + yc */ | |
| s1 = pSrc[(2U * i0) + 1U] + pSrc[(2U * i2) + 1U]; | |
| /* ya - yc */ | |
| s2 = pSrc[(2U * i0) + 1U] - pSrc[(2U * i2) + 1U]; | |
| /* xb + xd */ | |
| t1 = pSrc[2U * i1] + pSrc[2U * i3]; | |
| /* xa' = xa + xb + xc + xd */ | |
| pSrc[2U * i0] = r1 + t1; | |
| /* xa + xc -(xb + xd) */ | |
| r1 = r1 - t1; | |
| /* yb + yd */ | |
| t2 = pSrc[(2U * i1) + 1U] + pSrc[(2U * i3) + 1U]; | |
| /* ya' = ya + yb + yc + yd */ | |
| pSrc[(2U * i0) + 1U] = s1 + t2; | |
| /* (ya + yc) - (yb + yd) */ | |
| s1 = s1 - t2; | |
| /* (yb - yd) */ | |
| t1 = pSrc[(2U * i1) + 1U] - pSrc[(2U * i3) + 1U]; | |
| /* (xb - xd) */ | |
| t2 = pSrc[2U * i1] - pSrc[2U * i3]; | |
| /* xc' = (xa-xb+xc-xd)co2 + (ya-yb+yc-yd)(si2) */ | |
| pSrc[2U * i1] = (r1 * co2) + (s1 * si2); | |
| /* yc' = (ya-yb+yc-yd)co2 - (xa-xb+xc-xd)(si2) */ | |
| pSrc[(2U * i1) + 1U] = (s1 * co2) - (r1 * si2); | |
| /* (xa - xc) + (yb - yd) */ | |
| r1 = r2 + t1; | |
| /* (xa - xc) - (yb - yd) */ | |
| r2 = r2 - t1; | |
| /* (ya - yc) - (xb - xd) */ | |
| s1 = s2 - t2; | |
| /* (ya - yc) + (xb - xd) */ | |
| s2 = s2 + t2; | |
| /* xb' = (xa+yb-xc-yd)co1 + (ya-xb-yc+xd)(si1) */ | |
| pSrc[2U * i2] = (r1 * co1) + (s1 * si1); | |
| /* yb' = (ya-xb-yc+xd)co1 - (xa+yb-xc-yd)(si1) */ | |
| pSrc[(2U * i2) + 1U] = (s1 * co1) - (r1 * si1); | |
| /* xd' = (xa-yb-xc+yd)co3 + (ya+xb-yc-xd)(si3) */ | |
| pSrc[2U * i3] = (r2 * co3) + (s2 * si3); | |
| /* yd' = (ya+xb-yc-xd)co3 - (xa-yb-xc+yd)(si3) */ | |
| pSrc[(2U * i3) + 1U] = (s2 * co3) - (r2 * si3); | |
| i0 += n1; | |
| } while ( i0 < fftLen); | |
| j++; | |
| } while (j <= (n2 - 1U)); | |
| twidCoefModifier <<= 2U; | |
| } | |
| } | |
| /* | |
| * @brief Core function for the Double Precision floating-point CFFT butterfly process. | |
| * @param[in, out] *pSrc points to the in-place buffer of F64 data type. | |
| * @param[in] fftLen length of the FFT. | |
| * @param[in] *pCoef points to the twiddle coefficient buffer. | |
| * @param[in] twidCoefModifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table. | |
| * @return none. | |
| */ | |
| void arm_cfft_radix4by2_f64( | |
| float64_t * pSrc, | |
| uint32_t fftLen, | |
| const float64_t * pCoef) | |
| { | |
| uint32_t i, l; | |
| uint32_t n2, ia; | |
| float64_t xt, yt, cosVal, sinVal; | |
| float64_t p0, p1,p2,p3,a0,a1; | |
| n2 = fftLen >> 1; | |
| ia = 0; | |
| for (i = 0; i < n2; i++) | |
| { | |
| cosVal = pCoef[2*ia]; | |
| sinVal = pCoef[2*ia + 1]; | |
| ia++; | |
| l = i + n2; | |
| /* Butterfly implementation */ | |
| a0 = pSrc[2 * i] + pSrc[2 * l]; | |
| xt = pSrc[2 * i] - pSrc[2 * l]; | |
| yt = pSrc[2 * i + 1] - pSrc[2 * l + 1]; | |
| a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1]; | |
| p0 = xt * cosVal; | |
| p1 = yt * sinVal; | |
| p2 = yt * cosVal; | |
| p3 = xt * sinVal; | |
| pSrc[2 * i] = a0; | |
| pSrc[2 * i + 1] = a1; | |
| pSrc[2 * l] = p0 + p1; | |
| pSrc[2 * l + 1] = p2 - p3; | |
| } | |
| // first col | |
| arm_radix4_butterfly_f64( pSrc, n2, (float64_t*)pCoef, 2U); | |
| // second col | |
| arm_radix4_butterfly_f64( pSrc + fftLen, n2, (float64_t*)pCoef, 2U); | |
| } | |
| /** | |
| @addtogroup ComplexFFT | |
| @{ | |
| */ | |
| /** | |
| @brief Processing function for the Double Precision floating-point complex FFT. | |
| @param[in] S points to an instance of the Double Precision floating-point CFFT structure | |
| @param[in,out] p1 points to the complex data buffer of size <code>2*fftLen</code>. Processing occurs in-place | |
| @param[in] ifftFlag flag that selects transform direction | |
| - value = 0: forward transform | |
| - value = 1: inverse transform | |
| @param[in] bitReverseFlag flag that enables / disables bit reversal of output | |
| - value = 0: disables bit reversal of output | |
| - value = 1: enables bit reversal of output | |
| @return none | |
| */ | |
| void arm_cfft_f64( | |
| const arm_cfft_instance_f64 * S, | |
| float64_t * p1, | |
| uint8_t ifftFlag, | |
| uint8_t bitReverseFlag) | |
| { | |
| uint32_t L = S->fftLen, l; | |
| float64_t invL, * pSrc; | |
| if (ifftFlag == 1U) | |
| { | |
| /* Conjugate input data */ | |
| pSrc = p1 + 1; | |
| for(l=0; l<L; l++) | |
| { | |
| *pSrc = -*pSrc; | |
| pSrc += 2; | |
| } | |
| } | |
| switch (L) | |
| { | |
| case 16: | |
| case 64: | |
| case 256: | |
| case 1024: | |
| case 4096: | |
| arm_radix4_butterfly_f64 (p1, L, (float64_t*)S->pTwiddle, 1U); | |
| break; | |
| case 32: | |
| case 128: | |
| case 512: | |
| case 2048: | |
| arm_cfft_radix4by2_f64 ( p1, L, (float64_t*)S->pTwiddle); | |
| break; | |
| } | |
| if ( bitReverseFlag ) | |
| arm_bitreversal_64((uint64_t*)p1, S->bitRevLength,S->pBitRevTable); | |
| if (ifftFlag == 1U) | |
| { | |
| invL = 1.0 / (float64_t)L; | |
| /* Conjugate and scale output data */ | |
| pSrc = p1; | |
| for(l=0; l<L; l++) | |
| { | |
| *pSrc++ *= invL ; | |
| *pSrc = -(*pSrc) * invL; | |
| pSrc++; | |
| } | |
| } | |
| } | |
| /** | |
| @} end of ComplexFFT group | |
| */ | |