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