/* ----------------------------------------------------------------------
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* Project: CMSIS DSP Library
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* Title: arm_cfft_radix2_q31.c
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* Description: Radix-2 Decimation in Frequency CFFT & CIFFT Fixed point processing function
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*
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* $Date: 27. January 2017
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* $Revision: V.1.5.1
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*
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* Target Processor: Cortex-M cores
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* -------------------------------------------------------------------- */
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/*
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* Copyright (C) 2010-2017 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 "arm_math.h"
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void arm_radix2_butterfly_q31(
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q31_t * pSrc,
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uint32_t fftLen,
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q31_t * pCoef,
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uint16_t twidCoefModifier);
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void arm_radix2_butterfly_inverse_q31(
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q31_t * pSrc,
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uint32_t fftLen,
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q31_t * pCoef,
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uint16_t twidCoefModifier);
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void arm_bitreversal_q31(
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q31_t * pSrc,
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uint32_t fftLen,
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uint16_t bitRevFactor,
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uint16_t * pBitRevTab);
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/**
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* @ingroup groupTransforms
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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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* @details
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* @brief Processing function for the fixed-point CFFT/CIFFT.
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* @deprecated Do not use this function. It has been superseded by \ref arm_cfft_q31 and will be removed
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* @param[in] *S points to an instance of the fixed-point CFFT/CIFFT structure.
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* @param[in, out] *pSrc points to the complex data buffer of size <code>2*fftLen</code>. Processing occurs in-place.
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* @return none.
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*/
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void arm_cfft_radix2_q31(
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const arm_cfft_radix2_instance_q31 * S,
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q31_t * pSrc)
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{
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if (S->ifftFlag == 1U)
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{
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arm_radix2_butterfly_inverse_q31(pSrc, S->fftLen,
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S->pTwiddle, S->twidCoefModifier);
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}
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else
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{
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arm_radix2_butterfly_q31(pSrc, S->fftLen,
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S->pTwiddle, S->twidCoefModifier);
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}
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arm_bitreversal_q31(pSrc, S->fftLen, S->bitRevFactor, S->pBitRevTable);
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}
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/**
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* @} end of ComplexFFT group
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*/
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void arm_radix2_butterfly_q31(
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q31_t * pSrc,
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uint32_t fftLen,
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q31_t * pCoef,
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uint16_t twidCoefModifier)
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{
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unsigned i, j, k, l, m;
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unsigned n1, n2, ia;
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q31_t xt, yt, cosVal, sinVal;
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q31_t p0, p1;
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//N = fftLen;
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n2 = fftLen;
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n1 = n2;
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n2 = n2 >> 1;
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ia = 0;
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// loop for groups
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for (i = 0; i < n2; i++)
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{
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cosVal = pCoef[ia * 2];
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sinVal = pCoef[(ia * 2) + 1];
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ia = ia + twidCoefModifier;
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l = i + n2;
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xt = (pSrc[2 * i] >> 1U) - (pSrc[2 * l] >> 1U);
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pSrc[2 * i] = ((pSrc[2 * i] >> 1U) + (pSrc[2 * l] >> 1U)) >> 1U;
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yt = (pSrc[2 * i + 1] >> 1U) - (pSrc[2 * l + 1] >> 1U);
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pSrc[2 * i + 1] =
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((pSrc[2 * l + 1] >> 1U) + (pSrc[2 * i + 1] >> 1U)) >> 1U;
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mult_32x32_keep32_R(p0, xt, cosVal);
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mult_32x32_keep32_R(p1, yt, cosVal);
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multAcc_32x32_keep32_R(p0, yt, sinVal);
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multSub_32x32_keep32_R(p1, xt, sinVal);
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pSrc[2U * l] = p0;
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pSrc[2U * l + 1U] = p1;
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} // groups loop end
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twidCoefModifier <<= 1U;
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// loop for stage
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for (k = fftLen / 2; k > 2; k = k >> 1)
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{
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n1 = n2;
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n2 = n2 >> 1;
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ia = 0;
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// loop for groups
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for (j = 0; j < n2; j++)
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{
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cosVal = pCoef[ia * 2];
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sinVal = pCoef[(ia * 2) + 1];
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ia = ia + twidCoefModifier;
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// loop for butterfly
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i = j;
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m = fftLen / n1;
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do
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{
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l = i + n2;
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xt = pSrc[2 * i] - pSrc[2 * l];
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pSrc[2 * i] = (pSrc[2 * i] + pSrc[2 * l]) >> 1U;
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yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];
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pSrc[2 * i + 1] = (pSrc[2 * l + 1] + pSrc[2 * i + 1]) >> 1U;
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mult_32x32_keep32_R(p0, xt, cosVal);
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mult_32x32_keep32_R(p1, yt, cosVal);
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multAcc_32x32_keep32_R(p0, yt, sinVal);
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multSub_32x32_keep32_R(p1, xt, sinVal);
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pSrc[2U * l] = p0;
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pSrc[2U * l + 1U] = p1;
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i += n1;
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m--;
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} while ( m > 0); // butterfly loop end
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} // groups loop end
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twidCoefModifier <<= 1U;
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} // stages loop end
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n1 = n2;
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n2 = n2 >> 1;
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ia = 0;
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cosVal = pCoef[ia * 2];
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sinVal = pCoef[(ia * 2) + 1];
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ia = ia + twidCoefModifier;
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// loop for butterfly
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for (i = 0; i < fftLen; i += n1)
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{
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l = i + n2;
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xt = pSrc[2 * i] - pSrc[2 * l];
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pSrc[2 * i] = (pSrc[2 * i] + pSrc[2 * l]);
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yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];
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pSrc[2 * i + 1] = (pSrc[2 * l + 1] + pSrc[2 * i + 1]);
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pSrc[2U * l] = xt;
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pSrc[2U * l + 1U] = yt;
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i += n1;
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l = i + n2;
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xt = pSrc[2 * i] - pSrc[2 * l];
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pSrc[2 * i] = (pSrc[2 * i] + pSrc[2 * l]);
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yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];
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pSrc[2 * i + 1] = (pSrc[2 * l + 1] + pSrc[2 * i + 1]);
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pSrc[2U * l] = xt;
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pSrc[2U * l + 1U] = yt;
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} // butterfly loop end
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}
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void arm_radix2_butterfly_inverse_q31(
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q31_t * pSrc,
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uint32_t fftLen,
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q31_t * pCoef,
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uint16_t twidCoefModifier)
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{
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unsigned i, j, k, l;
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unsigned n1, n2, ia;
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q31_t xt, yt, cosVal, sinVal;
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q31_t p0, p1;
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//N = fftLen;
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n2 = fftLen;
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n1 = n2;
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n2 = n2 >> 1;
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ia = 0;
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// loop for groups
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for (i = 0; i < n2; i++)
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{
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cosVal = pCoef[ia * 2];
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sinVal = pCoef[(ia * 2) + 1];
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ia = ia + twidCoefModifier;
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l = i + n2;
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xt = (pSrc[2 * i] >> 1U) - (pSrc[2 * l] >> 1U);
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pSrc[2 * i] = ((pSrc[2 * i] >> 1U) + (pSrc[2 * l] >> 1U)) >> 1U;
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yt = (pSrc[2 * i + 1] >> 1U) - (pSrc[2 * l + 1] >> 1U);
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pSrc[2 * i + 1] =
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((pSrc[2 * l + 1] >> 1U) + (pSrc[2 * i + 1] >> 1U)) >> 1U;
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mult_32x32_keep32_R(p0, xt, cosVal);
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mult_32x32_keep32_R(p1, yt, cosVal);
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multSub_32x32_keep32_R(p0, yt, sinVal);
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multAcc_32x32_keep32_R(p1, xt, sinVal);
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pSrc[2U * l] = p0;
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pSrc[2U * l + 1U] = p1;
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} // groups loop end
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twidCoefModifier = twidCoefModifier << 1U;
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// loop for stage
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for (k = fftLen / 2; k > 2; k = k >> 1)
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{
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n1 = n2;
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n2 = n2 >> 1;
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ia = 0;
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// loop for groups
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for (j = 0; j < n2; j++)
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{
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cosVal = pCoef[ia * 2];
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sinVal = pCoef[(ia * 2) + 1];
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ia = ia + twidCoefModifier;
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// loop for butterfly
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for (i = j; i < fftLen; i += n1)
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{
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l = i + n2;
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xt = pSrc[2 * i] - pSrc[2 * l];
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pSrc[2 * i] = (pSrc[2 * i] + pSrc[2 * l]) >> 1U;
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yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];
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pSrc[2 * i + 1] = (pSrc[2 * l + 1] + pSrc[2 * i + 1]) >> 1U;
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mult_32x32_keep32_R(p0, xt, cosVal);
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mult_32x32_keep32_R(p1, yt, cosVal);
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multSub_32x32_keep32_R(p0, yt, sinVal);
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multAcc_32x32_keep32_R(p1, xt, sinVal);
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pSrc[2U * l] = p0;
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pSrc[2U * l + 1U] = p1;
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} // butterfly loop end
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} // groups loop end
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twidCoefModifier = twidCoefModifier << 1U;
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} // stages loop end
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n1 = n2;
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n2 = n2 >> 1;
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ia = 0;
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cosVal = pCoef[ia * 2];
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sinVal = pCoef[(ia * 2) + 1];
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ia = ia + twidCoefModifier;
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// loop for butterfly
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for (i = 0; i < fftLen; i += n1)
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{
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l = i + n2;
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xt = pSrc[2 * i] - pSrc[2 * l];
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pSrc[2 * i] = (pSrc[2 * i] + pSrc[2 * l]);
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yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];
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pSrc[2 * i + 1] = (pSrc[2 * l + 1] + pSrc[2 * i + 1]);
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pSrc[2U * l] = xt;
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pSrc[2U * l + 1U] = yt;
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i += n1;
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l = i + n2;
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xt = pSrc[2 * i] - pSrc[2 * l];
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pSrc[2 * i] = (pSrc[2 * i] + pSrc[2 * l]);
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yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];
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pSrc[2 * i + 1] = (pSrc[2 * l + 1] + pSrc[2 * i + 1]);
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pSrc[2U * l] = xt;
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pSrc[2U * l + 1U] = yt;
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} // butterfly loop end
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}
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