/* ----------------------------------------------------------------------
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* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
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*
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* $Date: 19. March 2015
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* $Revision: V.1.4.5
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*
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* Project: CMSIS DSP Library
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* Title: arm_cfft_radix2_q31.c
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*
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* Description: Radix-2 Decimation in Frequency CFFT & CIFFT Fixed point processing function
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*
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*
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* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* - Neither the name of ARM LIMITED nor the names of its contributors
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* may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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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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