253 lines
6.1 KiB
C
253 lines
6.1 KiB
C
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/* ----------------------------------------------------------------------
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* Project: CMSIS DSP Library
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* Title: arm_cfft_q31.c
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* Description: Combined Radix Decimation in Frequency CFFT 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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extern void arm_radix4_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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uint32_t twidCoefModifier);
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extern void arm_radix4_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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uint32_t twidCoefModifier);
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extern void arm_bitreversal_32(
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uint32_t * pSrc,
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const uint16_t bitRevLen,
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const uint16_t * pBitRevTable);
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void arm_cfft_radix4by2_q31(
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q31_t * pSrc,
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uint32_t fftLen,
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const q31_t * pCoef);
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void arm_cfft_radix4by2_inverse_q31(
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q31_t * pSrc,
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uint32_t fftLen,
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const q31_t * pCoef);
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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 complex FFT in Q31 format.
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* @param[in] *S points to an instance of the fixed-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 forward (ifftFlag=0) or inverse (ifftFlag=1) transform.
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* @param[in] bitReverseFlag flag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output.
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* @return none.
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*/
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void arm_cfft_q31(
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const arm_cfft_instance_q31 * S,
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q31_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;
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if (ifftFlag == 1U)
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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_inverse_q31 ( p1, L, (q31_t*)S->pTwiddle, 1 );
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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_inverse_q31 ( p1, L, S->pTwiddle );
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break;
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}
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}
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else
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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_q31 ( p1, L, (q31_t*)S->pTwiddle, 1 );
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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_q31 ( p1, L, S->pTwiddle );
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break;
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}
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}
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if ( bitReverseFlag )
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arm_bitreversal_32((uint32_t*)p1,S->bitRevLength,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_cfft_radix4by2_q31(
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q31_t * pSrc,
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uint32_t fftLen,
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const q31_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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q31_t xt, yt, cosVal, sinVal;
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q31_t p0, p1;
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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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xt = (pSrc[2 * i] >> 2) - (pSrc[2 * l] >> 2);
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pSrc[2 * i] = (pSrc[2 * i] >> 2) + (pSrc[2 * l] >> 2);
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yt = (pSrc[2 * i + 1] >> 2) - (pSrc[2 * l + 1] >> 2);
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pSrc[2 * i + 1] = (pSrc[2 * l + 1] >> 2) + (pSrc[2 * i + 1] >> 2);
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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 << 1;
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pSrc[2U * l + 1U] = p1 << 1;
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}
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// first col
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arm_radix4_butterfly_q31( pSrc, n2, (q31_t*)pCoef, 2U);
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// second col
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arm_radix4_butterfly_q31( pSrc + fftLen, n2, (q31_t*)pCoef, 2U);
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for (i = 0; i < fftLen >> 1; i++)
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{
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p0 = pSrc[4*i+0];
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p1 = pSrc[4*i+1];
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xt = pSrc[4*i+2];
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yt = pSrc[4*i+3];
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p0 <<= 1;
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p1 <<= 1;
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xt <<= 1;
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yt <<= 1;
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pSrc[4*i+0] = p0;
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pSrc[4*i+1] = p1;
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pSrc[4*i+2] = xt;
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pSrc[4*i+3] = yt;
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}
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}
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void arm_cfft_radix4by2_inverse_q31(
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q31_t * pSrc,
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uint32_t fftLen,
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const q31_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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q31_t xt, yt, cosVal, sinVal;
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q31_t p0, p1;
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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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xt = (pSrc[2 * i] >> 2) - (pSrc[2 * l] >> 2);
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pSrc[2 * i] = (pSrc[2 * i] >> 2) + (pSrc[2 * l] >> 2);
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yt = (pSrc[2 * i + 1] >> 2) - (pSrc[2 * l + 1] >> 2);
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pSrc[2 * i + 1] = (pSrc[2 * l + 1] >> 2) + (pSrc[2 * i + 1] >> 2);
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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 << 1;
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pSrc[2U * l + 1U] = p1 << 1;
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}
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// first col
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arm_radix4_butterfly_inverse_q31( pSrc, n2, (q31_t*)pCoef, 2U);
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// second col
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arm_radix4_butterfly_inverse_q31( pSrc + fftLen, n2, (q31_t*)pCoef, 2U);
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for (i = 0; i < fftLen >> 1; i++)
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{
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p0 = pSrc[4*i+0];
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p1 = pSrc[4*i+1];
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xt = pSrc[4*i+2];
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yt = pSrc[4*i+3];
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p0 <<= 1;
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p1 <<= 1;
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xt <<= 1;
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yt <<= 1;
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pSrc[4*i+0] = p0;
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pSrc[4*i+1] = p1;
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pSrc[4*i+2] = xt;
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pSrc[4*i+3] = yt;
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}
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}
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