/* ----------------------------------------------------------------------
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* Project: CMSIS DSP Library
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* Title: arm_cmplx_dot_prod_q15.c
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* Description: Processing function for the Q15 Complex Dot product
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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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/**
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* @ingroup groupCmplxMath
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*/
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/**
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* @addtogroup cmplx_dot_prod
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* @{
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*/
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/**
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* @brief Q15 complex dot product
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* @param *pSrcA points to the first input vector
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* @param *pSrcB points to the second input vector
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* @param numSamples number of complex samples in each vector
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* @param *realResult real part of the result returned here
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* @param *imagResult imaginary part of the result returned here
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* @return none.
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*
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* <b>Scaling and Overflow Behavior:</b>
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* \par
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* The function is implemented using an internal 64-bit accumulator.
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* The intermediate 1.15 by 1.15 multiplications are performed with full precision and yield a 2.30 result.
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* These are accumulated in a 64-bit accumulator with 34.30 precision.
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* As a final step, the accumulators are converted to 8.24 format.
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* The return results <code>realResult</code> and <code>imagResult</code> are in 8.24 format.
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*/
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void arm_cmplx_dot_prod_q15(
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q15_t * pSrcA,
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q15_t * pSrcB,
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uint32_t numSamples,
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q31_t * realResult,
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q31_t * imagResult)
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{
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q63_t real_sum = 0, imag_sum = 0; /* Temporary result storage */
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q15_t a0,b0,c0,d0;
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#if defined (ARM_MATH_DSP)
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/* Run the below code for Cortex-M4 and Cortex-M3 */
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uint32_t blkCnt; /* loop counter */
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/*loop Unrolling */
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blkCnt = numSamples >> 2U;
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/* First part of the processing with loop unrolling. Compute 4 outputs at a time.
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** a second loop below computes the remaining 1 to 3 samples. */
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while (blkCnt > 0U)
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{
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a0 = *pSrcA++;
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b0 = *pSrcA++;
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c0 = *pSrcB++;
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d0 = *pSrcB++;
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real_sum += (q31_t)a0 * c0;
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imag_sum += (q31_t)a0 * d0;
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real_sum -= (q31_t)b0 * d0;
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imag_sum += (q31_t)b0 * c0;
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a0 = *pSrcA++;
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b0 = *pSrcA++;
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c0 = *pSrcB++;
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d0 = *pSrcB++;
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real_sum += (q31_t)a0 * c0;
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imag_sum += (q31_t)a0 * d0;
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real_sum -= (q31_t)b0 * d0;
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imag_sum += (q31_t)b0 * c0;
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a0 = *pSrcA++;
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b0 = *pSrcA++;
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c0 = *pSrcB++;
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d0 = *pSrcB++;
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real_sum += (q31_t)a0 * c0;
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imag_sum += (q31_t)a0 * d0;
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real_sum -= (q31_t)b0 * d0;
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imag_sum += (q31_t)b0 * c0;
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a0 = *pSrcA++;
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b0 = *pSrcA++;
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c0 = *pSrcB++;
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d0 = *pSrcB++;
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real_sum += (q31_t)a0 * c0;
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imag_sum += (q31_t)a0 * d0;
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real_sum -= (q31_t)b0 * d0;
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imag_sum += (q31_t)b0 * c0;
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/* Decrement the loop counter */
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blkCnt--;
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}
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/* If the numSamples is not a multiple of 4, compute any remaining output samples here.
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** No loop unrolling is used. */
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blkCnt = numSamples % 0x4U;
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while (blkCnt > 0U)
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{
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a0 = *pSrcA++;
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b0 = *pSrcA++;
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c0 = *pSrcB++;
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d0 = *pSrcB++;
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real_sum += (q31_t)a0 * c0;
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imag_sum += (q31_t)a0 * d0;
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real_sum -= (q31_t)b0 * d0;
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imag_sum += (q31_t)b0 * c0;
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/* Decrement the loop counter */
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blkCnt--;
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}
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#else
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/* Run the below code for Cortex-M0 */
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while (numSamples > 0U)
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{
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a0 = *pSrcA++;
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b0 = *pSrcA++;
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c0 = *pSrcB++;
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d0 = *pSrcB++;
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real_sum += a0 * c0;
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imag_sum += a0 * d0;
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real_sum -= b0 * d0;
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imag_sum += b0 * c0;
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/* Decrement the loop counter */
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numSamples--;
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}
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#endif /* #if defined (ARM_MATH_DSP) */
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/* Store the real and imaginary results in 8.24 format */
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/* Convert real data in 34.30 to 8.24 by 6 right shifts */
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*realResult = (q31_t) (real_sum >> 6);
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/* Convert imaginary data in 34.30 to 8.24 by 6 right shifts */
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*imagResult = (q31_t) (imag_sum >> 6);
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}
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/**
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* @} end of cmplx_dot_prod group
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*/
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