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/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_cmplx_dot_prod_q15.c
* Description: Processing function for the Q15 Complex Dot product
*
* $Date: 18. March 2019
* $Revision: V1.6.0
*
* Target Processor: Cortex-M cores
* -------------------------------------------------------------------- */
/*
* Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved.
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the License); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an AS IS BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "arm_math.h"
/**
@ingroup groupCmplxMath
*/
/**
@addtogroup cmplx_dot_prod
@{
*/
/**
@brief Q15 complex dot product.
@param[in] pSrcA points to the first input vector
@param[in] pSrcB points to the second input vector
@param[in] numSamples number of samples in each vector
@param[out] realResult real part of the result returned here
@param[out] imagResult imaginary part of the result returned her
@return none
@par Scaling and Overflow Behavior
The function is implemented using an internal 64-bit accumulator.
The intermediate 1.15 by 1.15 multiplications are performed with full precision and yield a 2.30 result.
These are accumulated in a 64-bit accumulator with 34.30 precision.
As a final step, the accumulators are converted to 8.24 format.
The return results <code>realResult</code> and <code>imagResult</code> are in 8.24 format.
*/
void arm_cmplx_dot_prod_q15(
const q15_t * pSrcA,
const q15_t * pSrcB,
uint32_t numSamples,
q31_t * realResult,
q31_t * imagResult)
{
uint32_t blkCnt; /* Loop counter */
q63_t real_sum = 0, imag_sum = 0; /* Temporary result variables */
q15_t a0,b0,c0,d0;
#if defined (ARM_MATH_LOOPUNROLL)
/* Loop unrolling: Compute 4 outputs at a time */
blkCnt = numSamples >> 2U;
while (blkCnt > 0U)
{
a0 = *pSrcA++;
b0 = *pSrcA++;
c0 = *pSrcB++;
d0 = *pSrcB++;
real_sum += (q31_t)a0 * c0;
imag_sum += (q31_t)a0 * d0;
real_sum -= (q31_t)b0 * d0;
imag_sum += (q31_t)b0 * c0;
a0 = *pSrcA++;
b0 = *pSrcA++;
c0 = *pSrcB++;
d0 = *pSrcB++;
real_sum += (q31_t)a0 * c0;
imag_sum += (q31_t)a0 * d0;
real_sum -= (q31_t)b0 * d0;
imag_sum += (q31_t)b0 * c0;
a0 = *pSrcA++;
b0 = *pSrcA++;
c0 = *pSrcB++;
d0 = *pSrcB++;
real_sum += (q31_t)a0 * c0;
imag_sum += (q31_t)a0 * d0;
real_sum -= (q31_t)b0 * d0;
imag_sum += (q31_t)b0 * c0;
a0 = *pSrcA++;
b0 = *pSrcA++;
c0 = *pSrcB++;
d0 = *pSrcB++;
real_sum += (q31_t)a0 * c0;
imag_sum += (q31_t)a0 * d0;
real_sum -= (q31_t)b0 * d0;
imag_sum += (q31_t)b0 * c0;
/* Decrement loop counter */
blkCnt--;
}
/* Loop unrolling: Compute remaining outputs */
blkCnt = numSamples % 0x4U;
#else
/* Initialize blkCnt with number of samples */
blkCnt = numSamples;
#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
while (blkCnt > 0U)
{
a0 = *pSrcA++;
b0 = *pSrcA++;
c0 = *pSrcB++;
d0 = *pSrcB++;
real_sum += (q31_t)a0 * c0;
imag_sum += (q31_t)a0 * d0;
real_sum -= (q31_t)b0 * d0;
imag_sum += (q31_t)b0 * c0;
/* Decrement loop counter */
blkCnt--;
}
/* Store real and imaginary result in 8.24 format */
/* Convert real data in 34.30 to 8.24 by 6 right shifts */
*realResult = (q31_t) (real_sum >> 6);
/* Convert imaginary data in 34.30 to 8.24 by 6 right shifts */
*imagResult = (q31_t) (imag_sum >> 6);
}
/**
@} end of cmplx_dot_prod group
*/
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