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/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_cmplx_mult_cmplx_q15.c
* Description: Q15 complex-by-complex multiplication
*
* $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 CmplxByCmplxMult
@{
*/
/**
@brief Q15 complex-by-complex multiplication.
@param[in] pSrcA points to first input vector
@param[in] pSrcB points to second input vector
@param[out] pDst points to output vector
@param[in] numSamples number of samples in each vector
@return none
@par Scaling and Overflow Behavior
The function implements 1.15 by 1.15 multiplications and finally output is converted into 3.13 format.
*/
void arm_cmplx_mult_cmplx_q15(
const q15_t * pSrcA,
const q15_t * pSrcB,
q15_t * pDst,
uint32_t numSamples)
{
uint32_t blkCnt; /* Loop counter */
q15_t a, b, c, d; /* Temporary variables */
#if defined (ARM_MATH_LOOPUNROLL)
/* Loop unrolling: Compute 4 outputs at a time */
blkCnt = numSamples >> 2U;
while (blkCnt > 0U)
{
/* C[2 * i ] = A[2 * i] * B[2 * i ] - A[2 * i + 1] * B[2 * i + 1]. */
/* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i ]. */
a = *pSrcA++;
b = *pSrcA++;
c = *pSrcB++;
d = *pSrcB++;
/* store result in 3.13 format in destination buffer. */
*pDst++ = (q15_t) ( (((q31_t) a * c) >> 17) - (((q31_t) b * d) >> 17) );
*pDst++ = (q15_t) ( (((q31_t) a * d) >> 17) + (((q31_t) b * c) >> 17) );
a = *pSrcA++;
b = *pSrcA++;
c = *pSrcB++;
d = *pSrcB++;
*pDst++ = (q15_t) ( (((q31_t) a * c) >> 17) - (((q31_t) b * d) >> 17) );
*pDst++ = (q15_t) ( (((q31_t) a * d) >> 17) + (((q31_t) b * c) >> 17) );
a = *pSrcA++;
b = *pSrcA++;
c = *pSrcB++;
d = *pSrcB++;
*pDst++ = (q15_t) ( (((q31_t) a * c) >> 17) - (((q31_t) b * d) >> 17) );
*pDst++ = (q15_t) ( (((q31_t) a * d) >> 17) + (((q31_t) b * c) >> 17) );
a = *pSrcA++;
b = *pSrcA++;
c = *pSrcB++;
d = *pSrcB++;
*pDst++ = (q15_t) ( (((q31_t) a * c) >> 17) - (((q31_t) b * d) >> 17) );
*pDst++ = (q15_t) ( (((q31_t) a * d) >> 17) + (((q31_t) b * c) >> 17) );
/* 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)
{
/* C[2 * i ] = A[2 * i] * B[2 * i ] - A[2 * i + 1] * B[2 * i + 1]. */
/* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i ]. */
a = *pSrcA++;
b = *pSrcA++;
c = *pSrcB++;
d = *pSrcB++;
/* store result in 3.13 format in destination buffer. */
*pDst++ = (q15_t) ( (((q31_t) a * c) >> 17) - (((q31_t) b * d) >> 17) );
*pDst++ = (q15_t) ( (((q31_t) a * d) >> 17) + (((q31_t) b * c) >> 17) );
/* Decrement loop counter */
blkCnt--;
}
}
/**
@} end of CmplxByCmplxMult group
*/
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