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/* ----------------------------------------------------------------------
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* Copyright (C) 2010 ARM Limited. All rights reserved.
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*
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* $Date: 29. November 2010
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* $Revision: V1.0.3
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*
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* Project: CMSIS DSP Library
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* Title: arm_cmplx_mult_cmplx_q15.c
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*
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* Description: Q15 complex-by-complex multiplication
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*
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* Target Processor: Cortex-M4/Cortex-M3
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*
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* Version 1.0.3 2010/11/29
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* Re-organized the CMSIS folders and updated documentation.
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*
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* Version 1.0.2 2010/11/11
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* Documentation updated.
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*
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* Version 1.0.1 2010/10/05
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* Production release and review comments incorporated.
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*
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* Version 1.0.0 2010/09/20
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* Production release and review comments incorporated.
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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 CmplxByCmplxMult
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* @{
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*/
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/**
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* @brief Q15 complex-by-complex multiplication
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* @param[in] *pSrcA points to the first input vector
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* @param[in] *pSrcB points to the second input vector
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* @param[out] *pDst points to the output vector
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* @param[in] numSamples number of complex samples in each vector
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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 implements 1.15 by 1.15 multiplications and finally output is converted into 3.13 format.
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*/
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void arm_cmplx_mult_cmplx_q15(
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q15_t * pSrcA,
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q15_t * pSrcB,
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q15_t * pDst,
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uint32_t numSamples)
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{
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q15_t a, b, c, d; /* Temporary variables to store real and imaginary values */
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uint32_t blkCnt; /* loop counters */
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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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/* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1]. */
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/* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i]. */
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a = *pSrcA++;
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b = *pSrcA++;
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c = *pSrcB++;
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d = *pSrcB++;
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/* store the result in 3.13 format in the destination buffer. */
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*pDst++ =
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(q15_t) (q31_t) (((q31_t) a * c) >> 17) - (((q31_t) b * d) >> 17);
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/* store the result in 3.13 format in the destination buffer. */
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*pDst++ =
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(q15_t) (q31_t) (((q31_t) a * d) >> 17) + (((q31_t) b * c) >> 17);
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a = *pSrcA++;
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b = *pSrcA++;
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c = *pSrcB++;
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d = *pSrcB++;
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/* store the result in 3.13 format in the destination buffer. */
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*pDst++ =
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(q15_t) (q31_t) (((q31_t) a * c) >> 17) - (((q31_t) b * d) >> 17);
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/* store the result in 3.13 format in the destination buffer. */
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*pDst++ =
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(q15_t) (q31_t) (((q31_t) a * d) >> 17) + (((q31_t) b * c) >> 17);
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a = *pSrcA++;
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b = *pSrcA++;
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c = *pSrcB++;
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d = *pSrcB++;
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/* store the result in 3.13 format in the destination buffer. */
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*pDst++ =
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(q15_t) (q31_t) (((q31_t) a * c) >> 17) - (((q31_t) b * d) >> 17);
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/* store the result in 3.13 format in the destination buffer. */
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*pDst++ =
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(q15_t) (q31_t) (((q31_t) a * d) >> 17) + (((q31_t) b * c) >> 17);
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a = *pSrcA++;
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b = *pSrcA++;
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c = *pSrcB++;
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d = *pSrcB++;
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/* store the result in 3.13 format in the destination buffer. */
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*pDst++ =
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(q15_t) (q31_t) (((q31_t) a * c) >> 17) - (((q31_t) b * d) >> 17);
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/* store the result in 3.13 format in the destination buffer. */
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*pDst++ =
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(q15_t) (q31_t) (((q31_t) a * d) >> 17) + (((q31_t) b * c) >> 17);
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/* Decrement the blockSize loop counter */
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blkCnt--;
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}
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/* If the blockSize 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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/* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1]. */
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/* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i]. */
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a = *pSrcA++;
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b = *pSrcA++;
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c = *pSrcB++;
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d = *pSrcB++;
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/* store the result in 3.13 format in the destination buffer. */
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*pDst++ =
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(q15_t) (q31_t) (((q31_t) a * c) >> 17) - (((q31_t) b * d) >> 17);
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/* store the result in 3.13 format in the destination buffer. */
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*pDst++ =
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(q15_t) (q31_t) (((q31_t) a * d) >> 17) + (((q31_t) b * c) >> 17);
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/* Decrement the blockSize loop counter */
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blkCnt--;
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}
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}
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/**
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* @} end of CmplxByCmplxMult group
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*/
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