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Rev	Author	Line No.	Line
2	mjames	1	/* ----------------------------------------------------------------------
		2	* Project: CMSIS DSP Library
		3	* Title: arm_cmplx_dot_prod_q15.c
		4	* Description: Processing function for the Q15 Complex Dot product
		5	*
		6	* $Date: 27. January 2017
		7	* $Revision: V.1.5.1
		8	*
		9	* Target Processor: Cortex-M cores
		10	* -------------------------------------------------------------------- */
		11	/*
		12	* Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
		13	*
		14	* SPDX-License-Identifier: Apache-2.0
		15	*
		16	* Licensed under the Apache License, Version 2.0 (the License); you may
		17	* not use this file except in compliance with the License.
		18	* You may obtain a copy of the License at
		19	*
		20	* www.apache.org/licenses/LICENSE-2.0
		21	*
		22	* Unless required by applicable law or agreed to in writing, software
		23	* distributed under the License is distributed on an AS IS BASIS, WITHOUT
		24	* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		25	* See the License for the specific language governing permissions and
		26	* limitations under the License.
		27	*/
		28
		29	#include "arm_math.h"
		30
		31	/**
		32	* @ingroup groupCmplxMath
		33	*/
		34
		35	/**
		36	* @addtogroup cmplx_dot_prod
		37	* @{
		38	*/
		39
		40	/**
		41	* @brief Q15 complex dot product
		42	* @param *pSrcA points to the first input vector
		43	* @param *pSrcB points to the second input vector
		44	* @param numSamples number of complex samples in each vector
		45	* @param *realResult real part of the result returned here
		46	* @param *imagResult imaginary part of the result returned here
		47	* @return none.
		48	*
		49	* <b>Scaling and Overflow Behavior:</b>
		50	* \par
		51	* The function is implemented using an internal 64-bit accumulator.
		52	* The intermediate 1.15 by 1.15 multiplications are performed with full precision and yield a 2.30 result.
		53	* These are accumulated in a 64-bit accumulator with 34.30 precision.
		54	* As a final step, the accumulators are converted to 8.24 format.
		55	* The return results <code>realResult</code> and <code>imagResult</code> are in 8.24 format.
		56	*/
		57
		58	void arm_cmplx_dot_prod_q15(
		59	q15_t * pSrcA,
		60	q15_t * pSrcB,
		61	uint32_t numSamples,
		62	q31_t * realResult,
		63	q31_t * imagResult)
		64	{
		65	q63_t real_sum = 0, imag_sum = 0; /* Temporary result storage */
		66	q15_t a0,b0,c0,d0;
		67
		68	#if defined (ARM_MATH_DSP)
		69
		70	/* Run the below code for Cortex-M4 and Cortex-M3 */
		71	uint32_t blkCnt; /* loop counter */
		72
		73
		74	/loop Unrolling /
		75	blkCnt = numSamples >> 2U;
		76
		77	/* First part of the processing with loop unrolling. Compute 4 outputs at a time.
		78	** a second loop below computes the remaining 1 to 3 samples. */
		79	while (blkCnt > 0U)
		80	{
		81	a0 = *pSrcA++;
		82	b0 = *pSrcA++;
		83	c0 = *pSrcB++;
		84	d0 = *pSrcB++;
		85
		86	real_sum += (q31_t)a0 * c0;
		87	imag_sum += (q31_t)a0 * d0;
		88	real_sum -= (q31_t)b0 * d0;
		89	imag_sum += (q31_t)b0 * c0;
		90
		91	a0 = *pSrcA++;
		92	b0 = *pSrcA++;
		93	c0 = *pSrcB++;
		94	d0 = *pSrcB++;
		95
		96	real_sum += (q31_t)a0 * c0;
		97	imag_sum += (q31_t)a0 * d0;
		98	real_sum -= (q31_t)b0 * d0;
		99	imag_sum += (q31_t)b0 * c0;
		100
		101	a0 = *pSrcA++;
		102	b0 = *pSrcA++;
		103	c0 = *pSrcB++;
		104	d0 = *pSrcB++;
		105
		106	real_sum += (q31_t)a0 * c0;
		107	imag_sum += (q31_t)a0 * d0;
		108	real_sum -= (q31_t)b0 * d0;
		109	imag_sum += (q31_t)b0 * c0;
		110
		111	a0 = *pSrcA++;
		112	b0 = *pSrcA++;
		113	c0 = *pSrcB++;
		114	d0 = *pSrcB++;
		115
		116	real_sum += (q31_t)a0 * c0;
		117	imag_sum += (q31_t)a0 * d0;
		118	real_sum -= (q31_t)b0 * d0;
		119	imag_sum += (q31_t)b0 * c0;
		120
		121	/* Decrement the loop counter */
		122	blkCnt--;
		123	}
		124
		125	/* If the numSamples is not a multiple of 4, compute any remaining output samples here.
		126	** No loop unrolling is used. */
		127	blkCnt = numSamples % 0x4U;
		128
		129	while (blkCnt > 0U)
		130	{
		131	a0 = *pSrcA++;
		132	b0 = *pSrcA++;
		133	c0 = *pSrcB++;
		134	d0 = *pSrcB++;
		135
		136	real_sum += (q31_t)a0 * c0;
		137	imag_sum += (q31_t)a0 * d0;
		138	real_sum -= (q31_t)b0 * d0;
		139	imag_sum += (q31_t)b0 * c0;
		140
		141	/* Decrement the loop counter */
		142	blkCnt--;
		143	}
		144
		145	#else
		146
		147	/* Run the below code for Cortex-M0 */
		148
		149	while (numSamples > 0U)
		150	{
		151	a0 = *pSrcA++;
		152	b0 = *pSrcA++;
		153	c0 = *pSrcB++;
		154	d0 = *pSrcB++;
		155
		156	real_sum += a0 * c0;
		157	imag_sum += a0 * d0;
		158	real_sum -= b0 * d0;
		159	imag_sum += b0 * c0;
		160
		161
		162	/* Decrement the loop counter */
		163	numSamples--;
		164	}
		165
		166	#endif /* #if defined (ARM_MATH_DSP) */
		167
		168	/* Store the real and imaginary results in 8.24 format */
		169	/* Convert real data in 34.30 to 8.24 by 6 right shifts */
		170	*realResult = (q31_t) (real_sum >> 6);
		171	/* Convert imaginary data in 34.30 to 8.24 by 6 right shifts */
		172	*imagResult = (q31_t) (imag_sum >> 6);
		173	}
		174
		175	/**
		176	* @} end of cmplx_dot_prod group
		177	*/

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