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Rev	Author	Line No.	Line
2	mjames	1	/* ----------------------------------------------------------------------
		2	* Project: CMSIS DSP Library
		3	* Title: arm_dot_prod_q7.c
		4	* Description: Q7 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 groupMath
		33	*/
		34
		35	/**
		36	* @addtogroup dot_prod
		37	* @{
		38	*/
		39
		40	/**
		41	* @brief Dot product of Q7 vectors.
		42	* @param[in] *pSrcA points to the first input vector
		43	* @param[in] *pSrcB points to the second input vector
		44	* @param[in] blockSize number of samples in each vector
		45	* @param[out] *result output result returned here
		46	* @return none.
		47	*
		48	* <b>Scaling and Overflow Behavior:</b>
		49	* \par
		50	* The intermediate multiplications are in 1.7 x 1.7 = 2.14 format and these
		51	* results are added to an accumulator in 18.14 format.
		52	* Nonsaturating additions are used and there is no danger of wrap around as long as
		53	* the vectors are less than 2^18 elements long.
		54	* The return result is in 18.14 format.
		55	*/
		56
		57	void arm_dot_prod_q7(
		58	q7_t * pSrcA,
		59	q7_t * pSrcB,
		60	uint32_t blockSize,
		61	q31_t * result)
		62	{
		63	uint32_t blkCnt; /* loop counter */
		64
		65	q31_t sum = 0; /* Temporary variables to store output */
		66
		67	#if defined (ARM_MATH_DSP)
		68
		69	/* Run the below code for Cortex-M4 and Cortex-M3 */
		70
		71	q31_t input1, input2; /* Temporary variables to store input */
		72	q31_t inA1, inA2, inB1, inB2; /* Temporary variables to store input */
		73
		74
		75
		76	/loop Unrolling /
		77	blkCnt = blockSize >> 2U;
		78
		79	/* First part of the processing with loop unrolling. Compute 4 outputs at a time.
		80	** a second loop below computes the remaining 1 to 3 samples. */
		81	while (blkCnt > 0U)
		82	{
		83	/* read 4 samples at a time from sourceA */
		84	input1 = *__SIMD32(pSrcA)++;
		85	/* read 4 samples at a time from sourceB */
		86	input2 = *__SIMD32(pSrcB)++;
		87
		88	/* extract two q7_t samples to q15_t samples */
		89	inA1 = __SXTB16(__ROR(input1, 8));
		90	/* extract reminaing two samples */
		91	inA2 = __SXTB16(input1);
		92	/* extract two q7_t samples to q15_t samples */
		93	inB1 = __SXTB16(__ROR(input2, 8));
		94	/* extract reminaing two samples */
		95	inB2 = __SXTB16(input2);
		96
		97	/* multiply and accumulate two samples at a time */
		98	sum = __SMLAD(inA1, inB1, sum);
		99	sum = __SMLAD(inA2, inB2, sum);
		100
		101	/* Decrement the loop counter */
		102	blkCnt--;
		103	}
		104
		105	/* If the blockSize is not a multiple of 4, compute any remaining output samples here.
		106	** No loop unrolling is used. */
		107	blkCnt = blockSize % 0x4U;
		108
		109	while (blkCnt > 0U)
		110	{
		111	/* C = A[0]* B[0] + A[1]* B[1] + A[2]* B[2] + .....+ A[blockSize-1]* B[blockSize-1] */
		112	/* Dot product and then store the results in a temporary buffer. */
		113	sum = __SMLAD(pSrcA++, pSrcB++, sum);
		114
		115	/* Decrement the loop counter */
		116	blkCnt--;
		117	}
		118
		119	#else
		120
		121	/* Run the below code for Cortex-M0 */
		122
		123
		124
		125	/* Initialize blkCnt with number of samples */
		126	blkCnt = blockSize;
		127
		128	while (blkCnt > 0U)
		129	{
		130	/* C = A[0]* B[0] + A[1]* B[1] + A[2]* B[2] + .....+ A[blockSize-1]* B[blockSize-1] */
		131	/* Dot product and then store the results in a temporary buffer. */
		132	sum += (q31_t) ((q15_t) * pSrcA++ * *pSrcB++);
		133
		134	/* Decrement the loop counter */
		135	blkCnt--;
		136	}
		137
		138	#endif /* #if defined (ARM_MATH_DSP) */
		139
		140
		141	/* Store the result in the destination buffer in 18.14 format */
		142	*result = sum;
		143	}
		144
		145	/**
		146	* @} end of dot_prod group
		147	*/

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(root)/trunk/Drivers/CMSIS/DSP/Source/BasicMathFunctions/arm_dot_prod_q7.c – Rev 2