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Rev	Author	Line No.	Line
2	mjames	1	/* ----------------------------------------------------------------------
		2	* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
		3	*
		4	* $Date: 19. March 2015
		5	* $Revision: V.1.4.5
		6	*
		7	* Project: CMSIS DSP Library
		8	* Title: arm_dot_prod_q15.c
		9	*
		10	* Description: Q15 dot product.
		11	*
		12	* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
		13	*
		14	* Redistribution and use in source and binary forms, with or without
		15	* modification, are permitted provided that the following conditions
		16	* are met:
		17	* - Redistributions of source code must retain the above copyright
		18	* notice, this list of conditions and the following disclaimer.
		19	* - Redistributions in binary form must reproduce the above copyright
		20	* notice, this list of conditions and the following disclaimer in
		21	* the documentation and/or other materials provided with the
		22	* distribution.
		23	* - Neither the name of ARM LIMITED nor the names of its contributors
		24	* may be used to endorse or promote products derived from this
		25	* software without specific prior written permission.
		26	*
		27	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
		28	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
		29	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
		30	* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
		31	* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
		32	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
		33	* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
		34	* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
		35	* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
		36	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
		37	* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
		38	* POSSIBILITY OF SUCH DAMAGE.
		39	* -------------------------------------------------------------------- */
		40
		41	#include "arm_math.h"
		42
		43	/**
		44	* @ingroup groupMath
		45	*/
		46
		47	/**
		48	* @addtogroup dot_prod
		49	* @{
		50	*/
		51
		52	/**
		53	* @brief Dot product of Q15 vectors.
		54	* @param[in] *pSrcA points to the first input vector
		55	* @param[in] *pSrcB points to the second input vector
		56	* @param[in] blockSize number of samples in each vector
		57	* @param[out] *result output result returned here
		58	* @return none.
		59	*
		60	* <b>Scaling and Overflow Behavior:</b>
		61	* \par
		62	* The intermediate multiplications are in 1.15 x 1.15 = 2.30 format and these
		63	* results are added to a 64-bit accumulator in 34.30 format.
		64	* Nonsaturating additions are used and given that there are 33 guard bits in the accumulator
		65	* there is no risk of overflow.
		66	* The return result is in 34.30 format.
		67	*/
		68
		69	void arm_dot_prod_q15(
		70	q15_t * pSrcA,
		71	q15_t * pSrcB,
		72	uint32_t blockSize,
		73	q63_t * result)
		74	{
		75	q63_t sum = 0; /* Temporary result storage */
		76	uint32_t blkCnt; /* loop counter */
		77
		78	#ifndef ARM_MATH_CM0_FAMILY
		79
		80	/* Run the below code for Cortex-M4 and Cortex-M3 */
		81
		82
		83	/loop Unrolling /
		84	blkCnt = blockSize >> 2u;
		85
		86	/* First part of the processing with loop unrolling. Compute 4 outputs at a time.
		87	** a second loop below computes the remaining 1 to 3 samples. */
		88	while(blkCnt > 0u)
		89	{
		90	/* C = A[0]* B[0] + A[1]* B[1] + A[2]* B[2] + .....+ A[blockSize-1]* B[blockSize-1] */
		91	/* Calculate dot product and then store the result in a temporary buffer. */
		92	sum = __SMLALD(__SIMD32(pSrcA)++, __SIMD32(pSrcB)++, sum);
		93	sum = __SMLALD(__SIMD32(pSrcA)++, __SIMD32(pSrcB)++, sum);
		94
		95	/* Decrement the loop counter */
		96	blkCnt--;
		97	}
		98
		99	/* If the blockSize is not a multiple of 4, compute any remaining output samples here.
		100	** No loop unrolling is used. */
		101	blkCnt = blockSize % 0x4u;
		102
		103	while(blkCnt > 0u)
		104	{
		105	/* C = A[0]* B[0] + A[1]* B[1] + A[2]* B[2] + .....+ A[blockSize-1]* B[blockSize-1] */
		106	/* Calculate dot product and then store the results in a temporary buffer. */
		107	sum = __SMLALD(pSrcA++, pSrcB++, sum);
		108
		109	/* Decrement the loop counter */
		110	blkCnt--;
		111	}
		112
		113
		114	#else
		115
		116	/* Run the below code for Cortex-M0 */
		117
		118	/* Initialize blkCnt with number of samples */
		119	blkCnt = blockSize;
		120
		121	while(blkCnt > 0u)
		122	{
		123	/* C = A[0]* B[0] + A[1]* B[1] + A[2]* B[2] + .....+ A[blockSize-1]* B[blockSize-1] */
		124	/* Calculate dot product and then store the results in a temporary buffer. */
		125	sum += (q63_t) ((q31_t) * pSrcA++ * *pSrcB++);
		126
		127	/* Decrement the loop counter */
		128	blkCnt--;
		129	}
		130
		131	#endif /* #ifndef ARM_MATH_CM0_FAMILY */
		132
		133	/* Store the result in the destination buffer in 34.30 format */
		134	*result = sum;
		135
		136	}
		137
		138	/**
		139	* @} end of dot_prod group
		140	*/

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(root)/trunk/Drivers/CMSIS/DSP_Lib/Source/BasicMathFunctions/arm_dot_prod_q15.c – Rev 2