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src/Cortex-M4-M3/BasicMathFunctions/arm_mult_q15.c@0:1014af42efd9, 2011-03-10 (annotated)

Committer:: simon
Date:: Thu Mar 10 15:07:50 2011 +0000
Revision:: 0:1014af42efd9

Who changed what in which revision?

User	Revision	Line number	New contents of line
simon	0:1014af42efd9	1	/* ----------------------------------------------------------------------
simon	0:1014af42efd9	2	* Copyright (C) 2010 ARM Limited. All rights reserved.
simon	0:1014af42efd9	3	*
simon	0:1014af42efd9	4	* $Date: 29. November 2010
simon	0:1014af42efd9	5	* $Revision: V1.0.3
simon	0:1014af42efd9	6	*
simon	0:1014af42efd9	7	* Project: CMSIS DSP Library
simon	0:1014af42efd9	8	* Title: arm_mult_q15.c
simon	0:1014af42efd9	9	*
simon	0:1014af42efd9	10	* Description: Q15 vector multiplication.
simon	0:1014af42efd9	11	*
simon	0:1014af42efd9	12	* Target Processor: Cortex-M4/Cortex-M3
simon	0:1014af42efd9	13	*
simon	0:1014af42efd9	14	* Version 1.0.3 2010/11/29
simon	0:1014af42efd9	15	* Re-organized the CMSIS folders and updated documentation.
simon	0:1014af42efd9	16	*
simon	0:1014af42efd9	17	* Version 1.0.2 2010/11/11
simon	0:1014af42efd9	18	* Documentation updated.
simon	0:1014af42efd9	19	*
simon	0:1014af42efd9	20	* Version 1.0.1 2010/10/05
simon	0:1014af42efd9	21	* Production release and review comments incorporated.
simon	0:1014af42efd9	22	*
simon	0:1014af42efd9	23	* Version 1.0.0 2010/09/20
simon	0:1014af42efd9	24	* Production release and review comments incorporated.
simon	0:1014af42efd9	25	*
simon	0:1014af42efd9	26	* Version 0.0.5 2010/04/26
simon	0:1014af42efd9	27	* incorporated review comments and updated with latest CMSIS layer
simon	0:1014af42efd9	28	*
simon	0:1014af42efd9	29	* Version 0.0.3 2010/03/10
simon	0:1014af42efd9	30	* Initial version
simon	0:1014af42efd9	31	* -------------------------------------------------------------------- */
simon	0:1014af42efd9	32
simon	0:1014af42efd9	33	#include "arm_math.h"
simon	0:1014af42efd9	34
simon	0:1014af42efd9	35	/**
simon	0:1014af42efd9	36	* @ingroup groupMath
simon	0:1014af42efd9	37	*/
simon	0:1014af42efd9	38
simon	0:1014af42efd9	39	/**
simon	0:1014af42efd9	40	* @addtogroup BasicMult
simon	0:1014af42efd9	41	* @{
simon	0:1014af42efd9	42	*/
simon	0:1014af42efd9	43
simon	0:1014af42efd9	44
simon	0:1014af42efd9	45	/**
simon	0:1014af42efd9	46	* @brief Q15 vector multiplication
simon	0:1014af42efd9	47	* @param[in] *pSrcA points to the first input vector
simon	0:1014af42efd9	48	* @param[in] *pSrcB points to the second input vector
simon	0:1014af42efd9	49	* @param[out] *pDst points to the output vector
simon	0:1014af42efd9	50	* @param[in] blockSize number of samples in each vector
simon	0:1014af42efd9	51	* @return none.
simon	0:1014af42efd9	52	*
simon	0:1014af42efd9	53	* <b>Scaling and Overflow Behavior:</b>
simon	0:1014af42efd9	54	* \par
simon	0:1014af42efd9	55	* The function uses saturating arithmetic.
simon	0:1014af42efd9	56	* Results outside of the allowable Q15 range [0x8000 0x7FFF] will be saturated.
simon	0:1014af42efd9	57	*/
simon	0:1014af42efd9	58
simon	0:1014af42efd9	59	void arm_mult_q15(
simon	0:1014af42efd9	60	q15_t * pSrcA,
simon	0:1014af42efd9	61	q15_t * pSrcB,
simon	0:1014af42efd9	62	q15_t * pDst,
simon	0:1014af42efd9	63	uint32_t blockSize)
simon	0:1014af42efd9	64	{
simon	0:1014af42efd9	65	uint32_t blkCnt; /* loop counters */
simon	0:1014af42efd9	66
simon	0:1014af42efd9	67	/* loop Unrolling */
simon	0:1014af42efd9	68	blkCnt = blockSize >> 2u;
simon	0:1014af42efd9	69
simon	0:1014af42efd9	70	/* First part of the processing with loop unrolling. Compute 4 outputs at a time.
simon	0:1014af42efd9	71	** a second loop below computes the remaining 1 to 3 samples. */
simon	0:1014af42efd9	72	while(blkCnt > 0u)
simon	0:1014af42efd9	73	{
simon	0:1014af42efd9	74	/* C = A * B */
simon	0:1014af42efd9	75	/* Multiply the inputs and store the result in the destination buffer */
simon	0:1014af42efd9	76	pDst++ = (q15_t) __SSAT((((q31_t) (pSrcA++) * (*pSrcB++)) >> 15), 16);
simon	0:1014af42efd9	77	pDst++ = (q15_t) __SSAT((((q31_t) (pSrcA++) * (*pSrcB++)) >> 15), 16);
simon	0:1014af42efd9	78	pDst++ = (q15_t) __SSAT((((q31_t) (pSrcA++) * (*pSrcB++)) >> 15), 16);
simon	0:1014af42efd9	79	pDst++ = (q15_t) __SSAT((((q31_t) (pSrcA++) * (*pSrcB++)) >> 15), 16);
simon	0:1014af42efd9	80
simon	0:1014af42efd9	81	/* Decrement the blockSize loop counter */
simon	0:1014af42efd9	82	blkCnt--;
simon	0:1014af42efd9	83	}
simon	0:1014af42efd9	84
simon	0:1014af42efd9	85	/* If the blockSize is not a multiple of 4, compute any remaining output samples here.
simon	0:1014af42efd9	86	** No loop unrolling is used. */
simon	0:1014af42efd9	87	blkCnt = blockSize % 0x4u;
simon	0:1014af42efd9	88
simon	0:1014af42efd9	89	while(blkCnt > 0u)
simon	0:1014af42efd9	90	{
simon	0:1014af42efd9	91	/* C = A * B */
simon	0:1014af42efd9	92	/* Multiply the inputs and store the result in the destination buffer */
simon	0:1014af42efd9	93	pDst++ = (q15_t) __SSAT((((q31_t) (pSrcA++) * (*pSrcB++)) >> 15), 16);
simon	0:1014af42efd9	94
simon	0:1014af42efd9	95	/* Decrement the blockSize loop counter */
simon	0:1014af42efd9	96	blkCnt--;
simon	0:1014af42efd9	97	}
simon	0:1014af42efd9	98	}
simon	0:1014af42efd9	99
simon	0:1014af42efd9	100	/**
simon	0:1014af42efd9	101	* @} end of BasicMult group
simon	0:1014af42efd9	102	*/

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Type:	Library
Created:	10 Mar 2011
Imports:	907
Forks:	1
Commits:	3
Dependents:	5
Dependencies:	0
Followers:	35

src/Cortex-M4-M3/BasicMathFunctions/arm_mult_q15.c@0:1014af42efd9, 2011-03-10 (annotated)

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