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src/Cortex-M4-M3/ComplexMathFunctions/arm_cmplx_dot_prod_q31.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_cmplx_dot_prod_q31.c
simon	0:1014af42efd9	9	*
simon	0:1014af42efd9	10	* Description: Q31 complex dot product
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
simon	0:1014af42efd9	27	#include "arm_math.h"
simon	0:1014af42efd9	28
simon	0:1014af42efd9	29	/**
simon	0:1014af42efd9	30	* @ingroup groupCmplxMath
simon	0:1014af42efd9	31	*/
simon	0:1014af42efd9	32
simon	0:1014af42efd9	33	/**
simon	0:1014af42efd9	34	* @addtogroup cmplx_dot_prod
simon	0:1014af42efd9	35	* @{
simon	0:1014af42efd9	36	*/
simon	0:1014af42efd9	37
simon	0:1014af42efd9	38	/**
simon	0:1014af42efd9	39	* @brief Q31 complex dot product
simon	0:1014af42efd9	40	* @param *pSrcA points to the first input vector
simon	0:1014af42efd9	41	* @param *pSrcB points to the second input vector
simon	0:1014af42efd9	42	* @param numSamples number of complex samples in each vector
simon	0:1014af42efd9	43	* @param *realResult real part of the result returned here
simon	0:1014af42efd9	44	* @param *imagResult imaginary part of the result returned here
simon	0:1014af42efd9	45	* @return none.
simon	0:1014af42efd9	46	*
simon	0:1014af42efd9	47	* <b>Scaling and Overflow Behavior:</b>
simon	0:1014af42efd9	48	* \par
simon	0:1014af42efd9	49	* The function is implemented using an internal 64-bit accumulator.
simon	0:1014af42efd9	50	* The intermediate 1.31 by 1.31 multiplications are performed with 64-bit precision and then shifted to 16.48 format.
simon	0:1014af42efd9	51	* The internal real and imaginary accumulators are in 16.48 format and provide 15 guard bits.
simon	0:1014af42efd9	52	* Additions are nonsaturating and no overflow will occur as long as <code>numSamples</code> is less than 32768.
simon	0:1014af42efd9	53	* The return results <code>realResult</code> and <code>imagResult</code> are in 16.48 format.
simon	0:1014af42efd9	54	* Input down scaling is not required.
simon	0:1014af42efd9	55	*/
simon	0:1014af42efd9	56
simon	0:1014af42efd9	57	void arm_cmplx_dot_prod_q31(
simon	0:1014af42efd9	58	q31_t * pSrcA,
simon	0:1014af42efd9	59	q31_t * pSrcB,
simon	0:1014af42efd9	60	uint32_t numSamples,
simon	0:1014af42efd9	61	q63_t * realResult,
simon	0:1014af42efd9	62	q63_t * imagResult)
simon	0:1014af42efd9	63	{
simon	0:1014af42efd9	64	q63_t real_sum = 0, imag_sum = 0; /* Temporary result storage */
simon	0:1014af42efd9	65	uint32_t blkCnt; /* loop counter */
simon	0:1014af42efd9	66
simon	0:1014af42efd9	67
simon	0:1014af42efd9	68	/loop Unrolling /
simon	0:1014af42efd9	69	blkCnt = numSamples >> 2u;
simon	0:1014af42efd9	70
simon	0:1014af42efd9	71	/* First part of the processing with loop unrolling. Compute 4 outputs at a time.
simon	0:1014af42efd9	72	** a second loop below computes the remaining 1 to 3 samples. */
simon	0:1014af42efd9	73	while(blkCnt > 0u)
simon	0:1014af42efd9	74	{
simon	0:1014af42efd9	75	/* CReal = A[0]* B[0] + A[2]* B[2] + A[4]* B[4] + .....+ A[numSamples-2]* B[numSamples-2] */
simon	0:1014af42efd9	76	/* Convert real data in 2.62 to 16.48 by 14 right shifts */
simon	0:1014af42efd9	77	real_sum += (q63_t) * pSrcA++ * (*pSrcB++) >> 14;
simon	0:1014af42efd9	78	/* CImag = A[1]* B[1] + A[3]* B[3] + A[5]* B[5] + .....+ A[numSamples-1]* B[numSamples-1] */
simon	0:1014af42efd9	79	/* Convert imag data in 2.62 to 16.48 by 14 right shifts */
simon	0:1014af42efd9	80	imag_sum += (q63_t) * pSrcA++ * (*pSrcB++) >> 14;
simon	0:1014af42efd9	81
simon	0:1014af42efd9	82	real_sum += (q63_t) * pSrcA++ * (*pSrcB++) >> 14;
simon	0:1014af42efd9	83	imag_sum += (q63_t) * pSrcA++ * (*pSrcB++) >> 14;
simon	0:1014af42efd9	84
simon	0:1014af42efd9	85	real_sum += (q63_t) * pSrcA++ * (*pSrcB++) >> 14;
simon	0:1014af42efd9	86	imag_sum += (q63_t) * pSrcA++ * (*pSrcB++) >> 14;
simon	0:1014af42efd9	87
simon	0:1014af42efd9	88	real_sum += (q63_t) * pSrcA++ * (*pSrcB++) >> 14;
simon	0:1014af42efd9	89	imag_sum += (q63_t) * pSrcA++ * (*pSrcB++) >> 14;
simon	0:1014af42efd9	90
simon	0:1014af42efd9	91
simon	0:1014af42efd9	92	/* Decrement the loop counter */
simon	0:1014af42efd9	93	blkCnt--;
simon	0:1014af42efd9	94	}
simon	0:1014af42efd9	95
simon	0:1014af42efd9	96	/* If the numSamples is not a multiple of 4, compute any remaining output samples here.
simon	0:1014af42efd9	97	** No loop unrolling is used. */
simon	0:1014af42efd9	98	blkCnt = numSamples % 0x4u;
simon	0:1014af42efd9	99
simon	0:1014af42efd9	100	while(blkCnt > 0u)
simon	0:1014af42efd9	101	{
simon	0:1014af42efd9	102	/* CReal = A[0]* B[0] + A[2]* B[2] + A[4]* B[4] + .....+ A[numSamples-2]* B[numSamples-2] */
simon	0:1014af42efd9	103	real_sum += (q63_t) * pSrcA++ * (*pSrcB++) >> 14;
simon	0:1014af42efd9	104	/* CImag = A[1]* B[1] + A[3]* B[3] + A[5]* B[5] + .....+ A[numSamples-1]* B[numSamples-1] */
simon	0:1014af42efd9	105	imag_sum += (q63_t) * pSrcA++ * (*pSrcB++) >> 14;
simon	0:1014af42efd9	106
simon	0:1014af42efd9	107	/* Decrement the loop counter */
simon	0:1014af42efd9	108	blkCnt--;
simon	0:1014af42efd9	109	}
simon	0:1014af42efd9	110
simon	0:1014af42efd9	111	/* Store the real and imaginary results in 16.48 format */
simon	0:1014af42efd9	112	*realResult = real_sum;
simon	0:1014af42efd9	113	*imagResult = imag_sum;
simon	0:1014af42efd9	114	}
simon	0:1014af42efd9	115
simon	0:1014af42efd9	116	/**
simon	0:1014af42efd9	117	* @} end of cmplx_dot_prod group
simon	0:1014af42efd9	118	*/

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Type:	Library
Created:	10 Mar 2011
Imports:	907
Forks:	1
Commits:	3
Dependents:	5
Dependencies:	0
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src/Cortex-M4-M3/ComplexMathFunctions/arm_cmplx_dot_prod_q31.c@0:1014af42efd9, 2011-03-10 (annotated)

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