arm_cmplx_dot_prod_q15.c
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CLexer
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r16 | /* ---------------------------------------------------------------------- | ||
* Copyright (C) 2010 ARM Limited. All rights reserved. | ||||
* | ||||
* $Date: 29. November 2010 | ||||
* $Revision: V1.0.3 | ||||
* | ||||
* Project: CMSIS DSP Library | ||||
* Title: arm_cmplx_dot_prod_q15.c | ||||
* | ||||
* Description: Processing function for the Q15 Complex Dot product | ||||
* | ||||
* Target Processor: Cortex-M4/Cortex-M3 | ||||
* | ||||
* Version 1.0.3 2010/11/29 | ||||
* Re-organized the CMSIS folders and updated documentation. | ||||
* | ||||
* Version 1.0.2 2010/11/11 | ||||
* Documentation updated. | ||||
* | ||||
* Version 1.0.1 2010/10/05 | ||||
* Production release and review comments incorporated. | ||||
* | ||||
* Version 1.0.0 2010/09/20 | ||||
* Production release and review comments incorporated. | ||||
* -------------------------------------------------------------------- */ | ||||
#include "arm_math.h" | ||||
/** | ||||
* @ingroup groupCmplxMath | ||||
*/ | ||||
/** | ||||
* @addtogroup cmplx_dot_prod | ||||
* @{ | ||||
*/ | ||||
/** | ||||
* @brief Q15 complex dot product | ||||
* @param *pSrcA points to the first input vector | ||||
* @param *pSrcB points to the second input vector | ||||
* @param numSamples number of complex samples in each vector | ||||
* @param *realResult real part of the result returned here | ||||
* @param *imagResult imaginary part of the result returned here | ||||
* @return none. | ||||
* | ||||
* <b>Scaling and Overflow Behavior:</b> | ||||
* \par | ||||
* The function is implemented using an internal 64-bit accumulator. | ||||
* The intermediate 1.15 by 1.15 multiplications are performed with full precision and yield a 2.30 result. | ||||
* These are accumulated in a 64-bit accumulator with 34.30 precision. | ||||
* As a final step, the accumulators are converted to 8.24 format. | ||||
* The return results <code>realResult</code> and <code>imagResult</code> are in 8.24 format. | ||||
*/ | ||||
void arm_cmplx_dot_prod_q15( | ||||
q15_t * pSrcA, | ||||
q15_t * pSrcB, | ||||
uint32_t numSamples, | ||||
q31_t * realResult, | ||||
q31_t * imagResult) | ||||
{ | ||||
q63_t real_sum = 0, imag_sum = 0; /* Temporary result storage */ | ||||
uint32_t blkCnt; /* loop counter */ | ||||
/*loop Unrolling */ | ||||
blkCnt = numSamples >> 2u; | ||||
/* First part of the processing with loop unrolling. Compute 4 outputs at a time. | ||||
** a second loop below computes the remaining 1 to 3 samples. */ | ||||
while(blkCnt > 0u) | ||||
{ | ||||
/* CReal = A[0]* B[0] + A[2]* B[2] + A[4]* B[4] + .....+ A[numSamples-2]* B[numSamples-2] */ | ||||
real_sum += ((q31_t) * pSrcA++ * *pSrcB++); | ||||
/* CImag = A[1]* B[1] + A[3]* B[3] + A[5]* B[5] + .....+ A[numSamples-1]* B[numSamples-1] */ | ||||
imag_sum += ((q31_t) * pSrcA++ * *pSrcB++); | ||||
real_sum += ((q31_t) * pSrcA++ * *pSrcB++); | ||||
imag_sum += ((q31_t) * pSrcA++ * *pSrcB++); | ||||
real_sum += ((q31_t) * pSrcA++ * *pSrcB++); | ||||
imag_sum += ((q31_t) * pSrcA++ * *pSrcB++); | ||||
real_sum += ((q31_t) * pSrcA++ * *pSrcB++); | ||||
imag_sum += ((q31_t) * pSrcA++ * *pSrcB++); | ||||
/* Decrement the loop counter */ | ||||
blkCnt--; | ||||
} | ||||
/* If the numSamples is not a multiple of 4, compute any remaining output samples here. | ||||
** No loop unrolling is used. */ | ||||
blkCnt = numSamples % 0x4u; | ||||
while(blkCnt > 0u) | ||||
{ | ||||
/* CReal = A[0]* B[0] + A[2]* B[2] + A[4]* B[4] + .....+ A[numSamples-2]* B[numSamples-2] */ | ||||
real_sum += ((q31_t) * pSrcA++ * *pSrcB++); | ||||
/* CImag = A[1]* B[1] + A[3]* B[3] + A[5]* B[5] + .....+ A[numSamples-1]* B[numSamples-1] */ | ||||
imag_sum += ((q31_t) * pSrcA++ * *pSrcB++); | ||||
/* Decrement the loop counter */ | ||||
blkCnt--; | ||||
} | ||||
/* Store the real and imaginary results in 8.24 format */ | ||||
/* Convert real data in 34.30 to 8.24 by 6 right shifts */ | ||||
*realResult = (q31_t) (real_sum) >> 6; | ||||
/* Convert imaginary data in 34.30 to 8.24 by 6 right shifts */ | ||||
*imagResult = (q31_t) (imag_sum) >> 6; | ||||
} | ||||
/** | ||||
* @} end of cmplx_dot_prod group | ||||
*/ | ||||