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# arm_dot_prod_q31.c

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    00001 /* ----------------------------------------------------------------------
    00002 * Copyright (C) 2010 ARM Limited. All rights reserved.
    00003 *
    00004 * $Date:        29. November 2010
    00005 * $Revision:    V1.0.3
    00006 *
    00007 * Project:      CMSIS DSP Library
    00008 * Title:        arm_dot_prod_q31.c
    00009 *
    00010 * Description:  Q31 dot product.
    00011 *
    00012 * Target Processor: Cortex-M4/Cortex-M3
    00013 *
    00014 * Version 1.0.3 2010/11/29
    00015 *    Re-organized the CMSIS folders and updated documentation.
    00016 *
    00017 * Version 1.0.2 2010/11/11
    00018 *    Documentation updated.
    00019 *
    00020 * Version 1.0.1 2010/10/05
    00021 *    Production release and review comments incorporated.
    00022 *
    00023 * Version 1.0.0 2010/09/20
    00024 *    Production release and review comments incorporated.
    00025 *
    00026 * Version 0.0.7  2010/06/10
    00027 *    Misra-C changes done
    00028 * -------------------------------------------------------------------- */
    00029
    00030 #include "arm_math.h"
    00031
    00059 void arm_dot_prod_q31(
    00060   q31_t * pSrcA,
    00061   q31_t * pSrcB,
    00062   uint32_t blockSize,
    00063   q63_t * result)
    00064 {
    00065   q63_t sum = 0;                                 /* Temporary result storage */
    00066   uint32_t blkCnt;                               /* loop counter */
    00067
    00068
    00069   /*loop Unrolling */
    00070   blkCnt = blockSize >> 2u;
    00071
    00072   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
    00073    ** a second loop below computes the remaining 1 to 3 samples. */
    00074   while(blkCnt > 0u)
    00075   {
    00076     /* C = A[0]* B[0] + A[1]* B[1] + A[2]* B[2] + .....+ A[blockSize-1]* B[blockSize-1] */
    00077     /* Calculate dot product and then store the result in a temporary buffer. */
    00078     sum += ((q63_t) * pSrcA++ * *pSrcB++) >> 14u;
    00079     sum += ((q63_t) * pSrcA++ * *pSrcB++) >> 14u;
    00080     sum += ((q63_t) * pSrcA++ * *pSrcB++) >> 14u;
    00081     sum += ((q63_t) * pSrcA++ * *pSrcB++) >> 14u;
    00082
    00083     /* Decrement the loop counter */
    00084     blkCnt--;
    00085   }
    00086
    00087   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
    00088    ** No loop unrolling is used. */
    00089   blkCnt = blockSize % 0x4u;
    00090
    00091   while(blkCnt > 0u)
    00092   {
    00093     /* C = A[0]* B[0] + A[1]* B[1] + A[2]* B[2] + .....+ A[blockSize-1]* B[blockSize-1] */
    00094     /* Calculate dot product and then store the result in a temporary buffer. */
    00095     sum += ((q63_t) * pSrcA++ * *pSrcB++) >> 14u;
    00096
    00097     /* Decrement the loop counter */
    00098     blkCnt--;
    00099   }
    00100
    00101   /* Store the result in the destination buffer in 16.48 format */
    00102   *result = sum;
    00103 }
    00104

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