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# arm_cmplx_dot_prod_q15.c

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    00001 /* ----------------------------------------------------------------------
    00002 * Copyright (C) 2010 ARM Limited. All rights reserved.
    00003 *
    00004 * $Date:        15. July 2011
    00005 * $Revision:    V1.0.10
    00006 *
    00007 * Project:      CMSIS DSP Library
    00008 * Title:        arm_cmplx_dot_prod_q15.c
    00009 *
    00010 * Description:  Processing function for the Q15 Complex Dot product
    00011 *
    00012 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
    00013 *
    00014 * Version 1.0.10 2011/7/15
    00015 *    Big Endian support added and Merged M0 and M3/M4 Source code.
    00016 *
    00017 * Version 1.0.3 2010/11/29
    00018 *    Re-organized the CMSIS folders and updated documentation.
    00019 *
    00020 * Version 1.0.2 2010/11/11
    00021 *    Documentation updated.
    00022 *
    00023 * Version 1.0.1 2010/10/05
    00024 *    Production release and review comments incorporated.
    00025 *
    00026 * Version 1.0.0 2010/09/20
    00027 *    Production release and review comments incorporated.
    00028 * -------------------------------------------------------------------- */
    00029
    00030 #include "arm_math.h"
    00031
    00059 void arm_cmplx_dot_prod_q15(
    00060   q15_t * pSrcA,
    00061   q15_t * pSrcB,
    00062   uint32_t numSamples,
    00063   q31_t * realResult,
    00064   q31_t * imagResult)
    00065 {
    00066   q63_t real_sum = 0, imag_sum = 0;              /* Temporary result storage */
    00067
    00068 #ifndef ARM_MATH_CM0
    00069
    00070   /* Run the below code for Cortex-M4 and Cortex-M3 */
    00071   uint32_t blkCnt;                               /* loop counter */
    00072
    00073
    00074   /*loop Unrolling */
    00075   blkCnt = numSamples >> 2u;
    00076
    00077   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
    00078    ** a second loop below computes the remaining 1 to 3 samples. */
    00079   while(blkCnt > 0u)
    00080   {
    00081     /* CReal = A[0]* B[0] + A[2]* B[2] + A[4]* B[4] + .....+ A[numSamples-2]* B[numSamples-2] */
    00082     real_sum += ((q31_t) * pSrcA++ * *pSrcB++);
    00083
    00084     /* CImag = A[1]* B[1] + A[3]* B[3] + A[5]* B[5] + .....+ A[numSamples-1]* B[numSamples-1] */
    00085     imag_sum += ((q31_t) * pSrcA++ * *pSrcB++);
    00086
    00087     real_sum += ((q31_t) * pSrcA++ * *pSrcB++);
    00088     imag_sum += ((q31_t) * pSrcA++ * *pSrcB++);
    00089
    00090     real_sum += ((q31_t) * pSrcA++ * *pSrcB++);
    00091     imag_sum += ((q31_t) * pSrcA++ * *pSrcB++);
    00092
    00093     real_sum += ((q31_t) * pSrcA++ * *pSrcB++);
    00094     imag_sum += ((q31_t) * pSrcA++ * *pSrcB++);
    00095
    00096     /* Decrement the loop counter */
    00097     blkCnt--;
    00098   }
    00099
    00100   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
    00101    ** No loop unrolling is used. */
    00102   blkCnt = numSamples % 0x4u;
    00103
    00104   while(blkCnt > 0u)
    00105   {
    00106     /* CReal = A[0]* B[0] + A[2]* B[2] + A[4]* B[4] + .....+ A[numSamples-2]* B[numSamples-2] */
    00107     real_sum += ((q31_t) * pSrcA++ * *pSrcB++);
    00108     /* CImag = A[1]* B[1] + A[3]* B[3] + A[5]* B[5] + .....+ A[numSamples-1]* B[numSamples-1] */
    00109     imag_sum += ((q31_t) * pSrcA++ * *pSrcB++);
    00110
    00111     /* Decrement the loop counter */
    00112     blkCnt--;
    00113   }
    00114
    00115 #else
    00116
    00117   /* Run the below code for Cortex-M0 */
    00118
    00119   while(numSamples > 0u)
    00120   {
    00121     /* CReal = A[0]* B[0] + A[2]* B[2] + A[4]* B[4] + .....+ A[numSamples-2]* B[numSamples-2] */
    00122     real_sum += ((q31_t) * pSrcA++ * *pSrcB++);
    00123     /* CImag = A[1]* B[1] + A[3]* B[3] + A[5]* B[5] + .....+ A[numSamples-1]* B[numSamples-1] */
    00124     imag_sum += ((q31_t) * pSrcA++ * *pSrcB++);
    00125
    00126     /* Decrement the loop counter */
    00127     numSamples--;
    00128   }
    00129
    00130 #endif /* #ifndef ARM_MATH_CM0 */
    00131
    00132   /* Store the real and imaginary results in 8.24 format  */
    00133   /* Convert real data in 34.30 to 8.24 by 6 right shifts */
    00134   *realResult = (q31_t) (real_sum) >> 6;
    00135   /* Convert imaginary data in 34.30 to 8.24 by 6 right shifts */
    00136   *imagResult = (q31_t) (imag_sum) >> 6;
    00137 }
    00138

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