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# arm_power_q7.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_power_q7.c
    00009 *
    00010 * Description:  Sum of the squares of the elements of a Q7 vector.
    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
    00062 void arm_power_q7(
    00063   q7_t * pSrc,
    00064   uint32_t blockSize,
    00065   q31_t * pResult)
    00066 {
    00067   q31_t sum = 0;                                 /* Temporary result storage */
    00068   q7_t in;                                       /* Temporary variable to store input */
    00069   uint32_t blkCnt;                               /* loop counter */
    00070
    00071 #ifndef ARM_MATH_CM0
    00072
    00073   /* Run the below code for Cortex-M4 and Cortex-M3 */
    00074
    00075   q31_t input1;                                  /* Temporary variable to store packed input */
    00076   q15_t in1, in2;                                /* Temporary variables to store input */
    00077
    00078   /*loop Unrolling */
    00079   blkCnt = blockSize >> 2u;
    00080
    00081   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
    00082    ** a second loop below computes the remaining 1 to 3 samples. */
    00083   while(blkCnt > 0u)
    00084   {
    00085     /* Reading two inputs of pSrc vector and packing */
    00086     in1 = (q15_t) * pSrc++;
    00087     in2 = (q15_t) * pSrc++;
    00088     input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);
    00089
    00090     /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */
    00091     /* Compute Power and then store the result in a temporary variable, sum. */
    00092     sum = __SMLAD(input1, input1, sum);
    00093
    00094     /* Reading two inputs of pSrc vector and packing */
    00095     in1 = (q15_t) * pSrc++;
    00096     in2 = (q15_t) * pSrc++;
    00097     input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16);
    00098
    00099     /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */
    00100     /* Compute Power and then store the result in a temporary variable, sum. */
    00101     sum = __SMLAD(input1, input1, sum);
    00102
    00103     /* Decrement the loop counter */
    00104     blkCnt--;
    00105   }
    00106
    00107   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
    00108    ** No loop unrolling is used. */
    00109   blkCnt = blockSize % 0x4u;
    00110
    00111 #else
    00112
    00113   /* Run the below code for Cortex-M0 */
    00114
    00115   /* Loop over blockSize number of values */
    00116   blkCnt = blockSize;
    00117
    00118 #endif /* #ifndef ARM_MATH_CM0 */
    00119
    00120   while(blkCnt > 0u)
    00121   {
    00122     /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */
    00123     /* Compute Power and then store the result in a temporary variable, sum. */
    00124     in = *pSrc++;
    00125     sum += ((q15_t) in * in);
    00126
    00127     /* Decrement the loop counter */
    00128     blkCnt--;
    00129   }
    00130
    00131   /* Store the result in 18.14 format  */
    00132   *pResult = sum;
    00133 }
    00134

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