/* ----------------------------------------------------------------------
* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
*
* $Date: 16/10/14 6:01p $Revision:  V.1.4.5
*
* Project:      CMSIS DSP Library
* Title:        arm_power_f32.c
*
* Description:  Sum of the squares of the elements of a floating-point vector.
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*   - Redistributions of source code must retain the above copyright
*     notice, this list of conditions and the following disclaimer.
*   - Redistributions in binary form must reproduce the above copyright
*     notice, this list of conditions and the following disclaimer in
*     the documentation and/or other materials provided with the
*     distribution.
*   - Neither the name of ARM LIMITED nor the names of its contributors
*     may be used to endorse or promote products derived from this
*     software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* ---------------------------------------------------------------------------- */

#include "arm_math.h"

/**
 * @ingroup groupStats
 */

/**
 * @defgroup power Power
 *
 * Calculates the sum of the squares of the elements in the input vector.
 * The underlying algorithm is used:
 *
 * <pre>
 *  Result = pSrc[0] * pSrc[0] + pSrc[1] * pSrc[1] + pSrc[2] * pSrc[2] + ... + pSrc[blockSize-1] * pSrc[blockSize-1];
 * </pre>
 *
 * There are separate functions for floating point, Q31, Q15, and Q7 data types.
 */

/**
 * @addtogroup power
 * @{
 */


/**
 * @brief Sum of the squares of the elements of a floating-point vector.
 * @param[in]       *pSrc points to the input vector
 * @param[in]       blockSize length of the input vector
 * @param[out]      *pResult sum of the squares value returned here
 * @return none.
 *
 */


void arm_power_f32(
    float32_t * pSrc,
    uint32_t blockSize,
    float32_t * pResult)
{
    float32_t sum = 0.0f;                          /* accumulator */
    float32_t in;                                  /* Temporary variable to store input value */
    uint32_t blkCnt;                               /* loop counter */

#ifndef ARM_MATH_CM0_FAMILY

    /* Run the below code for Cortex-M4 and Cortex-M3 */

    /*loop Unrolling */
    blkCnt = blockSize >> 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)
    {
        /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */
        /* Compute Power and then store the result in a temporary variable, sum. */
        in = *pSrc++;
        sum += in * in;
        in = *pSrc++;
        sum += in * in;
        in = *pSrc++;
        sum += in * in;
        in = *pSrc++;
        sum += in * in;

        /* Decrement the loop counter */
        blkCnt--;
    }

    /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
     ** No loop unrolling is used. */
    blkCnt = blockSize % 0x4u;


#else

    /* Run the below code for Cortex-M0 */

    /* Loop over blockSize number of values */
    blkCnt = blockSize;

#endif /* #ifndef ARM_MATH_CM0_FAMILY */


    while(blkCnt > 0u)
    {
        /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */
        /* compute power and then store the result in a temporary variable, sum. */
        in = *pSrc++;
        sum += in * in;

        /* Decrement the loop counter */
        blkCnt--;
    }

    /* Store the result to the destination */
    *pResult = sum;
}

/**
 * @} end of power group
 */
