/* ---------------------------------------------------------------------- * Copyright (C) 2010-2013 ARM Limited. All rights reserved. * * $Date: 17. January 2013 * $Revision: V1.4.1 * * 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, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ---------------------------------------------------------------------------- */ #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: * *
    
 * 	Result = pSrc[0] * pSrc[0] + pSrc[1] * pSrc[1] + pSrc[2] * pSrc[2] + ... + pSrc[blockSize-1] * pSrc[blockSize-1];    
 * 
* * 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 */