tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/StatisticsFunctions/arm_power_f32.c

   1 /* ----------------------------------------------------------------------
   2 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.
   3 *
   4 * $Date:        17. January 2013
   5 * $Revision:    V1.4.1
   6 *
   7 * Project:          CMSIS DSP Library
   8 * Title:                arm_power_f32.c
   9 *
  10 * Description:  Sum of the squares of the elements of a floating-point vector.
  11 *
  12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
  13 *
  14 * Redistribution and use in source and binary forms, with or without
  15 * modification, are permitted provided that the following conditions
  16 * are met:
  17 *   - Redistributions of source code must retain the above copyright
  18 *     notice, this list of conditions and the following disclaimer.
  19 *   - Redistributions in binary form must reproduce the above copyright
  20 *     notice, this list of conditions and the following disclaimer in
  21 *     the documentation and/or other materials provided with the
  22 *     distribution.
  23 *   - Neither the name of ARM LIMITED nor the names of its contributors
  24 *     may be used to endorse or promote products derived from this
  25 *     software without specific prior written permission.
  26 *
  27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  30 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  31 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  33 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  34 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  35 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  38 * POSSIBILITY OF SUCH DAMAGE.
  39 * ---------------------------------------------------------------------------- */
  40
  41 #include "arm_math.h"
  42
  43 /**
  44  * @ingroup groupStats
  45  */
  46
  47 /**
  48  * @defgroup power Power
  49  *
  50  * Calculates the sum of the squares of the elements in the input vector.
  51  * The underlying algorithm is used:
  52  *
  53  * <pre>
  54  *      Result = pSrc[0] * pSrc[0] + pSrc[1] * pSrc[1] + pSrc[2] * pSrc[2] + ... + pSrc[blockSize-1] * pSrc[blockSize-1];
  55  * </pre>
  56  *
  57  * There are separate functions for floating point, Q31, Q15, and Q7 data types.
  58  */
  59
  60 /**
  61  * @addtogroup power
  62  * @{
  63  */
  64
  65
  66 /**
  67  * @brief Sum of the squares of the elements of a floating-point vector.
  68  * @param[in]       *pSrc points to the input vector
  69  * @param[in]       blockSize length of the input vector
  70  * @param[out]      *pResult sum of the squares value returned here
  71  * @return none.
  72  *
  73  */
  74
  75
  76 void arm_power_f32(
  77   float32_t * pSrc,
  78   uint32_t blockSize,
  79   float32_t * pResult)
  80 {
  81   float32_t sum = 0.0f;                          /* accumulator */
  82   float32_t in;                                  /* Temporary variable to store input value */
  83   uint32_t blkCnt;                               /* loop counter */
  84
  85 #ifndef ARM_MATH_CM0_FAMILY
  86
  87   /* Run the below code for Cortex-M4 and Cortex-M3 */
  88
  89   /*loop Unrolling */
  90   blkCnt = blockSize >> 2u;
  91
  92   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  93    ** a second loop below computes the remaining 1 to 3 samples. */
  94   while(blkCnt > 0u)
  95   {
  96     /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */
  97     /* Compute Power and then store the result in a temporary variable, sum. */
  98     in = *pSrc++;
  99     sum += in * in;
 100     in = *pSrc++;
 101     sum += in * in;
 102     in = *pSrc++;
 103     sum += in * in;
 104     in = *pSrc++;
 105     sum += in * in;
 106
 107     /* Decrement the loop counter */
 108     blkCnt--;
 109   }
 110
 111   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
 112    ** No loop unrolling is used. */
 113   blkCnt = blockSize % 0x4u;
 114
 115
 116 #else
 117
 118   /* Run the below code for Cortex-M0 */
 119
 120   /* Loop over blockSize number of values */
 121   blkCnt = blockSize;
 122
 123 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
 124
 125
 126   while(blkCnt > 0u)
 127   {
 128     /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */
 129     /* compute power and then store the result in a temporary variable, sum. */
 130     in = *pSrc++;
 131     sum += in * in;
 132
 133     /* Decrement the loop counter */
 134     blkCnt--;
 135   }
 136
 137   /* Store the result to the destination */
 138   *pResult = sum;
 139 }
 140
 141 /**
 142  * @} end of power group
 143  */