lib/main/CMSIS/DSP/Source/StatisticsFunctions/arm_power_f32.c

   1 /* ----------------------------------------------------------------------
   2  * Project:      CMSIS DSP Library
   3  * Title:        arm_power_f32.c
   4  * Description:  Sum of the squares of the elements of a floating-point vector
   5  *
   6  * $Date:        27. January 2017
   7  * $Revision:    V.1.5.1
   8  *
   9  * Target Processor: Cortex-M cores
  10  * -------------------------------------------------------------------- */
  11 /*
  12  * Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
  13  *
  14  * SPDX-License-Identifier: Apache-2.0
  15  *
  16  * Licensed under the Apache License, Version 2.0 (the License); you may
  17  * not use this file except in compliance with the License.
  18  * You may obtain a copy of the License at
  19  *
  20  * www.apache.org/licenses/LICENSE-2.0
  21  *
  22  * Unless required by applicable law or agreed to in writing, software
  23  * distributed under the License is distributed on an AS IS BASIS, WITHOUT
  24  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  25  * See the License for the specific language governing permissions and
  26  * limitations under the License.
  27  */
  28
  29 #include "arm_math.h"
  30
  31 /**
  32  * @ingroup groupStats
  33  */
  34
  35 /**
  36  * @defgroup power Power
  37  *
  38  * Calculates the sum of the squares of the elements in the input vector.
  39  * The underlying algorithm is used:
  40  *
  41  * <pre>
  42  *      Result = pSrc[0] * pSrc[0] + pSrc[1] * pSrc[1] + pSrc[2] * pSrc[2] + ... + pSrc[blockSize-1] * pSrc[blockSize-1];
  43  * </pre>
  44  *
  45  * There are separate functions for floating point, Q31, Q15, and Q7 data types.
  46  */
  47
  48 /**
  49  * @addtogroup power
  50  * @{
  51  */
  52
  53
  54 /**
  55  * @brief Sum of the squares of the elements of a floating-point vector.
  56  * @param[in]       *pSrc points to the input vector
  57  * @param[in]       blockSize length of the input vector
  58  * @param[out]      *pResult sum of the squares value returned here
  59  * @return none.
  60  *
  61  */
  62
  63
  64 void arm_power_f32(
  65   float32_t * pSrc,
  66   uint32_t blockSize,
  67   float32_t * pResult)
  68 {
  69   float32_t sum = 0.0f;                          /* accumulator */
  70   float32_t in;                                  /* Temporary variable to store input value */
  71   uint32_t blkCnt;                               /* loop counter */
  72
  73 #if defined (ARM_MATH_DSP)
  74   /* Run the below code for Cortex-M4 and Cortex-M3 */
  75
  76   /*loop Unrolling */
  77   blkCnt = blockSize >> 2U;
  78
  79   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  80    ** a second loop below computes the remaining 1 to 3 samples. */
  81   while (blkCnt > 0U)
  82   {
  83     /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */
  84     /* Compute Power and then store the result in a temporary variable, sum. */
  85     in = *pSrc++;
  86     sum += in * in;
  87     in = *pSrc++;
  88     sum += in * in;
  89     in = *pSrc++;
  90     sum += in * in;
  91     in = *pSrc++;
  92     sum += in * in;
  93
  94     /* Decrement the loop counter */
  95     blkCnt--;
  96   }
  97
  98   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
  99    ** No loop unrolling is used. */
 100   blkCnt = blockSize % 0x4U;
 101
 102
 103 #else
 104   /* Run the below code for Cortex-M0 */
 105
 106   /* Loop over blockSize number of values */
 107   blkCnt = blockSize;
 108
 109 #endif /* #if defined (ARM_MATH_DSP) */
 110
 111
 112   while (blkCnt > 0U)
 113   {
 114     /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */
 115     /* compute power and then store the result in a temporary variable, sum. */
 116     in = *pSrc++;
 117     sum += in * in;
 118
 119     /* Decrement the loop counter */
 120     blkCnt--;
 121   }
 122
 123   /* Store the result to the destination */
 124   *pResult = sum;
 125 }
 126
 127 /**
 128  * @} end of power group
 129  */