pigweed / third_party / github / STMicroelectronics / cmsis_core / 7dd288b23bf605a3a2fafa81a29d2c96a2fd83ce / . / DSP_Lib / Source / StatisticsFunctions / arm_power_f32.c

/* ---------------------------------------------------------------------- | |

* Copyright (C) 2010-2014 ARM Limited. All rights reserved. | |

* | |

* $Date: 19. March 2015 | |

* $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, | |

* 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 | |

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* 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: | |

* | |

* <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 | |

*/ |