pigweed / third_party / github / STMicroelectronics / cmsis_core / cb6d9400754e6c9050487dfa573949b61152ac99 / . / DSP / Source / BasicMathFunctions / arm_abs_f32.c

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

* Project: CMSIS DSP Library | |

* Title: arm_abs_f32.c | |

* Description: Floating-point vector absolute value | |

* | |

* $Date: 27. January 2017 | |

* $Revision: V.1.5.1 | |

* | |

* Target Processor: Cortex-M cores | |

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

/* | |

* Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved. | |

* | |

* SPDX-License-Identifier: Apache-2.0 | |

* | |

* Licensed under the Apache License, Version 2.0 (the License); you may | |

* not use this file except in compliance with the License. | |

* You may obtain a copy of the License at | |

* | |

* www.apache.org/licenses/LICENSE-2.0 | |

* | |

* Unless required by applicable law or agreed to in writing, software | |

* distributed under the License is distributed on an AS IS BASIS, WITHOUT | |

* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |

* See the License for the specific language governing permissions and | |

* limitations under the License. | |

*/ | |

#include "arm_math.h" | |

#include <math.h> | |

/** | |

* @ingroup groupMath | |

*/ | |

/** | |

* @defgroup BasicAbs Vector Absolute Value | |

* | |

* Computes the absolute value of a vector on an element-by-element basis. | |

* | |

* <pre> | |

* pDst[n] = abs(pSrc[n]), 0 <= n < blockSize. | |

* </pre> | |

* | |

* The functions support in-place computation allowing the source and | |

* destination pointers to reference the same memory buffer. | |

* There are separate functions for floating-point, Q7, Q15, and Q31 data types. | |

*/ | |

/** | |

* @addtogroup BasicAbs | |

* @{ | |

*/ | |

/** | |

* @brief Floating-point vector absolute value. | |

* @param[in] *pSrc points to the input buffer | |

* @param[out] *pDst points to the output buffer | |

* @param[in] blockSize number of samples in each vector | |

* @return none. | |

*/ | |

void arm_abs_f32( | |

float32_t * pSrc, | |

float32_t * pDst, | |

uint32_t blockSize) | |

{ | |

uint32_t blkCnt; /* loop counter */ | |

#if defined (ARM_MATH_DSP) | |

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

float32_t in1, in2, in3, in4; /* temporary variables */ | |

/*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| */ | |

/* Calculate absolute and then store the results in the destination buffer. */ | |

/* read sample from source */ | |

in1 = *pSrc; | |

in2 = *(pSrc + 1); | |

in3 = *(pSrc + 2); | |

/* find absolute value */ | |

in1 = fabsf(in1); | |

/* read sample from source */ | |

in4 = *(pSrc + 3); | |

/* find absolute value */ | |

in2 = fabsf(in2); | |

/* read sample from source */ | |

*pDst = in1; | |

/* find absolute value */ | |

in3 = fabsf(in3); | |

/* find absolute value */ | |

in4 = fabsf(in4); | |

/* store result to destination */ | |

*(pDst + 1) = in2; | |

/* store result to destination */ | |

*(pDst + 2) = in3; | |

/* store result to destination */ | |

*(pDst + 3) = in4; | |

/* Update source pointer to process next sampels */ | |

pSrc += 4U; | |

/* Update destination pointer to process next sampels */ | |

pDst += 4U; | |

/* 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 */ | |

/* Initialize blkCnt with number of samples */ | |

blkCnt = blockSize; | |

#endif /* #if defined (ARM_MATH_DSP) */ | |

while (blkCnt > 0U) | |

{ | |

/* C = |A| */ | |

/* Calculate absolute and then store the results in the destination buffer. */ | |

*pDst++ = fabsf(*pSrc++); | |

/* Decrement the loop counter */ | |

blkCnt--; | |

} | |

} | |

/** | |

* @} end of BasicAbs group | |

*/ |