lib/main/CMSIS/DSP/Source/BasicMathFunctions/arm_abs_f32.c

   1 /* ----------------------------------------------------------------------
   2  * Project:      CMSIS DSP Library
   3  * Title:        arm_abs_f32.c
   4  * Description:  Floating-point vector absolute value
   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 #include <math.h>
  31
  32 /**
  33  * @ingroup groupMath
  34  */
  35
  36 /**
  37  * @defgroup BasicAbs Vector Absolute Value
  38  *
  39  * Computes the absolute value of a vector on an element-by-element basis.
  40  *
  41  * <pre>
  42  *     pDst[n] = abs(pSrc[n]),   0 <= n < blockSize.
  43  * </pre>
  44  *
  45  * The functions support in-place computation allowing the source and
  46  * destination pointers to reference the same memory buffer.
  47  * There are separate functions for floating-point, Q7, Q15, and Q31 data types.
  48  */
  49
  50 /**
  51  * @addtogroup BasicAbs
  52  * @{
  53  */
  54
  55 /**
  56  * @brief Floating-point vector absolute value.
  57  * @param[in]       *pSrc points to the input buffer
  58  * @param[out]      *pDst points to the output buffer
  59  * @param[in]       blockSize number of samples in each vector
  60  * @return none.
  61  */
  62
  63 void arm_abs_f32(
  64   float32_t * pSrc,
  65   float32_t * pDst,
  66   uint32_t blockSize)
  67 {
  68   uint32_t blkCnt;                               /* loop counter */
  69
  70 #if defined (ARM_MATH_DSP)
  71
  72   /* Run the below code for Cortex-M4 and Cortex-M3 */
  73   float32_t in1, in2, in3, in4;                  /* temporary variables */
  74
  75   /*loop Unrolling */
  76   blkCnt = blockSize >> 2U;
  77
  78   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  79    ** a second loop below computes the remaining 1 to 3 samples. */
  80   while (blkCnt > 0U)
  81   {
  82     /* C = |A| */
  83     /* Calculate absolute and then store the results in the destination buffer. */
  84     /* read sample from source */
  85     in1 = *pSrc;
  86     in2 = *(pSrc + 1);
  87     in3 = *(pSrc + 2);
  88
  89     /* find absolute value */
  90     in1 = fabsf(in1);
  91
  92     /* read sample from source */
  93     in4 = *(pSrc + 3);
  94
  95     /* find absolute value */
  96     in2 = fabsf(in2);
  97
  98     /* read sample from source */
  99     *pDst = in1;
 100
 101     /* find absolute value */
 102     in3 = fabsf(in3);
 103
 104     /* find absolute value */
 105     in4 = fabsf(in4);
 106
 107     /* store result to destination */
 108     *(pDst + 1) = in2;
 109
 110     /* store result to destination */
 111     *(pDst + 2) = in3;
 112
 113     /* store result to destination */
 114     *(pDst + 3) = in4;
 115
 116
 117     /* Update source pointer to process next sampels */
 118     pSrc += 4U;
 119
 120     /* Update destination pointer to process next sampels */
 121     pDst += 4U;
 122
 123     /* Decrement the loop counter */
 124     blkCnt--;
 125   }
 126
 127   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
 128    ** No loop unrolling is used. */
 129   blkCnt = blockSize % 0x4U;
 130
 131 #else
 132
 133   /* Run the below code for Cortex-M0 */
 134
 135   /* Initialize blkCnt with number of samples */
 136   blkCnt = blockSize;
 137
 138 #endif /*   #if defined (ARM_MATH_DSP)   */
 139
 140   while (blkCnt > 0U)
 141   {
 142     /* C = |A| */
 143     /* Calculate absolute and then store the results in the destination buffer. */
 144     *pDst++ = fabsf(*pSrc++);
 145
 146     /* Decrement the loop counter */
 147     blkCnt--;
 148   }
 149 }
 150
 151 /**
 152  * @} end of BasicAbs group
 153  */