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  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.  */
  154.