tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/BasicMathFunctions/arm_abs_f32.c

   1 /* ----------------------------------------------------------------------
   2 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.
   3 *
   4 * $Date:        17. January 2013
   5 * $Revision:    V1.4.1
   6 *
   7 * Project:          CMSIS DSP Library
   8 * Title:                arm_abs_f32.c
   9 *
  10 * Description:  Vector absolute value.
  11 *
  12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
  13 *
  14 * Redistribution and use in source and binary forms, with or without
  15 * modification, are permitted provided that the following conditions
  16 * are met:
  17 *   - Redistributions of source code must retain the above copyright
  18 *     notice, this list of conditions and the following disclaimer.
  19 *   - Redistributions in binary form must reproduce the above copyright
  20 *     notice, this list of conditions and the following disclaimer in
  21 *     the documentation and/or other materials provided with the
  22 *     distribution.
  23 *   - Neither the name of ARM LIMITED nor the names of its contributors
  24 *     may be used to endorse or promote products derived from this
  25 *     software without specific prior written permission.
  26 *
  27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  30 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  31 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  33 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  34 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  35 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  38 * POSSIBILITY OF SUCH DAMAGE.
  39 * ---------------------------------------------------------------------------- */
  40
  41 #include "arm_math.h"
  42 #include <math.h>
  43
  44 /**
  45  * @ingroup groupMath
  46  */
  47
  48 /**
  49  * @defgroup BasicAbs Vector Absolute Value
  50  *
  51  * Computes the absolute value of a vector on an element-by-element basis.
  52  *
  53  * <pre>
  54  *     pDst[n] = abs(pSrc[n]),   0 <= n < blockSize.
  55  * </pre>
  56  *
  57  * The functions support in-place computation allowing the source and
  58  * destination pointers to reference the same memory buffer.
  59  * There are separate functions for floating-point, Q7, Q15, and Q31 data types.
  60  */
  61
  62 /**
  63  * @addtogroup BasicAbs
  64  * @{
  65  */
  66
  67 /**
  68  * @brief Floating-point vector absolute value.
  69  * @param[in]       *pSrc points to the input buffer
  70  * @param[out]      *pDst points to the output buffer
  71  * @param[in]       blockSize number of samples in each vector
  72  * @return none.
  73  */
  74
  75 void arm_abs_f32(
  76   float32_t * pSrc,
  77   float32_t * pDst,
  78   uint32_t blockSize)
  79 {
  80   uint32_t blkCnt;                               /* loop counter */
  81
  82 #ifndef ARM_MATH_CM0_FAMILY
  83
  84   /* Run the below code for Cortex-M4 and Cortex-M3 */
  85   float32_t in1, in2, in3, in4;                  /* temporary variables */
  86
  87   /*loop Unrolling */
  88   blkCnt = blockSize >> 2u;
  89
  90   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  91    ** a second loop below computes the remaining 1 to 3 samples. */
  92   while(blkCnt > 0u)
  93   {
  94     /* C = |A| */
  95     /* Calculate absolute and then store the results in the destination buffer. */
  96     /* read sample from source */
  97     in1 = *pSrc;
  98     in2 = *(pSrc + 1);
  99     in3 = *(pSrc + 2);
 100
 101     /* find absolute value */
 102     in1 = fabsf(in1);
 103
 104     /* read sample from source */
 105     in4 = *(pSrc + 3);
 106
 107     /* find absolute value */
 108     in2 = fabsf(in2);
 109
 110     /* read sample from source */
 111     *pDst = in1;
 112
 113     /* find absolute value */
 114     in3 = fabsf(in3);
 115
 116     /* find absolute value */
 117     in4 = fabsf(in4);
 118
 119     /* store result to destination */
 120     *(pDst + 1) = in2;
 121
 122     /* store result to destination */
 123     *(pDst + 2) = in3;
 124
 125     /* store result to destination */
 126     *(pDst + 3) = in4;
 127
 128
 129     /* Update source pointer to process next sampels */
 130     pSrc += 4u;
 131
 132     /* Update destination pointer to process next sampels */
 133     pDst += 4u;
 134
 135     /* Decrement the loop counter */
 136     blkCnt--;
 137   }
 138
 139   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
 140    ** No loop unrolling is used. */
 141   blkCnt = blockSize % 0x4u;
 142
 143 #else
 144
 145   /* Run the below code for Cortex-M0 */
 146
 147   /* Initialize blkCnt with number of samples */
 148   blkCnt = blockSize;
 149
 150 #endif /*   #ifndef ARM_MATH_CM0_FAMILY   */
 151
 152   while(blkCnt > 0u)
 153   {
 154     /* C = |A| */
 155     /* Calculate absolute and then store the results in the destination buffer. */
 156     *pDst++ = fabsf(*pSrc++);
 157
 158     /* Decrement the loop counter */
 159     blkCnt--;
 160   }
 161 }
 162
 163 /**
 164  * @} end of BasicAbs group
 165  */