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  1. /* ----------------------------------------------------------------------    
  2. * Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
  3. *    
  4. * $Date:        19. March 2015
  5. * $Revision:    V.1.4.5
  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.  */
  166.