text: /* ----------------------------------------------------------------------    
  * Copyright (C) 2010 ARM Limited. All rights reserved.    
  *    
  * $Date: 14/06/07 1:56a $Revision: 	V1.1.0  
  *    
  * Project: 	    CMSIS DSP Library    
  * Title:		arm_abs_q31.c    
  *    
  * Description:	Q31 vector absolute value.    
  *    
  * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
  *  
  * Version 1.1.0 2012/02/15 
  *    Updated with more optimizations, bug fixes and minor API changes.  
  *   
  * Version 1.0.10 2011/7/15  
  *    Big Endian support added and Merged M0 and M3/M4 Source code.   
  *    
  * Version 1.0.3 2010/11/29   
  *    Re-organized the CMSIS folders and updated documentation.    
  *     
  * Version 1.0.2 2010/11/11    
  *    Documentation updated.     
  *    
  * Version 1.0.1 2010/10/05     
  *    Production release and review comments incorporated.    
  *    
  * Version 1.0.0 2010/09/20     
  *    Production release and review comments incorporated.    
  *    
  * Version 0.0.7  2010/06/10     
  *    Misra-C changes done    
  * -------------------------------------------------------------------- */
  
  #include "arm_math.h"
  
  /**    
   * @ingroup groupMath    
   */
  
  /**    
   * @addtogroup BasicAbs    
   * @{    
   */
  
  
  /**    
   * @brief Q31 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.    
   *    
   * <b>Scaling and Overflow Behavior:</b>    
   * \par    
   * The function uses saturating arithmetic.    
   * The Q31 value -1 (0x80000000) will be saturated to the maximum allowable positive value 0x7FFFFFFF.    
   */
  
  void arm_abs_q31(
    q31_t * pSrc,
    q31_t * pDst,
    uint32_t blockSize)
  {
    uint32_t blkCnt;                               /* loop counter */
    q31_t in;                                      /* Input value */
  
  #ifndef ARM_MATH_CM0
  
    /* Run the below code for Cortex-M4 and Cortex-M3 */
    q31_t in1, in2, in3, in4;
  
    /*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 of input (if -1 then saturated to 0x7fffffff) and then store the results in the destination buffer. */
      in1 = *pSrc++;
      in2 = *pSrc++;
      in3 = *pSrc++;
      in4 = *pSrc++;
  
      *pDst++ = (in1 > 0) ? in1 : __QSUB(0, in1);
      *pDst++ = (in2 > 0) ? in2 : __QSUB(0, in2);
      *pDst++ = (in3 > 0) ? in3 : __QSUB(0, in3);
      *pDst++ = (in4 > 0) ? in4 : __QSUB(0, in4);
  
      /* 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 /*   #ifndef ARM_MATH_CM0   */
  
    while(blkCnt > 0u)
    {
      /* C = |A| */
      /* Calculate absolute value of the input (if -1 then saturated to 0x7fffffff) and then store the results in the destination buffer. */
      in = *pSrc++;
      *pDst++ = (in > 0) ? in : ((in == 0x80000000) ? 0x7fffffff : -in);
  
      /* Decrement the loop counter */
      blkCnt--;
    }
  
  }
  
  /**    
   * @} end of BasicAbs group    
   */
  