hardware/arduino/sam/system/CMSIS/CMSIS/DSP_Lib/Source/MatrixFunctions/arm_mat_scale_q15.c

/* ----------------------------------------------------------------------   
* Copyright (C) 2010 ARM Limited. All rights reserved.   
*   
* $Date:        15. July 2011  
* $Revision: 	V1.0.10  
*   
* Project: 	    CMSIS DSP Library   
* Title:	    arm_mat_scale_q15.c   
*   
* Description:	Multiplies a Q15 matrix by a scalar.   
*   
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*  
* 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 0.0.5  2010/04/26    
*    incorporated review comments and updated with latest CMSIS layer   
*   
* Version 0.0.3  2010/03/10    
*    Initial version   
* -------------------------------------------------------------------- */

#include "arm_math.h"

/**   
 * @ingroup groupMatrix   
 */

/**   
 * @addtogroup MatrixScale   
 * @{   
 */

/**   
 * @brief Q15 matrix scaling.   
 * @param[in]       *pSrc points to input matrix   
 * @param[in]       scaleFract fractional portion of the scale factor   
 * @param[in]       shift number of bits to shift the result by   
 * @param[out]      *pDst points to output matrix structure   
 * @return     		The function returns either   
 * <code>ARM_MATH_SIZE_MISMATCH</code> or <code>ARM_MATH_SUCCESS</code> based on the outcome of size checking.   
 *   
 * @details   
 * <b>Scaling and Overflow Behavior:</b>   
 * \par   
 * The input data <code>*pSrc</code> and <code>scaleFract</code> are in 1.15 format.   
 * These are multiplied to yield a 2.30 intermediate result and this is shifted with saturation to 1.15 format.   
 */

arm_status arm_mat_scale_q15(
  const arm_matrix_instance_q15 * pSrc,
  q15_t scaleFract,
  int32_t shift,
  arm_matrix_instance_q15 * pDst)
{
  q15_t *pIn = pSrc->pData;                      /* input data matrix pointer */
  q15_t *pOut = pDst->pData;                     /* output data matrix pointer */
  uint32_t numSamples;                           /* total number of elements in the matrix */
  int32_t totShift = 15 - shift;                 /* total shift to apply after scaling */
  uint32_t blkCnt;                               /* loop counters */
  arm_status status;                             /* status of matrix scaling     */

#ifdef ARM_MATH_MATRIX_CHECK


  /* Check for matrix mismatch */
  if((pSrc->numRows != pDst->numRows) || (pSrc->numCols != pDst->numCols))
  {
    /* Set status as ARM_MATH_SIZE_MISMATCH */
    status = ARM_MATH_SIZE_MISMATCH;
  }
  else
#endif /*    #ifdef ARM_MATH_MATRIX_CHECK    */

  {
    /* Total number of samples in the input matrix */
    numSamples = (uint32_t) pSrc->numRows * pSrc->numCols;

#ifndef ARM_MATH_CM0

    /* Run the below code for Cortex-M4 and Cortex-M3 */
    /* Loop Unrolling */
    blkCnt = numSamples >> 2;

    /* 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(m,n) = A(m,n) * k */
      /* Scale, saturate and then store the results in the destination buffer. */
      *pOut++ =
        (q15_t) (__SSAT(((q31_t) (*pIn++) * scaleFract) >> totShift, 16));
      *pOut++ =
        (q15_t) (__SSAT(((q31_t) (*pIn++) * scaleFract) >> totShift, 16));
      *pOut++ =
        (q15_t) (__SSAT(((q31_t) (*pIn++) * scaleFract) >> totShift, 16));
      *pOut++ =
        (q15_t) (__SSAT(((q31_t) (*pIn++) * scaleFract) >> totShift, 16));

      /* Decrement the numSamples loop counter */
      blkCnt--;
    }

    /* If the numSamples is not a multiple of 4, compute any remaining output samples here.   
     ** No loop unrolling is used. */
    blkCnt = numSamples % 0x4u;

#else

    /* Run the below code for Cortex-M0 */

    /* Initialize blkCnt with number of samples */
    blkCnt = numSamples;

#endif /* #ifndef ARM_MATH_CM0 */

    while(blkCnt > 0u)
    {
      /* C(m,n) = A(m,n) * k */
      /* Scale, saturate and then store the results in the destination buffer. */
      *pOut++ =
        (q15_t) (__SSAT(((q31_t) (*pIn++) * scaleFract) >> totShift, 16));

      /* Decrement the numSamples loop counter */
      blkCnt--;
    }
    /* Set status as ARM_MATH_SUCCESS */
    status = ARM_MATH_SUCCESS;
  }

  /* Return to application */
  return (status);
}

/**   
 * @} end of MatrixScale group   
 */