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/* ----------------------------------------------------------------------    

* Copyright (C) 2010-2014 ARM Limited. All rights reserved.    

*    

* $Date:        19. March 2015

* $Revision:    V.1.4.5

*    

* 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

*  

* Redistribution and use in source and binary forms, with or without

* modification, are permitted provided that the following conditions

* are met:

*   - Redistributions of source code must retain the above copyright

*     notice, this list of conditions and the following disclaimer.

*   - Redistributions in binary form must reproduce the above copyright

*     notice, this list of conditions and the following disclaimer in

*     the documentation and/or other materials provided with the

*     distribution.

*   - Neither the name of ARM LIMITED nor the names of its contributors

*     may be used to endorse or promote products derived from this

*     software without specific prior written permission.

*

* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS

* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE

* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,

* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,

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* POSSIBILITY OF SUCH DAMAGE.  

* -------------------------------------------------------------------- */

#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     */

#ifndef ARM_MATH_CM0_FAMILY

  q15_t in1, in2, in3, in4;

  q31_t out1, out2, out3, out4;

  q31_t inA1, inA2;

#endif //     #ifndef ARM_MATH_CM0_FAMILY

#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_FAMILY

    /* 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. */

      /* Reading 2 inputs from memory */

      inA1 = _SIMD32_OFFSET(pIn);

      inA2 = _SIMD32_OFFSET(pIn + 2);

      /* C = A * scale */

      /* Scale the inputs and then store the 2 results in the destination buffer        

       * in single cycle by packing the outputs */

      out1 = (q31_t) ((q15_t) (inA1 >> 16) * scaleFract);

      out2 = (q31_t) ((q15_t) inA1 * scaleFract);

      out3 = (q31_t) ((q15_t) (inA2 >> 16) * scaleFract);

      out4 = (q31_t) ((q15_t) inA2 * scaleFract);

      out1 = out1 >> totShift;

      inA1 = _SIMD32_OFFSET(pIn + 4);

      out2 = out2 >> totShift;

      inA2 = _SIMD32_OFFSET(pIn + 6);

      out3 = out3 >> totShift;

      out4 = out4 >> totShift;

      in1 = (q15_t) (__SSAT(out1, 16));

      in2 = (q15_t) (__SSAT(out2, 16));

      in3 = (q15_t) (__SSAT(out3, 16));

      in4 = (q15_t) (__SSAT(out4, 16));

      _SIMD32_OFFSET(pOut) = __PKHBT(in2, in1, 16);

      _SIMD32_OFFSET(pOut + 2) = __PKHBT(in4, in3, 16);

      /* update pointers to process next sampels */

      pIn += 4u;

      pOut += 4u;

      /* 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_FAMILY */

    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        

 */