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# arm_mat_scale_q31.c

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    00001 /* ----------------------------------------------------------------------
    00002 * Copyright (C) 2010 ARM Limited. All rights reserved.
    00003 *
    00004 * $Date:        29. November 2010
    00005 * $Revision:    V1.0.3
    00006 *
    00007 * Project:      CMSIS DSP Library
    00008 * Title:        arm_mat_scale_q31.c
    00009 *
    00010 * Description:  Multiplies a Q31 matrix by a scalar.
    00011 *
    00012 * Target Processor: Cortex-M4/Cortex-M3
    00013 *
    00014 * Version 1.0.3 2010/11/29
    00015 *    Re-organized the CMSIS folders and updated documentation.
    00016 *
    00017 * Version 1.0.2 2010/11/11
    00018 *    Documentation updated.
    00019 *
    00020 * Version 1.0.1 2010/10/05
    00021 *    Production release and review comments incorporated.
    00022 *
    00023 * Version 1.0.0 2010/09/20
    00024 *    Production release and review comments incorporated.
    00025 *
    00026 * Version 0.0.5  2010/04/26
    00027 *    incorporated review comments and updated with latest CMSIS layer
    00028 *
    00029 * Version 0.0.3  2010/03/10
    00030 *    Initial version
    00031 * -------------------------------------------------------------------- */
    00032
    00033 #include "arm_math.h"
    00034
    00060 arm_status arm_mat_scale_q31(
    00061   const arm_matrix_instance_q31 * pSrc,
    00062   q31_t scaleFract,
    00063   int32_t shift,
    00064   arm_matrix_instance_q31 * pDst)
    00065 {
    00066   q31_t *pIn = pSrc->pData;                      /* input data matrix pointer */
    00067   q31_t *pOut = pDst->pData;                     /* output data matrix pointer */
    00068   q63_t out;                                     /* temporary variable to hold output value */
    00069   uint32_t numSamples;                           /* total number of elements in the matrix */
    00070   int32_t totShift = 31 - shift;                 /* shift to apply after scaling */
    00071   uint32_t blkCnt;                               /* loop counters  */
    00072   arm_status status;                             /* status of matrix scaling      */
    00073
    00074 #ifdef ARM_MATH_MATRIX_CHECK
    00075   /* Check for matrix mismatch  */
    00076   if((pSrc->numRows != pDst->numRows) || (pSrc->numCols != pDst->numCols))
    00077   {
    00078     /* Set status as ARM_MATH_SIZE_MISMATCH */
    00079     status = ARM_MATH_SIZE_MISMATCH;
    00080   }
    00081   else
    00082 #endif
    00083   {
    00084     /* Total number of samples in the input matrix */
    00085     numSamples = (uint32_t) pSrc->numRows * pSrc->numCols;
    00086
    00087     /* Loop Unrolling */
    00088     blkCnt = numSamples >> 2u;
    00089
    00090     /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
    00091      ** a second loop below computes the remaining 1 to 3 samples. */
    00092     while(blkCnt > 0u)
    00093     {
    00094       /* C(m,n) = A(m,n) * k */
    00095       /* Scale, saturate and then store the results in the destination buffer. */
    00096       out = ((q63_t) * pIn++ * scaleFract) >> totShift;
    00097       *pOut++ = clip_q63_to_q31(out);
    00098       out = ((q63_t) * pIn++ * scaleFract) >> totShift;
    00099       *pOut++ = clip_q63_to_q31(out);
    00100       out = ((q63_t) * pIn++ * scaleFract) >> totShift;
    00101       *pOut++ = clip_q63_to_q31(out);
    00102       out = ((q63_t) * pIn++ * scaleFract) >> totShift;
    00103       *pOut++ = clip_q63_to_q31(out);
    00104
    00105       /* Decrement the numSamples loop counter */
    00106       blkCnt--;
    00107     }
    00108
    00109     /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
    00110      ** No loop unrolling is used. */
    00111     blkCnt = numSamples % 0x4u;
    00112
    00113     while(blkCnt > 0u)
    00114     {
    00115       /* C(m,n) = A(m,n) * k */
    00116       /* Scale, saturate and then store the results in the destination buffer. */
    00117       out = ((q63_t) * pIn++ * scaleFract) >> totShift;
    00118       *pOut++ = clip_q63_to_q31(out);
    00119
    00120       /* Decrement the numSamples loop counter */
    00121       blkCnt--;
    00122     }
    00123
    00124     /* Set status as ARM_MATH_SUCCESS */
    00125     status = ARM_MATH_SUCCESS;
    00126   }
    00127
    00128   /* Return to application */
    00129   return (status);
    00130 }
    00131

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