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# arm_mat_scale_q15.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_q15.c
    00009 *
    00010 * Description:  Multiplies a Q15 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_q15(
    00061   const arm_matrix_instance_q15 * pSrc,
    00062   q15_t scaleFract,
    00063   int32_t shift,
    00064   arm_matrix_instance_q15 * pDst)
    00065 {
    00066   q15_t *pIn = pSrc->pData;                      /* input data matrix pointer */
    00067   q15_t *pOut = pDst->pData;                     /* output data matrix pointer */
    00068   uint32_t numSamples;                           /* total number of elements in the matrix */
    00069   int32_t totShift = 15 - shift;                 /* total shift to apply after scaling */
    00070   uint32_t blkCnt;                               /* loop counters */
    00071   arm_status status;                             /* status of matrix scaling     */
    00072
    00073 #ifdef ARM_MATH_MATRIX_CHECK
    00074   /* Check for matrix mismatch */
    00075   if((pSrc->numRows != pDst->numRows) || (pSrc->numCols != pDst->numCols))
    00076   {
    00077     /* Set status as ARM_MATH_SIZE_MISMATCH */
    00078     status = ARM_MATH_SIZE_MISMATCH;
    00079   }
    00080   else
    00081 #endif
    00082   {
    00083     /* Total number of samples in the input matrix */
    00084     numSamples = (uint32_t) pSrc->numRows * pSrc->numCols;
    00085
    00086     /* Loop Unrolling */
    00087     blkCnt = numSamples >> 2;
    00088
    00089     /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
    00090      ** a second loop below computes the remaining 1 to 3 samples. */
    00091     while(blkCnt > 0u)
    00092     {
    00093       /* C(m,n) = A(m,n) * k */
    00094       /* Scale, saturate and then store the results in the destination buffer. */
    00095       *pOut++ =
    00096         (q15_t) (__SSAT(((q31_t) (*pIn++) * scaleFract) >> totShift, 16));
    00097       *pOut++ =
    00098         (q15_t) (__SSAT(((q31_t) (*pIn++) * scaleFract) >> totShift, 16));
    00099       *pOut++ =
    00100         (q15_t) (__SSAT(((q31_t) (*pIn++) * scaleFract) >> totShift, 16));
    00101       *pOut++ =
    00102         (q15_t) (__SSAT(((q31_t) (*pIn++) * scaleFract) >> totShift, 16));
    00103
    00104       /* Decrement the numSamples loop counter */
    00105       blkCnt--;
    00106     }
    00107
    00108     /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
    00109      ** No loop unrolling is used. */
    00110     blkCnt = numSamples % 0x4u;
    00111
    00112     while(blkCnt > 0u)
    00113     {
    00114       /* C(m,n) = A(m,n) * k */
    00115       /* Scale, saturate and then store the results in the destination buffer. */
    00116       *pOut++ =
    00117         (q15_t) (__SSAT(((q31_t) (*pIn++) * scaleFract) >> totShift, 16));
    00118
    00119       /* Decrement the numSamples loop counter */
    00120       blkCnt--;
    00121     }
    00122
    00123     /* Set status as ARM_MATH_SUCCESS */
    00124     status = ARM_MATH_SUCCESS;
    00125   }
    00126
    00127   /* Return to application */
    00128   return (status);
    00129 }
    00130

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