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56 mjames 1
/* ----------------------------------------------------------------------
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 * Project:      CMSIS DSP Library
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 * Title:        arm_mat_scale_q15.c
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 * Description:  Multiplies a Q15 matrix by a scalar
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 *
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 * $Date:        27. January 2017
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 * $Revision:    V.1.5.1
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 *
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 * Target Processor: Cortex-M cores
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 * -------------------------------------------------------------------- */
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/*
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 * Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
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 *
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 * SPDX-License-Identifier: Apache-2.0
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 *
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 * Licensed under the Apache License, Version 2.0 (the License); you may
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 * not use this file except in compliance with the License.
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 * You may obtain a copy of the License at
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 *
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 * www.apache.org/licenses/LICENSE-2.0
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 *
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 * Unless required by applicable law or agreed to in writing, software
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 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
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 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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 * See the License for the specific language governing permissions and
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 * limitations under the License.
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 */
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#include "arm_math.h"
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/**
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 * @ingroup groupMatrix
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 */
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/**
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 * @addtogroup MatrixScale
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 * @{
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 */
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/**
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 * @brief Q15 matrix scaling.
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 * @param[in]       *pSrc points to input matrix
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 * @param[in]       scaleFract fractional portion of the scale factor
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 * @param[in]       shift number of bits to shift the result by
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 * @param[out]      *pDst points to output matrix structure
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 * @return              The function returns either
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 * <code>ARM_MATH_SIZE_MISMATCH</code> or <code>ARM_MATH_SUCCESS</code> based on the outcome of size checking.
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 *
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 * @details
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 * <b>Scaling and Overflow Behavior:</b>
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 * \par
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 * The input data <code>*pSrc</code> and <code>scaleFract</code> are in 1.15 format.
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 * These are multiplied to yield a 2.30 intermediate result and this is shifted with saturation to 1.15 format.
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 */
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arm_status arm_mat_scale_q15(
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  const arm_matrix_instance_q15 * pSrc,
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  q15_t scaleFract,
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  int32_t shift,
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  arm_matrix_instance_q15 * pDst)
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{
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  q15_t *pIn = pSrc->pData;                      /* input data matrix pointer */
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  q15_t *pOut = pDst->pData;                     /* output data matrix pointer */
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  uint32_t numSamples;                           /* total number of elements in the matrix */
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  int32_t totShift = 15 - shift;                 /* total shift to apply after scaling */
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  uint32_t blkCnt;                               /* loop counters */
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  arm_status status;                             /* status of matrix scaling     */
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#if defined (ARM_MATH_DSP)
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  q15_t in1, in2, in3, in4;
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  q31_t out1, out2, out3, out4;
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  q31_t inA1, inA2;
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#endif //     #if defined (ARM_MATH_DSP)
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#ifdef ARM_MATH_MATRIX_CHECK
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  /* Check for matrix mismatch */
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  if ((pSrc->numRows != pDst->numRows) || (pSrc->numCols != pDst->numCols))
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  {
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    /* Set status as ARM_MATH_SIZE_MISMATCH */
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    status = ARM_MATH_SIZE_MISMATCH;
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  }
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  else
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#endif //    #ifdef ARM_MATH_MATRIX_CHECK
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  {
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    /* Total number of samples in the input matrix */
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    numSamples = (uint32_t) pSrc->numRows * pSrc->numCols;
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#if defined (ARM_MATH_DSP)
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    /* Run the below code for Cortex-M4 and Cortex-M3 */
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    /* Loop Unrolling */
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    blkCnt = numSamples >> 2;
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    /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
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     ** a second loop below computes the remaining 1 to 3 samples. */
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    while (blkCnt > 0U)
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    {
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      /* C(m,n) = A(m,n) * k */
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      /* Scale, saturate and then store the results in the destination buffer. */
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      /* Reading 2 inputs from memory */
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      inA1 = _SIMD32_OFFSET(pIn);
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      inA2 = _SIMD32_OFFSET(pIn + 2);
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      /* C = A * scale */
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      /* Scale the inputs and then store the 2 results in the destination buffer
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       * in single cycle by packing the outputs */
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      out1 = (q31_t) ((q15_t) (inA1 >> 16) * scaleFract);
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      out2 = (q31_t) ((q15_t) inA1 * scaleFract);
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      out3 = (q31_t) ((q15_t) (inA2 >> 16) * scaleFract);
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      out4 = (q31_t) ((q15_t) inA2 * scaleFract);
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      out1 = out1 >> totShift;
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      inA1 = _SIMD32_OFFSET(pIn + 4);
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      out2 = out2 >> totShift;
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      inA2 = _SIMD32_OFFSET(pIn + 6);
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      out3 = out3 >> totShift;
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      out4 = out4 >> totShift;
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      in1 = (q15_t) (__SSAT(out1, 16));
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      in2 = (q15_t) (__SSAT(out2, 16));
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      in3 = (q15_t) (__SSAT(out3, 16));
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      in4 = (q15_t) (__SSAT(out4, 16));
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      _SIMD32_OFFSET(pOut) = __PKHBT(in2, in1, 16);
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      _SIMD32_OFFSET(pOut + 2) = __PKHBT(in4, in3, 16);
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      /* update pointers to process next sampels */
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      pIn += 4U;
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      pOut += 4U;
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      /* Decrement the numSamples loop counter */
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      blkCnt--;
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    }
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    /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
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     ** No loop unrolling is used. */
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    blkCnt = numSamples % 0x4U;
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#else
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    /* Run the below code for Cortex-M0 */
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    /* Initialize blkCnt with number of samples */
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    blkCnt = numSamples;
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#endif /* #if defined (ARM_MATH_DSP) */
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    while (blkCnt > 0U)
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    {
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      /* C(m,n) = A(m,n) * k */
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      /* Scale, saturate and then store the results in the destination buffer. */
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      *pOut++ =
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        (q15_t) (__SSAT(((q31_t) (*pIn++) * scaleFract) >> totShift, 16));
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      /* Decrement the numSamples loop counter */
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      blkCnt--;
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    }
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    /* Set status as ARM_MATH_SUCCESS */
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    status = ARM_MATH_SUCCESS;
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  }
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  /* Return to application */
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  return (status);
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}
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/**
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 * @} end of MatrixScale group
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 */