lib/main/CMSIS/DSP/Source/MatrixFunctions/arm_mat_scale_q31.c

   1 /* ----------------------------------------------------------------------
   2  * Project:      CMSIS DSP Library
   3  * Title:        arm_mat_scale_q31.c
   4  * Description:  Multiplies a Q31 matrix by a scalar
   5  *
   6  * $Date:        27. January 2017
   7  * $Revision:    V.1.5.1
   8  *
   9  * Target Processor: Cortex-M cores
  10  * -------------------------------------------------------------------- */
  11 /*
  12  * Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
  13  *
  14  * SPDX-License-Identifier: Apache-2.0
  15  *
  16  * Licensed under the Apache License, Version 2.0 (the License); you may
  17  * not use this file except in compliance with the License.
  18  * You may obtain a copy of the License at
  19  *
  20  * www.apache.org/licenses/LICENSE-2.0
  21  *
  22  * Unless required by applicable law or agreed to in writing, software
  23  * distributed under the License is distributed on an AS IS BASIS, WITHOUT
  24  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  25  * See the License for the specific language governing permissions and
  26  * limitations under the License.
  27  */
  28
  29 #include "arm_math.h"
  30
  31 /**
  32  * @ingroup groupMatrix
  33  */
  34
  35 /**
  36  * @addtogroup MatrixScale
  37  * @{
  38  */
  39
  40 /**
  41  * @brief Q31 matrix scaling.
  42  * @param[in]       *pSrc points to input matrix
  43  * @param[in]       scaleFract fractional portion of the scale factor
  44  * @param[in]       shift number of bits to shift the result by
  45  * @param[out]      *pDst points to output matrix structure
  46  * @return              The function returns either
  47  * <code>ARM_MATH_SIZE_MISMATCH</code> or <code>ARM_MATH_SUCCESS</code> based on the outcome of size checking.
  48  *
  49  * @details
  50  * <b>Scaling and Overflow Behavior:</b>
  51  * \par
  52  * The input data <code>*pSrc</code> and <code>scaleFract</code> are in 1.31 format.
  53  * These are multiplied to yield a 2.62 intermediate result and this is shifted with saturation to 1.31 format.
  54  */
  55
  56 arm_status arm_mat_scale_q31(
  57   const arm_matrix_instance_q31 * pSrc,
  58   q31_t scaleFract,
  59   int32_t shift,
  60   arm_matrix_instance_q31 * pDst)
  61 {
  62   q31_t *pIn = pSrc->pData;                      /* input data matrix pointer */
  63   q31_t *pOut = pDst->pData;                     /* output data matrix pointer */
  64   uint32_t numSamples;                           /* total number of elements in the matrix */
  65   int32_t totShift = shift + 1;                  /* shift to apply after scaling */
  66   uint32_t blkCnt;                               /* loop counters  */
  67   arm_status status;                             /* status of matrix scaling      */
  68   q31_t in1, in2, out1;                          /* temporary variabels */
  69
  70 #if defined (ARM_MATH_DSP)
  71
  72   q31_t in3, in4, out2, out3, out4;              /* temporary variables */
  73
  74 #endif //      #ifndef ARM_MAT_CM0
  75
  76 #ifdef ARM_MATH_MATRIX_CHECK
  77   /* Check for matrix mismatch  */
  78   if ((pSrc->numRows != pDst->numRows) || (pSrc->numCols != pDst->numCols))
  79   {
  80     /* Set status as ARM_MATH_SIZE_MISMATCH */
  81     status = ARM_MATH_SIZE_MISMATCH;
  82   }
  83   else
  84 #endif //    #ifdef ARM_MATH_MATRIX_CHECK
  85   {
  86     /* Total number of samples in the input matrix */
  87     numSamples = (uint32_t) pSrc->numRows * pSrc->numCols;
  88
  89 #if defined (ARM_MATH_DSP)
  90
  91     /* Run the below code for Cortex-M4 and Cortex-M3 */
  92
  93     /* Loop Unrolling */
  94     blkCnt = numSamples >> 2U;
  95
  96     /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  97      ** a second loop below computes the remaining 1 to 3 samples. */
  98     while (blkCnt > 0U)
  99     {
 100       /* C(m,n) = A(m,n) * k */
 101       /* Read values from input */
 102       in1 = *pIn;
 103       in2 = *(pIn + 1);
 104       in3 = *(pIn + 2);
 105       in4 = *(pIn + 3);
 106
 107       /* multiply input with scaler value */
 108       in1 = ((q63_t) in1 * scaleFract) >> 32;
 109       in2 = ((q63_t) in2 * scaleFract) >> 32;
 110       in3 = ((q63_t) in3 * scaleFract) >> 32;
 111       in4 = ((q63_t) in4 * scaleFract) >> 32;
 112
 113       /* apply shifting */
 114       out1 = in1 << totShift;
 115       out2 = in2 << totShift;
 116
 117       /* saturate the results. */
 118       if (in1 != (out1 >> totShift))
 119         out1 = 0x7FFFFFFF ^ (in1 >> 31);
 120
 121       if (in2 != (out2 >> totShift))
 122         out2 = 0x7FFFFFFF ^ (in2 >> 31);
 123
 124       out3 = in3 << totShift;
 125       out4 = in4 << totShift;
 126
 127       *pOut = out1;
 128       *(pOut + 1) = out2;
 129
 130       if (in3 != (out3 >> totShift))
 131         out3 = 0x7FFFFFFF ^ (in3 >> 31);
 132
 133       if (in4 != (out4 >> totShift))
 134         out4 = 0x7FFFFFFF ^ (in4 >> 31);
 135
 136
 137       *(pOut + 2) = out3;
 138       *(pOut + 3) = out4;
 139
 140       /* update pointers to process next sampels */
 141       pIn += 4U;
 142       pOut += 4U;
 143
 144
 145       /* Decrement the numSamples loop counter */
 146       blkCnt--;
 147     }
 148
 149     /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
 150      ** No loop unrolling is used. */
 151     blkCnt = numSamples % 0x4U;
 152
 153 #else
 154
 155     /* Run the below code for Cortex-M0 */
 156
 157     /* Initialize blkCnt with number of samples */
 158     blkCnt = numSamples;
 159
 160 #endif /* #if defined (ARM_MATH_DSP) */
 161
 162     while (blkCnt > 0U)
 163     {
 164       /* C(m,n) = A(m,n) * k */
 165       /* Scale, saturate and then store the results in the destination buffer. */
 166       in1 = *pIn++;
 167
 168       in2 = ((q63_t) in1 * scaleFract) >> 32;
 169
 170       out1 = in2 << totShift;
 171
 172       if (in2 != (out1 >> totShift))
 173         out1 = 0x7FFFFFFF ^ (in2 >> 31);
 174
 175       *pOut++ = out1;
 176
 177       /* Decrement the numSamples loop counter */
 178       blkCnt--;
 179     }
 180
 181     /* Set status as ARM_MATH_SUCCESS */
 182     status = ARM_MATH_SUCCESS;
 183   }
 184
 185   /* Return to application */
 186   return (status);
 187 }
 188
 189 /**
 190  * @} end of MatrixScale group
 191  */