lib/main/CMSIS/DSP/Source/MatrixFunctions/arm_mat_scale_f32.c

   1 /* ----------------------------------------------------------------------
   2  * Project:      CMSIS DSP Library
   3  * Title:        arm_mat_scale_f32.c
   4  * Description:  Multiplies a floating-point 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  * @defgroup MatrixScale Matrix Scale
  37  *
  38  * Multiplies a matrix by a scalar.  This is accomplished by multiplying each element in the
  39  * matrix by the scalar.  For example:
  40  * \image html MatrixScale.gif "Matrix Scaling of a 3 x 3 matrix"
  41  *
  42  * The function checks to make sure that the input and output matrices are of the same size.
  43  *
  44  * In the fixed-point Q15 and Q31 functions, <code>scale</code> is represented by
  45  * a fractional multiplication <code>scaleFract</code> and an arithmetic shift <code>shift</code>.
  46  * The shift allows the gain of the scaling operation to exceed 1.0.
  47  * The overall scale factor applied to the fixed-point data is
  48  * <pre>
  49  *     scale = scaleFract * 2^shift.
  50  * </pre>
  51  */
  52
  53 /**
  54  * @addtogroup MatrixScale
  55  * @{
  56  */
  57
  58 /**
  59  * @brief Floating-point matrix scaling.
  60  * @param[in]       *pSrc points to input matrix structure
  61  * @param[in]       scale scale factor to be applied
  62  * @param[out]      *pDst points to output matrix structure
  63  * @return              The function returns either <code>ARM_MATH_SIZE_MISMATCH</code>
  64  * or <code>ARM_MATH_SUCCESS</code> based on the outcome of size checking.
  65  *
  66  */
  67
  68 arm_status arm_mat_scale_f32(
  69   const arm_matrix_instance_f32 * pSrc,
  70   float32_t scale,
  71   arm_matrix_instance_f32 * pDst)
  72 {
  73   float32_t *pIn = pSrc->pData;                  /* input data matrix pointer */
  74   float32_t *pOut = pDst->pData;                 /* output data matrix pointer */
  75   uint32_t numSamples;                           /* total number of elements in the matrix */
  76   uint32_t blkCnt;                               /* loop counters */
  77   arm_status status;                             /* status of matrix scaling     */
  78
  79 #if defined (ARM_MATH_DSP)
  80
  81   float32_t in1, in2, in3, in4;                  /* temporary variables */
  82   float32_t out1, out2, out3, out4;              /* temporary variables */
  83
  84 #endif //      #if defined (ARM_MATH_DSP)
  85
  86 #ifdef ARM_MATH_MATRIX_CHECK
  87   /* Check for matrix mismatch condition */
  88   if ((pSrc->numRows != pDst->numRows) || (pSrc->numCols != pDst->numCols))
  89   {
  90     /* Set status as ARM_MATH_SIZE_MISMATCH */
  91     status = ARM_MATH_SIZE_MISMATCH;
  92   }
  93   else
  94 #endif /*    #ifdef ARM_MATH_MATRIX_CHECK    */
  95   {
  96     /* Total number of samples in the input matrix */
  97     numSamples = (uint32_t) pSrc->numRows * pSrc->numCols;
  98
  99 #if defined (ARM_MATH_DSP)
 100
 101     /* Run the below code for Cortex-M4 and Cortex-M3 */
 102
 103     /* Loop Unrolling */
 104     blkCnt = numSamples >> 2;
 105
 106     /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
 107      ** a second loop below computes the remaining 1 to 3 samples. */
 108     while (blkCnt > 0U)
 109     {
 110       /* C(m,n) = A(m,n) * scale */
 111       /* Scaling and results are stored in the destination buffer. */
 112       in1 = pIn[0];
 113       in2 = pIn[1];
 114       in3 = pIn[2];
 115       in4 = pIn[3];
 116
 117       out1 = in1 * scale;
 118       out2 = in2 * scale;
 119       out3 = in3 * scale;
 120       out4 = in4 * scale;
 121
 122
 123       pOut[0] = out1;
 124       pOut[1] = out2;
 125       pOut[2] = out3;
 126       pOut[3] = out4;
 127
 128       /* update pointers to process next sampels */
 129       pIn += 4U;
 130       pOut += 4U;
 131
 132       /* Decrement the numSamples loop counter */
 133       blkCnt--;
 134     }
 135
 136     /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
 137      ** No loop unrolling is used. */
 138     blkCnt = numSamples % 0x4U;
 139
 140 #else
 141
 142     /* Run the below code for Cortex-M0 */
 143
 144     /* Initialize blkCnt with number of samples */
 145     blkCnt = numSamples;
 146
 147 #endif /* #if defined (ARM_MATH_DSP) */
 148
 149     while (blkCnt > 0U)
 150     {
 151       /* C(m,n) = A(m,n) * scale */
 152       /* The results are stored in the destination buffer. */
 153       *pOut++ = (*pIn++) * scale;
 154
 155       /* Decrement the loop counter */
 156       blkCnt--;
 157     }
 158
 159     /* Set status as ARM_MATH_SUCCESS */
 160     status = ARM_MATH_SUCCESS;
 161   }
 162
 163   /* Return to application */
 164   return (status);
 165 }
 166
 167 /**
 168  * @} end of MatrixScale group
 169  */