lib/main/CMSIS/DSP/Source/MatrixFunctions/arm_mat_sub_q31.c

   1 /* ----------------------------------------------------------------------
   2  * Project:      CMSIS DSP Library
   3  * Title:        arm_mat_sub_q31.c
   4  * Description:  Q31 matrix subtraction
   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 MatrixSub
  37  * @{
  38  */
  39
  40 /**
  41  * @brief Q31 matrix subtraction.
  42  * @param[in]       *pSrcA points to the first input matrix structure
  43  * @param[in]       *pSrcB points to the second input matrix structure
  44  * @param[out]      *pDst points to output matrix structure
  45  * @return              The function returns either
  46  * <code>ARM_MATH_SIZE_MISMATCH</code> or <code>ARM_MATH_SUCCESS</code> based on the outcome of size checking.
  47  *
  48  * <b>Scaling and Overflow Behavior:</b>
  49  * \par
  50  * The function uses saturating arithmetic.
  51  * Results outside of the allowable Q31 range [0x80000000 0x7FFFFFFF] will be saturated.
  52  */
  53
  54
  55 arm_status arm_mat_sub_q31(
  56   const arm_matrix_instance_q31 * pSrcA,
  57   const arm_matrix_instance_q31 * pSrcB,
  58   arm_matrix_instance_q31 * pDst)
  59 {
  60   q31_t *pIn1 = pSrcA->pData;                    /* input data matrix pointer A */
  61   q31_t *pIn2 = pSrcB->pData;                    /* input data matrix pointer B */
  62   q31_t *pOut = pDst->pData;                     /* output data matrix pointer */
  63   q31_t inA1, inB1;                              /* temporary variables */
  64
  65 #if defined (ARM_MATH_DSP)
  66
  67   q31_t inA2, inB2;                              /* temporary variables */
  68   q31_t out1, out2;                              /* temporary variables */
  69
  70 #endif //      #if defined (ARM_MATH_DSP)
  71
  72   uint32_t numSamples;                           /* total number of elements in the matrix  */
  73   uint32_t blkCnt;                               /* loop counters */
  74   arm_status status;                             /* status of matrix subtraction */
  75
  76
  77 #ifdef ARM_MATH_MATRIX_CHECK
  78   /* Check for matrix mismatch condition  */
  79   if ((pSrcA->numRows != pSrcB->numRows) ||
  80      (pSrcA->numCols != pSrcB->numCols) ||
  81      (pSrcA->numRows != pDst->numRows) || (pSrcA->numCols != pDst->numCols))
  82   {
  83     /* Set status as ARM_MATH_SIZE_MISMATCH */
  84     status = ARM_MATH_SIZE_MISMATCH;
  85   }
  86   else
  87 #endif
  88   {
  89     /* Total number of samples in the input matrix */
  90     numSamples = (uint32_t) pSrcA->numRows * pSrcA->numCols;
  91
  92 #if defined (ARM_MATH_DSP)
  93
  94     /* Run the below code for Cortex-M4 and Cortex-M3 */
  95
  96     /* Loop Unrolling */
  97     blkCnt = numSamples >> 2U;
  98
  99     /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
 100      ** a second loop below computes the remaining 1 to 3 samples. */
 101     while (blkCnt > 0U)
 102     {
 103       /* C(m,n) = A(m,n) - B(m,n) */
 104       /* Subtract, saturate and then store the results in the destination buffer. */
 105       /* Read values from source A */
 106       inA1 = pIn1[0];
 107
 108       /* Read values from source B */
 109       inB1 = pIn2[0];
 110
 111       /* Read values from source A */
 112       inA2 = pIn1[1];
 113
 114       /* Subtract and saturate */
 115       out1 = __QSUB(inA1, inB1);
 116
 117       /* Read values from source B */
 118       inB2 = pIn2[1];
 119
 120       /* Read values from source A */
 121       inA1 = pIn1[2];
 122
 123       /* Subtract and saturate */
 124       out2 = __QSUB(inA2, inB2);
 125
 126       /* Read values from source B */
 127       inB1 = pIn2[2];
 128
 129       /* Store result in destination */
 130       pOut[0] = out1;
 131       pOut[1] = out2;
 132
 133       /* Read values from source A */
 134       inA2 = pIn1[3];
 135
 136       /* Read values from source B */
 137       inB2 = pIn2[3];
 138
 139       /* Subtract and saturate */
 140       out1 = __QSUB(inA1, inB1);
 141
 142       /* Subtract and saturate */
 143       out2 = __QSUB(inA2, inB2);
 144
 145       /* Store result in destination */
 146       pOut[2] = out1;
 147       pOut[3] = out2;
 148
 149       /* update pointers to process next samples */
 150       pIn1 += 4U;
 151       pIn2 += 4U;
 152       pOut += 4U;
 153
 154       /* Decrement the loop counter */
 155       blkCnt--;
 156     }
 157
 158     /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
 159      ** No loop unrolling is used. */
 160     blkCnt = numSamples % 0x4U;
 161
 162 #else
 163
 164     /* Run the below code for Cortex-M0 */
 165
 166     /* Initialize blkCnt with number of samples */
 167     blkCnt = numSamples;
 168
 169 #endif /* #if defined (ARM_MATH_DSP) */
 170
 171     while (blkCnt > 0U)
 172     {
 173       /* C(m,n) = A(m,n) - B(m,n) */
 174       /* Subtract, saturate and then store the results in the destination buffer. */
 175       inA1 = *pIn1++;
 176       inB1 = *pIn2++;
 177
 178       inA1 = __QSUB(inA1, inB1);
 179
 180       *pOut++ = inA1;
 181
 182       /* Decrement the loop counter */
 183       blkCnt--;
 184     }
 185
 186     /* Set status as ARM_MATH_SUCCESS */
 187     status = ARM_MATH_SUCCESS;
 188   }
 189
 190   /* Return to application */
 191   return (status);
 192 }
 193
 194 /**
 195  * @} end of MatrixSub group
 196  */