summaryrefslogtreecommitdiff
path: root/DSP/Source/MatrixFunctions/arm_mat_sub_q15.c
blob: 5d5e5d0fa2cea3cc0c1321cc70390667e8ddadbc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
/* ----------------------------------------------------------------------
 * Project:      CMSIS DSP Library
 * Title:        arm_mat_sub_q15.c
 * Description:  Q15 Matrix subtraction
 *
 * $Date:        18. March 2019
 * $Revision:    V1.6.0
 *
 * Target Processor: Cortex-M cores
 * -------------------------------------------------------------------- */
/*
 * Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved.
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Licensed under the Apache License, Version 2.0 (the License); you may
 * not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "arm_math.h"

/**
  @ingroup groupMatrix
 */

/**
  @addtogroup MatrixSub
  @{
 */

/**
  @brief         Q15 matrix subtraction.
  @param[in]     pSrcA      points to the first input matrix structure
  @param[in]     pSrcB      points to the second input matrix structure
  @param[out]    pDst       points to output matrix structure
  @return        execution status
                   - \ref ARM_MATH_SUCCESS       : Operation successful
                   - \ref ARM_MATH_SIZE_MISMATCH : Matrix size check failed

  @par           Scaling and Overflow Behavior
                   The function uses saturating arithmetic.
                   Results outside of the allowable Q15 range [0x8000 0x7FFF] are saturated.
 */

arm_status arm_mat_sub_q15(
  const arm_matrix_instance_q15 * pSrcA,
  const arm_matrix_instance_q15 * pSrcB,
        arm_matrix_instance_q15 * pDst)
{
        q15_t *pInA = pSrcA->pData;                    /* input data matrix pointer A */
        q15_t *pInB = pSrcB->pData;                    /* input data matrix pointer B */
        q15_t *pOut = pDst->pData;                     /* output data matrix pointer */

        uint32_t numSamples;                           /* total number of elements in the matrix */
        uint32_t blkCnt;                               /* loop counters  */
        arm_status status;                             /* status of matrix subtraction  */

#ifdef ARM_MATH_MATRIX_CHECK

  /* Check for matrix mismatch condition */
  if ((pSrcA->numRows != pSrcB->numRows) ||
      (pSrcA->numCols != pSrcB->numCols) ||
      (pSrcA->numRows != pDst->numRows)  ||
      (pSrcA->numCols != pDst->numCols)    )
  {
    /* Set status as ARM_MATH_SIZE_MISMATCH */
    status = ARM_MATH_SIZE_MISMATCH;
  }
  else
#endif /* #ifdef ARM_MATH_MATRIX_CHECK */

  {
    /* Total number of samples in input matrix */
    numSamples = (uint32_t) pSrcA->numRows * pSrcA->numCols;

#if defined (ARM_MATH_LOOPUNROLL)

    /* Loop unrolling: Compute 4 outputs at a time */
    blkCnt = numSamples >> 2U;

    while (blkCnt > 0U)
    {
      /* C(m,n) = A(m,n) - B(m,n) */

      /* Subtract, Saturate and store result in destination buffer. */
#if defined (ARM_MATH_DSP)
      write_q15x2_ia (&pOut, __QSUB16(read_q15x2_ia ((q15_t **) &pInA), read_q15x2_ia ((q15_t **) &pInB)));
      write_q15x2_ia (&pOut, __QSUB16(read_q15x2_ia ((q15_t **) &pInA), read_q15x2_ia ((q15_t **) &pInB)));
#else
      *pOut++ = (q15_t) __SSAT(((q31_t) * pInA++ - *pInB++), 16);
      *pOut++ = (q15_t) __SSAT(((q31_t) * pInA++ - *pInB++), 16);
      *pOut++ = (q15_t) __SSAT(((q31_t) * pInA++ - *pInB++), 16);
      *pOut++ = (q15_t) __SSAT(((q31_t) * pInA++ - *pInB++), 16);
#endif

      /* Decrement loop counter */
      blkCnt--;
    }

    /* Loop unrolling: Compute remaining outputs */
    blkCnt = numSamples % 0x4U;

#else

    /* Initialize blkCnt with number of samples */
    blkCnt = numSamples;

#endif /* #if defined (ARM_MATH_LOOPUNROLL) */

    while (blkCnt > 0U)
    {
      /* C(m,n) = A(m,n) - B(m,n) */

      /* Subtract and store result in destination buffer. */
#if defined (ARM_MATH_DSP)
      *pOut++ = (q15_t) __QSUB16(*pInA++, *pInB++);
#else
      *pOut++ = (q15_t) __SSAT(((q31_t) * pInA++ - *pInB++), 16);
#endif

      /* Decrement loop counter */
      blkCnt--;
    }

    /* Set status as ARM_MATH_SUCCESS */
    status = ARM_MATH_SUCCESS;
  }

  /* Return to application */
  return (status);
}

/**
  @} end of MatrixSub group
 */