1  /* ----------------------------------------------------------------------
 2   * Project:      CMSIS DSP Library
 3   * Title:        arm_max_f64.c
 4   * Description:  Maximum value of a floating-point vector
 5   *
 6   * $Date:        13 September 2021
 7   * $Revision:    V1.10.0
 8   *
 9   * Target Processor: Cortex-M and Cortex-A cores
10   * -------------------------------------------------------------------- */
11  /*
12   * Copyright (C) 2010-2021 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 "dsp/statistics_functions.h"
30  
31  /**
32    @ingroup groupStats
33   */
34  
35  /**
36    @addtogroup Max
37    @{
38   */
39  
40  /**
41    @brief         Maximum value of a floating-point vector.
42    @param[in]     pSrc       points to the input vector
43    @param[in]     blockSize  number of samples in input vector
44    @param[out]    pResult    maximum value returned here
45    @param[out]    pIndex     index of maximum value returned here
46    @return        none
47   */
48  void arm_max_f64(
49    const float64_t * pSrc,
50          uint32_t blockSize,
51          float64_t * pResult,
52          uint32_t * pIndex)
53  {
54          float64_t maxVal, out;                         /* Temporary variables to store the output value. */
55          uint32_t blkCnt, outIndex;                     /* Loop counter */
56  
57    /* Initialise index value to zero. */
58    outIndex = 0U;
59  
60    /* Load first input value that act as reference value for comparision */
61    out = *pSrc++;
62  
63    /* Initialize blkCnt with number of samples */
64    blkCnt = (blockSize - 1U);
65  
66    while (blkCnt > 0U)
67    {
68      /* Initialize maxVal to the next consecutive values one by one */
69      maxVal = *pSrc++;
70  
71      /* compare for the maximum value */
72      if (out < maxVal)
73      {
74        /* Update the maximum value and it's index */
75        out = maxVal;
76        outIndex = blockSize - blkCnt;
77      }
78  
79      /* Decrement loop counter */
80      blkCnt--;
81    }
82  
83    /* Store the maximum value and it's index into destination pointers */
84    *pResult = out;
85    *pIndex = outIndex;
86  }
87  
88  /**
89    @} end of Max group
90   */