tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/StatisticsFunctions/arm_min_q31.c

   1 /* ----------------------------------------------------------------------
   2 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.
   3 *
   4 * $Date:        17. January 2013
   5 * $Revision:    V1.4.1
   6 *
   7 * Project:          CMSIS DSP Library
   8 * Title:                arm_min_q31.c
   9 *
  10 * Description:  Minimum value of a Q31 vector.
  11 *
  12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
  13 *
  14 * Redistribution and use in source and binary forms, with or without
  15 * modification, are permitted provided that the following conditions
  16 * are met:
  17 *   - Redistributions of source code must retain the above copyright
  18 *     notice, this list of conditions and the following disclaimer.
  19 *   - Redistributions in binary form must reproduce the above copyright
  20 *     notice, this list of conditions and the following disclaimer in
  21 *     the documentation and/or other materials provided with the
  22 *     distribution.
  23 *   - Neither the name of ARM LIMITED nor the names of its contributors
  24 *     may be used to endorse or promote products derived from this
  25 *     software without specific prior written permission.
  26 *
  27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  30 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  31 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  33 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  34 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  35 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  38 * POSSIBILITY OF SUCH DAMAGE.
  39 * ---------------------------------------------------------------------------- */
  40
  41 #include "arm_math.h"
  42
  43 /**
  44  * @ingroup groupStats
  45  */
  46
  47
  48 /**
  49  * @addtogroup Min
  50  * @{
  51  */
  52
  53
  54 /**
  55  * @brief Minimum value of a Q31 vector.
  56  * @param[in]       *pSrc points to the input vector
  57  * @param[in]       blockSize length of the input vector
  58  * @param[out]      *pResult minimum value returned here
  59  * @param[out]      *pIndex index of minimum value returned here
  60  * @return none.
  61  *
  62  */
  63
  64 void arm_min_q31(
  65   q31_t * pSrc,
  66   uint32_t blockSize,
  67   q31_t * pResult,
  68   uint32_t * pIndex)
  69 {
  70 #ifndef ARM_MATH_CM0_FAMILY
  71
  72   /* Run the below code for Cortex-M4 and Cortex-M3 */
  73   q31_t minVal1, minVal2, out;                   /* Temporary variables to store the output value. */
  74   uint32_t blkCnt, outIndex, count;              /* loop counter */
  75
  76   /* Initialise the count value. */
  77   count = 0u;
  78   /* Initialise the index value to zero. */
  79   outIndex = 0u;
  80   /* Load first input value that act as reference value for comparision */
  81   out = *pSrc++;
  82
  83
  84   /* Loop unrolling */
  85   blkCnt = (blockSize - 1u) >> 2u;
  86
  87   while(blkCnt > 0)
  88   {
  89     /* Initialize minVal to the next consecutive values one by one */
  90     minVal1 = *pSrc++;
  91     minVal2 = *pSrc++;
  92
  93     /* compare for the minimum value */
  94     if(out > minVal1)
  95     {
  96       /* Update the minimum value and its index */
  97       out = minVal1;
  98       outIndex = count + 1u;
  99     }
 100
 101     minVal1 = *pSrc++;
 102
 103     /* compare for the minimum value */
 104     if(out > minVal2)
 105     {
 106       /* Update the minimum value and its index */
 107       out = minVal2;
 108       outIndex = count + 2u;
 109     }
 110
 111     minVal2 = *pSrc++;
 112
 113     /* compare for the minimum value */
 114     if(out > minVal1)
 115     {
 116       /* Update the minimum value and its index */
 117       out = minVal1;
 118       outIndex = count + 3u;
 119     }
 120
 121     /* compare for the minimum value */
 122     if(out > minVal2)
 123     {
 124       /* Update the minimum value and its index */
 125       out = minVal2;
 126       outIndex = count + 4u;
 127     }
 128
 129     count += 4u;
 130
 131     blkCnt--;
 132   }
 133
 134   /* if (blockSize - 1u ) is not multiple of 4 */
 135   blkCnt = (blockSize - 1u) % 4u;
 136
 137 #else
 138
 139   /* Run the below code for Cortex-M0 */
 140   q31_t minVal1, out;                            /* Temporary variables to store the output value. */
 141   uint32_t blkCnt, outIndex;                     /* loop counter */
 142
 143   blkCnt = (blockSize - 1u);
 144
 145   /* Initialise the index value to zero. */
 146   outIndex = 0u;
 147   /* Load first input value that act as reference value for comparision */
 148   out = *pSrc++;
 149
 150 #endif //      #ifndef ARM_MATH_CM0_FAMILY
 151
 152   while(blkCnt > 0)
 153   {
 154     /* Initialize minVal to the next consecutive values one by one */
 155     minVal1 = *pSrc++;
 156
 157     /* compare for the minimum value */
 158     if(out > minVal1)
 159     {
 160       /* Update the minimum value and it's index */
 161       out = minVal1;
 162       outIndex = blockSize - blkCnt;
 163     }
 164
 165     blkCnt--;
 166
 167   }
 168
 169   /* Store the minimum value and its index into destination pointers */
 170   *pResult = out;
 171   *pIndex = outIndex;
 172 }
 173
 174 /**
 175  * @} end of Min group
 176  */