tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/StatisticsFunctions/arm_min_q15.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_q15.c
   9 *
  10 * Description:  Minimum value of a Q15 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 Q15 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_q15(
  65   q15_t * pSrc,
  66   uint32_t blockSize,
  67   q15_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   q15_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   /* Loop unrolling */
  84   blkCnt = (blockSize - 1u) >> 2u;
  85
  86   while(blkCnt > 0)
  87   {
  88     /* Initialize minVal to the next consecutive values one by one */
  89     minVal1 = *pSrc++;
  90     minVal2 = *pSrc++;
  91
  92     /* compare for the minimum value */
  93     if(out > minVal1)
  94     {
  95       /* Update the minimum value and its index */
  96       out = minVal1;
  97       outIndex = count + 1u;
  98     }
  99
 100     minVal1 = *pSrc++;
 101
 102     /* compare for the minimum value */
 103     if(out > minVal2)
 104     {
 105       /* Update the minimum value and its index */
 106       out = minVal2;
 107       outIndex = count + 2u;
 108     }
 109
 110     minVal2 = *pSrc++;
 111
 112     /* compare for the minimum value */
 113     if(out > minVal1)
 114     {
 115       /* Update the minimum value and its index */
 116       out = minVal1;
 117       outIndex = count + 3u;
 118     }
 119
 120     /* compare for the minimum value */
 121     if(out > minVal2)
 122     {
 123       /* Update the minimum value and its index */
 124       out = minVal2;
 125       outIndex = count + 4u;
 126     }
 127
 128     count += 4u;
 129
 130     blkCnt--;
 131   }
 132
 133   /* if (blockSize - 1u ) is not multiple of 4 */
 134   blkCnt = (blockSize - 1u) % 4u;
 135
 136 #else
 137
 138   /* Run the below code for Cortex-M0 */
 139   q15_t minVal1, out;                            /* Temporary variables to store the output value. */
 140   uint32_t blkCnt, outIndex;                     /* loop counter */
 141
 142   blkCnt = (blockSize - 1u);
 143
 144   /* Initialise the index value to zero. */
 145   outIndex = 0u;
 146   /* Load first input value that act as reference value for comparision */
 147   out = *pSrc++;
 148
 149 #endif //      #ifndef ARM_MATH_CM0_FAMILY
 150
 151   while(blkCnt > 0)
 152   {
 153     /* Initialize minVal to the next consecutive values one by one */
 154     minVal1 = *pSrc++;
 155
 156     /* compare for the minimum value */
 157     if(out > minVal1)
 158     {
 159       /* Update the minimum value and it's index */
 160       out = minVal1;
 161       outIndex = blockSize - blkCnt;
 162     }
 163
 164     blkCnt--;
 165
 166   }
 167
 168
 169
 170   /* Store the minimum value and its index into destination pointers */
 171   *pResult = out;
 172   *pIndex = outIndex;
 173 }
 174
 175 /**
 176  * @} end of Min group
 177  */