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  1. /* ----------------------------------------------------------------------    
  2. * Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
  3. *    
  4. * $Date:        19. March 2015
  5. * $Revision:    V.1.4.5  
  6. *    
  7. * Project:          CMSIS DSP Library    
  8. * Title:                arm_min_f32.c    
  9. *    
  10. * Description:  Minimum value of a floating-point 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.  * @defgroup Min Minimum    
  49.  *    
  50.  * Computes the minimum value of an array of data.    
  51.  * The function returns both the minimum value and its position within the array.    
  52.  * There are separate functions for floating-point, Q31, Q15, and Q7 data types.    
  53.  */
  54.  
  55. /**    
  56.  * @addtogroup Min    
  57.  * @{    
  58.  */
  59.  
  60.  
  61. /**    
  62.  * @brief Minimum value of a floating-point vector.    
  63.  * @param[in]       *pSrc points to the input vector    
  64.  * @param[in]       blockSize length of the input vector    
  65.  * @param[out]      *pResult minimum value returned here    
  66.  * @param[out]      *pIndex index of minimum value returned here    
  67.   * @return none.    
  68.  *    
  69.  */
  70.  
  71. void arm_min_f32(
  72.   float32_t * pSrc,
  73.   uint32_t blockSize,
  74.   float32_t * pResult,
  75.   uint32_t * pIndex)
  76. {
  77. #ifndef ARM_MATH_CM0_FAMILY
  78.  
  79.   /* Run the below code for Cortex-M4 and Cortex-M3 */
  80.  
  81.   float32_t minVal1, minVal2, out;               /* Temporary variables to store the output value. */
  82.   uint32_t blkCnt, outIndex, count;              /* loop counter */
  83.  
  84.   /* Initialise the count value. */
  85.   count = 0u;
  86.   /* Initialise the index value to zero. */
  87.   outIndex = 0u;
  88.   /* Load first input value that act as reference value for comparision */
  89.   out = *pSrc++;
  90.  
  91.   /* Loop unrolling */
  92.   blkCnt = (blockSize - 1u) >> 2u;
  93.  
  94.   while(blkCnt > 0)
  95.   {
  96.     /* Initialize minVal to the next consecutive values one by one */
  97.     minVal1 = *pSrc++;
  98.     minVal2 = *pSrc++;
  99.  
  100.     /* compare for the minimum value */
  101.     if(out > minVal1)
  102.     {
  103.       /* Update the minimum value and its index */
  104.       out = minVal1;
  105.       outIndex = count + 1u;
  106.     }
  107.  
  108.     minVal1 = *pSrc++;
  109.  
  110.     /* compare for the minimum value */
  111.     if(out > minVal2)
  112.     {
  113.       /* Update the minimum value and its index */
  114.       out = minVal2;
  115.       outIndex = count + 2u;
  116.     }
  117.  
  118.     minVal2 = *pSrc++;
  119.  
  120.     /* compare for the minimum value */
  121.     if(out > minVal1)
  122.     {
  123.       /* Update the minimum value and its index */
  124.       out = minVal1;
  125.       outIndex = count + 3u;
  126.     }
  127.  
  128.     /* compare for the minimum value */
  129.     if(out > minVal2)
  130.     {
  131.       /* Update the minimum value and its index */
  132.       out = minVal2;
  133.       outIndex = count + 4u;
  134.     }
  135.  
  136.     count += 4u;
  137.  
  138.     blkCnt--;
  139.   }
  140.  
  141.   /* if (blockSize - 1u ) is not multiple of 4 */
  142.   blkCnt = (blockSize - 1u) % 4u;
  143.  
  144. #else
  145.  
  146.   /* Run the below code for Cortex-M0 */
  147.   float32_t minVal1, out;                        /* Temporary variables to store the output value. */
  148.   uint32_t blkCnt, outIndex;                     /* loop counter */
  149.  
  150.   /* Initialise the index value to zero. */
  151.   outIndex = 0u;
  152.   /* Load first input value that act as reference value for comparision */
  153.   out = *pSrc++;
  154.  
  155.   blkCnt = (blockSize - 1u);
  156.  
  157. #endif //      #ifndef ARM_MATH_CM0_FAMILY
  158.  
  159.   while(blkCnt > 0)
  160.   {
  161.     /* Initialize minVal to the next consecutive values one by one */
  162.     minVal1 = *pSrc++;
  163.  
  164.     /* compare for the minimum value */
  165.     if(out > minVal1)
  166.     {
  167.       /* Update the minimum value and it's index */
  168.       out = minVal1;
  169.       outIndex = blockSize - blkCnt;
  170.     }
  171.  
  172.     blkCnt--;
  173.  
  174.   }
  175.  
  176.   /* Store the minimum value and it's index into destination pointers */
  177.   *pResult = out;
  178.   *pIndex = outIndex;
  179. }
  180.  
  181. /**    
  182.  * @} end of Min group    
  183.  */
  184.