arm_min_f32.c

00001 /* ----------------------------------------------------------------------    
00002 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.    
00003 *    
00004 * $Date:        17. January 2013
00005 * $Revision:    V1.4.1  
00006 *    
00007 * Project:      CMSIS DSP Library    
00008 * Title:        arm_min_f32.c    
00009 *    
00010 * Description:  Minimum value of a floating-point vector.    
00011 *    
00012 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
00013 *  
00014 * Redistribution and use in source and binary forms, with or without 
00015 * modification, are permitted provided that the following conditions
00016 * are met:
00017 *   - Redistributions of source code must retain the above copyright
00018 *     notice, this list of conditions and the following disclaimer.
00019 *   - Redistributions in binary form must reproduce the above copyright
00020 *     notice, this list of conditions and the following disclaimer in
00021 *     the documentation and/or other materials provided with the 
00022 *     distribution.
00023 *   - Neither the name of ARM LIMITED nor the names of its contributors
00024 *     may be used to endorse or promote products derived from this
00025 *     software without specific prior written permission.
00026 *
00027 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00028 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00029 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
00030 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
00031 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
00032 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
00033 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
00034 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
00035 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00036 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
00037 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
00038 * POSSIBILITY OF SUCH DAMAGE.     
00039 * ---------------------------------------------------------------------------- */
00040 
00041 #include "arm_math.h"
00042 
00043 /**    
00044  * @ingroup groupStats    
00045  */
00046 
00047 /**    
00048  * @defgroup Min Minimum    
00049  *    
00050  * Computes the minimum value of an array of data.     
00051  * The function returns both the minimum value and its position within the array.     
00052  * There are separate functions for floating-point, Q31, Q15, and Q7 data types.    
00053  */
00054 
00055 /**    
00056  * @addtogroup Min    
00057  * @{    
00058  */
00059 
00060 
00061 /**    
00062  * @brief Minimum value of a floating-point vector.    
00063  * @param[in]       *pSrc points to the input vector    
00064  * @param[in]       blockSize length of the input vector    
00065  * @param[out]      *pResult minimum value returned here    
00066  * @param[out]      *pIndex index of minimum value returned here    
00067   * @return none.    
00068  *    
00069  */
00070 
00071 void arm_min_f32(
00072   float32_t * pSrc,
00073   uint32_t blockSize,
00074   float32_t * pResult,
00075   uint32_t * pIndex)
00076 {
00077 #ifndef ARM_MATH_CM0_FAMILY
00078 
00079   /* Run the below code for Cortex-M4 and Cortex-M3 */
00080 
00081   float32_t minVal1, minVal2, out;               /* Temporary variables to store the output value. */
00082   uint32_t blkCnt, outIndex, count;              /* loop counter */
00083 
00084   /* Initialise the count value. */
00085   count = 0u;
00086   /* Initialise the index value to zero. */
00087   outIndex = 0u;
00088   /* Load first input value that act as reference value for comparision */
00089   out = *pSrc++;
00090 
00091   /* Loop unrolling */
00092   blkCnt = (blockSize - 1u) >> 2u;
00093 
00094   while(blkCnt > 0)
00095   {
00096     /* Initialize minVal to the next consecutive values one by one */
00097     minVal1 = *pSrc++;
00098     minVal2 = *pSrc++;
00099 
00100     /* compare for the minimum value */
00101     if(out > minVal1)
00102     {
00103       /* Update the minimum value and its index */
00104       out = minVal1;
00105       outIndex = count + 1u;
00106     }
00107 
00108     minVal1 = *pSrc++;
00109 
00110     /* compare for the minimum value */
00111     if(out > minVal2)
00112     {
00113       /* Update the minimum value and its index */
00114       out = minVal2;
00115       outIndex = count + 2u;
00116     }
00117 
00118     minVal2 = *pSrc++;
00119 
00120     /* compare for the minimum value */
00121     if(out > minVal1)
00122     {
00123       /* Update the minimum value and its index */
00124       out = minVal1;
00125       outIndex = count + 3u;
00126     }
00127 
00128     /* compare for the minimum value */
00129     if(out > minVal2)
00130     {
00131       /* Update the minimum value and its index */
00132       out = minVal2;
00133       outIndex = count + 4u;
00134     }
00135 
00136     count += 4u;
00137 
00138     blkCnt--;
00139   }
00140 
00141   /* if (blockSize - 1u ) is not multiple of 4 */
00142   blkCnt = (blockSize - 1u) % 4u;
00143 
00144 #else
00145 
00146   /* Run the below code for Cortex-M0 */
00147   float32_t minVal1, out;                        /* Temporary variables to store the output value. */
00148   uint32_t blkCnt, outIndex;                     /* loop counter */
00149 
00150   /* Initialise the index value to zero. */
00151   outIndex = 0u;
00152   /* Load first input value that act as reference value for comparision */
00153   out = *pSrc++;
00154 
00155   blkCnt = (blockSize - 1u);
00156 
00157 #endif //      #ifndef ARM_MATH_CM0_FAMILY
00158 
00159   while(blkCnt > 0)
00160   {
00161     /* Initialize minVal to the next consecutive values one by one */
00162     minVal1 = *pSrc++;
00163 
00164     /* compare for the minimum value */
00165     if(out > minVal1)
00166     {
00167       /* Update the minimum value and it's index */
00168       out = minVal1;
00169       outIndex = blockSize - blkCnt;
00170     }
00171 
00172     blkCnt--;
00173 
00174   }
00175 
00176   /* Store the minimum value and it's index into destination pointers */
00177   *pResult = out;
00178   *pIndex = outIndex;
00179 }
00180 
00181 /**    
00182  * @} end of Min group    
00183  */