arm_max_f32.c

00001 /* ----------------------------------------------------------------------  
00002 * Copyright (C) 2010 ARM Limited. All rights reserved.  
00003 *  
00004 * $Date:        29. November 2010  
00005 * $Revision:    V1.0.3  
00006 *  
00007 * Project:      CMSIS DSP Library  
00008 * Title:        arm_max_f32.c  
00009 *  
00010 * Description:  Maximum value of a floating-point vector.  
00011 *  
00012 * Target Processor: Cortex-M4/Cortex-M3
00013 *  
00014 * Version 1.0.3 2010/11/29 
00015 *    Re-organized the CMSIS folders and updated documentation.  
00016 *   
00017 * Version 1.0.2 2010/11/11  
00018 *    Documentation updated.   
00019 *  
00020 * Version 1.0.1 2010/10/05   
00021 *    Production release and review comments incorporated.  
00022 *  
00023 * Version 1.0.0 2010/09/20   
00024 *    Production release and review comments incorporated.  
00025 * ---------------------------------------------------------------------------- */ 
00026  
00027 #include "arm_math.h" 
00028  
00029 /**  
00030  * @ingroup groupStats  
00031  */ 
00032  
00033 /**  
00034  * @defgroup Max Maximum  
00035  *  
00036  * Computes the maximum value of an array of data.   
00037  * The function returns both the maximum value and its position within the array.   
00038  * There are separate functions for floating-point, Q31, Q15, and Q7 data types.  
00039  */ 
00040  
00041 /**  
00042  * @addtogroup Max  
00043  * @{  
00044  */ 
00045  
00046  
00047 /**  
00048  * @brief Maximum value of a floating-point vector.  
00049  * @param[in]       *pSrc points to the input vector  
00050  * @param[in]       blockSize length of the input vector  
00051  * @param[out]      *pResult maximum value returned here  
00052  * @param[out]      *pIndex index of maximum value returned here  
00053  * @return none.  
00054  */ 
00055  
00056 void arm_max_f32( 
00057   float32_t * pSrc, 
00058   uint32_t blockSize, 
00059   float32_t * pResult, 
00060   uint32_t * pIndex) 
00061 { 
00062   float32_t maxVal, out;                         /* Temporary variables to store the output value. */ 
00063   uint32_t blkCnt, outIndex;                     /* loop counter */ 
00064  
00065   /* Initialise the index value to zero. */ 
00066   outIndex = 0u; 
00067   /* Load first input value that act as reference value for comparision */ 
00068   out = *pSrc++; 
00069  
00070   /* Loop over blockSize number of values */ 
00071   blkCnt = (blockSize - 1u); 
00072  
00073   do 
00074   { 
00075     /* Initialize maxVal to the next consecutive values one by one */ 
00076     maxVal = *pSrc++; 
00077  
00078     /* compare for the maximum value */ 
00079     if(out < maxVal) 
00080     { 
00081       /* Update the maximum value and it's index */ 
00082       out = maxVal; 
00083       outIndex = blockSize - blkCnt; 
00084     } 
00085  
00086     blkCnt--; 
00087  
00088   } while(blkCnt > 0u); 
00089  
00090   /* Store the maximum value and it's index into destination pointers */ 
00091   *pResult = out; 
00092   *pIndex = outIndex; 
00093 } 
00094  
00095 /**  
00096  * @} end of Max group  
00097  */