00001 /* ---------------------------------------------------------------------- 00002 * Copyright (C) 2010 ARM Limited. All rights reserved. 00003 * 00004 * $Date: 15. July 2011 00005 * $Revision: V1.0.10 00006 * 00007 * Project: CMSIS DSP Library 00008 * Title: arm_max_q31.c 00009 * 00010 * Description: Maximum value of a Q31 vector. 00011 * 00012 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 00013 * 00014 * Version 1.0.10 2011/7/15 00015 * Big Endian support added and Merged M0 and M3/M4 Source code. 00016 * 00017 * Version 1.0.3 2010/11/29 00018 * Re-organized the CMSIS folders and updated documentation. 00019 * 00020 * Version 1.0.2 2010/11/11 00021 * Documentation updated. 00022 * 00023 * Version 1.0.1 2010/10/05 00024 * Production release and review comments incorporated. 00025 * 00026 * Version 1.0.0 2010/09/20 00027 * Production release and review comments incorporated. 00028 * ---------------------------------------------------------------------------- */ 00029 00030 #include "arm_math.h" 00031 00051 void arm_max_q31( 00052 q31_t * pSrc, 00053 uint32_t blockSize, 00054 q31_t * pResult, 00055 uint32_t * pIndex) 00056 { 00057 q31_t maxVal, out; /* Temporary variables to store the output value. */ 00058 uint32_t blkCnt, outIndex; /* loop counter */ 00059 00060 /* Initialise the index value to zero. */ 00061 outIndex = 0u; 00062 /* Load first input value that act as reference value for comparision */ 00063 out = *pSrc++; 00064 00065 /* Loop over blockSize number of values */ 00066 blkCnt = (blockSize - 1u); 00067 00068 #ifndef ARM_MATH_CM0 00069 00070 /* Run the below code for Cortex-M4 and Cortex-M3 */ 00071 00072 do 00073 { 00074 /* Initialize maxVal to the next consecutive values one by one */ 00075 maxVal = *pSrc++; 00076 00077 /* compare for the maximum value */ 00078 if(out < maxVal) 00079 { 00080 /* Update the maximum value and its index */ 00081 out = maxVal; 00082 outIndex = blockSize - blkCnt; 00083 } 00084 00085 /* Decrement the loop counter */ 00086 blkCnt--; 00087 00088 } while(blkCnt > 0u); 00089 00090 #else 00091 00092 /* Run the below code for Cortex-M0 */ 00093 00094 while(blkCnt > 0u) 00095 { 00096 /* Initialize maxVal to the next consecutive values one by one */ 00097 maxVal = *pSrc++; 00098 00099 /* Compare for the maximum value */ 00100 if(out < maxVal) 00101 { 00102 /* Update the maximum value and its index */ 00103 out = maxVal; 00104 outIndex = blockSize - blkCnt; 00105 } 00106 00107 /* Decrement the loop counter */ 00108 blkCnt--; 00109 00110 } 00111 00112 #endif /* #ifndef ARM_MATH_CM0 */ 00113 00114 /* Store the maximum value and its index into destination pointers */ 00115 *pResult = out; 00116 *pIndex = outIndex; 00117 } 00118