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_mean_q15.c 00009 * 00010 * Description: Mean value of a Q15 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 00061 void arm_mean_q15( 00062 q15_t * pSrc, 00063 uint32_t blockSize, 00064 q15_t * pResult) 00065 { 00066 q31_t sum = 0; /* Temporary result storage */ 00067 uint32_t blkCnt; /* loop counter */ 00068 00069 #ifndef ARM_MATH_CM0 00070 00071 /* Run the below code for Cortex-M4 and Cortex-M3 */ 00072 00073 /*loop Unrolling */ 00074 blkCnt = blockSize >> 2u; 00075 00076 /* First part of the processing with loop unrolling. Compute 4 outputs at a time. 00077 ** a second loop below computes the remaining 1 to 3 samples. */ 00078 while(blkCnt > 0u) 00079 { 00080 /* C = (A[0] + A[1] + A[2] + ... + A[blockSize-1]) */ 00081 sum += *pSrc++; 00082 sum += *pSrc++; 00083 sum += *pSrc++; 00084 sum += *pSrc++; 00085 00086 /* Decrement the loop counter */ 00087 blkCnt--; 00088 } 00089 00090 /* If the blockSize is not a multiple of 4, compute any remaining output samples here. 00091 ** No loop unrolling is used. */ 00092 blkCnt = blockSize % 0x4u; 00093 00094 #else 00095 00096 /* Run the below code for Cortex-M0 */ 00097 00098 /* Loop over blockSize number of values */ 00099 blkCnt = blockSize; 00100 00101 #endif /* #ifndef ARM_MATH_CM0 */ 00102 00103 while(blkCnt > 0u) 00104 { 00105 /* C = (A[0] + A[1] + A[2] + ... + A[blockSize-1]) */ 00106 sum += *pSrc++; 00107 00108 /* Decrement the loop counter */ 00109 blkCnt--; 00110 } 00111 00112 /* C = (A[0] + A[1] + A[2] + ... + A[blockSize-1]) / blockSize */ 00113 /* Store the result to the destination */ 00114 *pResult = (q15_t) (sum / blockSize); 00115 } 00116