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cmsis_dsp/StatisticsFunctions/arm_mean_q7.c@1:fdd22bb7aa52, 2012-11-28 (annotated)
- Committer:
- emilmont
- Date:
- Wed Nov 28 12:30:09 2012 +0000
- Revision:
- 1:fdd22bb7aa52
- Child:
- 2:da51fb522205
DSP library code
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
emilmont | 1:fdd22bb7aa52 | 1 | /* ---------------------------------------------------------------------- |
emilmont | 1:fdd22bb7aa52 | 2 | * Copyright (C) 2010 ARM Limited. All rights reserved. |
emilmont | 1:fdd22bb7aa52 | 3 | * |
emilmont | 1:fdd22bb7aa52 | 4 | * $Date: 15. February 2012 |
emilmont | 1:fdd22bb7aa52 | 5 | * $Revision: V1.1.0 |
emilmont | 1:fdd22bb7aa52 | 6 | * |
emilmont | 1:fdd22bb7aa52 | 7 | * Project: CMSIS DSP Library |
emilmont | 1:fdd22bb7aa52 | 8 | * Title: arm_mean_q7.c |
emilmont | 1:fdd22bb7aa52 | 9 | * |
emilmont | 1:fdd22bb7aa52 | 10 | * Description: Mean value of a Q7 vector. |
emilmont | 1:fdd22bb7aa52 | 11 | * |
emilmont | 1:fdd22bb7aa52 | 12 | * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 |
emilmont | 1:fdd22bb7aa52 | 13 | * |
emilmont | 1:fdd22bb7aa52 | 14 | * Version 1.1.0 2012/02/15 |
emilmont | 1:fdd22bb7aa52 | 15 | * Updated with more optimizations, bug fixes and minor API changes. |
emilmont | 1:fdd22bb7aa52 | 16 | * |
emilmont | 1:fdd22bb7aa52 | 17 | * Version 1.0.10 2011/7/15 |
emilmont | 1:fdd22bb7aa52 | 18 | * Big Endian support added and Merged M0 and M3/M4 Source code. |
emilmont | 1:fdd22bb7aa52 | 19 | * |
emilmont | 1:fdd22bb7aa52 | 20 | * Version 1.0.3 2010/11/29 |
emilmont | 1:fdd22bb7aa52 | 21 | * Re-organized the CMSIS folders and updated documentation. |
emilmont | 1:fdd22bb7aa52 | 22 | * |
emilmont | 1:fdd22bb7aa52 | 23 | * Version 1.0.2 2010/11/11 |
emilmont | 1:fdd22bb7aa52 | 24 | * Documentation updated. |
emilmont | 1:fdd22bb7aa52 | 25 | * |
emilmont | 1:fdd22bb7aa52 | 26 | * Version 1.0.1 2010/10/05 |
emilmont | 1:fdd22bb7aa52 | 27 | * Production release and review comments incorporated. |
emilmont | 1:fdd22bb7aa52 | 28 | * |
emilmont | 1:fdd22bb7aa52 | 29 | * Version 1.0.0 2010/09/20 |
emilmont | 1:fdd22bb7aa52 | 30 | * Production release and review comments incorporated. |
emilmont | 1:fdd22bb7aa52 | 31 | * -------------------------------------------------------------------- */ |
emilmont | 1:fdd22bb7aa52 | 32 | |
emilmont | 1:fdd22bb7aa52 | 33 | #include "arm_math.h" |
emilmont | 1:fdd22bb7aa52 | 34 | |
emilmont | 1:fdd22bb7aa52 | 35 | /** |
emilmont | 1:fdd22bb7aa52 | 36 | * @ingroup groupStats |
emilmont | 1:fdd22bb7aa52 | 37 | */ |
emilmont | 1:fdd22bb7aa52 | 38 | |
emilmont | 1:fdd22bb7aa52 | 39 | /** |
emilmont | 1:fdd22bb7aa52 | 40 | * @addtogroup mean |
emilmont | 1:fdd22bb7aa52 | 41 | * @{ |
emilmont | 1:fdd22bb7aa52 | 42 | */ |
emilmont | 1:fdd22bb7aa52 | 43 | |
emilmont | 1:fdd22bb7aa52 | 44 | /** |
emilmont | 1:fdd22bb7aa52 | 45 | * @brief Mean value of a Q7 vector. |
emilmont | 1:fdd22bb7aa52 | 46 | * @param[in] *pSrc points to the input vector |
emilmont | 1:fdd22bb7aa52 | 47 | * @param[in] blockSize length of the input vector |
emilmont | 1:fdd22bb7aa52 | 48 | * @param[out] *pResult mean value returned here |
emilmont | 1:fdd22bb7aa52 | 49 | * @return none. |
emilmont | 1:fdd22bb7aa52 | 50 | * |
emilmont | 1:fdd22bb7aa52 | 51 | * @details |
emilmont | 1:fdd22bb7aa52 | 52 | * <b>Scaling and Overflow Behavior:</b> |
emilmont | 1:fdd22bb7aa52 | 53 | * \par |
emilmont | 1:fdd22bb7aa52 | 54 | * The function is implemented using a 32-bit internal accumulator. |
emilmont | 1:fdd22bb7aa52 | 55 | * The input is represented in 1.7 format and is accumulated in a 32-bit |
emilmont | 1:fdd22bb7aa52 | 56 | * accumulator in 25.7 format. |
emilmont | 1:fdd22bb7aa52 | 57 | * There is no risk of internal overflow with this approach, and the |
emilmont | 1:fdd22bb7aa52 | 58 | * full precision of intermediate result is preserved. |
emilmont | 1:fdd22bb7aa52 | 59 | * Finally, the accumulator is truncated to yield a result of 1.7 format. |
emilmont | 1:fdd22bb7aa52 | 60 | * |
emilmont | 1:fdd22bb7aa52 | 61 | */ |
emilmont | 1:fdd22bb7aa52 | 62 | |
emilmont | 1:fdd22bb7aa52 | 63 | |
emilmont | 1:fdd22bb7aa52 | 64 | void arm_mean_q7( |
emilmont | 1:fdd22bb7aa52 | 65 | q7_t * pSrc, |
emilmont | 1:fdd22bb7aa52 | 66 | uint32_t blockSize, |
emilmont | 1:fdd22bb7aa52 | 67 | q7_t * pResult) |
emilmont | 1:fdd22bb7aa52 | 68 | { |
emilmont | 1:fdd22bb7aa52 | 69 | q31_t sum = 0; /* Temporary result storage */ |
emilmont | 1:fdd22bb7aa52 | 70 | uint32_t blkCnt; /* loop counter */ |
emilmont | 1:fdd22bb7aa52 | 71 | |
emilmont | 1:fdd22bb7aa52 | 72 | #ifndef ARM_MATH_CM0 |
emilmont | 1:fdd22bb7aa52 | 73 | |
emilmont | 1:fdd22bb7aa52 | 74 | /* Run the below code for Cortex-M4 and Cortex-M3 */ |
emilmont | 1:fdd22bb7aa52 | 75 | q31_t in; |
emilmont | 1:fdd22bb7aa52 | 76 | |
emilmont | 1:fdd22bb7aa52 | 77 | /*loop Unrolling */ |
emilmont | 1:fdd22bb7aa52 | 78 | blkCnt = blockSize >> 2u; |
emilmont | 1:fdd22bb7aa52 | 79 | |
emilmont | 1:fdd22bb7aa52 | 80 | /* First part of the processing with loop unrolling. Compute 4 outputs at a time. |
emilmont | 1:fdd22bb7aa52 | 81 | ** a second loop below computes the remaining 1 to 3 samples. */ |
emilmont | 1:fdd22bb7aa52 | 82 | while(blkCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 83 | { |
emilmont | 1:fdd22bb7aa52 | 84 | /* C = (A[0] + A[1] + A[2] + ... + A[blockSize-1]) */ |
emilmont | 1:fdd22bb7aa52 | 85 | in = *__SIMD32(pSrc)++; |
emilmont | 1:fdd22bb7aa52 | 86 | |
emilmont | 1:fdd22bb7aa52 | 87 | sum += ((in << 24) >> 24); |
emilmont | 1:fdd22bb7aa52 | 88 | sum += ((in << 16) >> 24); |
emilmont | 1:fdd22bb7aa52 | 89 | sum += ((in << 8) >> 24); |
emilmont | 1:fdd22bb7aa52 | 90 | sum += (in >> 24); |
emilmont | 1:fdd22bb7aa52 | 91 | |
emilmont | 1:fdd22bb7aa52 | 92 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 93 | blkCnt--; |
emilmont | 1:fdd22bb7aa52 | 94 | } |
emilmont | 1:fdd22bb7aa52 | 95 | |
emilmont | 1:fdd22bb7aa52 | 96 | /* If the blockSize is not a multiple of 4, compute any remaining output samples here. |
emilmont | 1:fdd22bb7aa52 | 97 | ** No loop unrolling is used. */ |
emilmont | 1:fdd22bb7aa52 | 98 | blkCnt = blockSize % 0x4u; |
emilmont | 1:fdd22bb7aa52 | 99 | |
emilmont | 1:fdd22bb7aa52 | 100 | #else |
emilmont | 1:fdd22bb7aa52 | 101 | |
emilmont | 1:fdd22bb7aa52 | 102 | /* Run the below code for Cortex-M0 */ |
emilmont | 1:fdd22bb7aa52 | 103 | |
emilmont | 1:fdd22bb7aa52 | 104 | /* Loop over blockSize number of values */ |
emilmont | 1:fdd22bb7aa52 | 105 | blkCnt = blockSize; |
emilmont | 1:fdd22bb7aa52 | 106 | |
emilmont | 1:fdd22bb7aa52 | 107 | #endif /* #ifndef ARM_MATH_CM0 */ |
emilmont | 1:fdd22bb7aa52 | 108 | |
emilmont | 1:fdd22bb7aa52 | 109 | while(blkCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 110 | { |
emilmont | 1:fdd22bb7aa52 | 111 | /* C = (A[0] + A[1] + A[2] + ... + A[blockSize-1]) */ |
emilmont | 1:fdd22bb7aa52 | 112 | sum += *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 113 | |
emilmont | 1:fdd22bb7aa52 | 114 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 115 | blkCnt--; |
emilmont | 1:fdd22bb7aa52 | 116 | } |
emilmont | 1:fdd22bb7aa52 | 117 | |
emilmont | 1:fdd22bb7aa52 | 118 | /* C = (A[0] + A[1] + A[2] + ... + A[blockSize-1]) / blockSize */ |
emilmont | 1:fdd22bb7aa52 | 119 | /* Store the result to the destination */ |
emilmont | 1:fdd22bb7aa52 | 120 | *pResult = (q7_t) (sum / (int32_t) blockSize); |
emilmont | 1:fdd22bb7aa52 | 121 | } |
emilmont | 1:fdd22bb7aa52 | 122 | |
emilmont | 1:fdd22bb7aa52 | 123 | /** |
emilmont | 1:fdd22bb7aa52 | 124 | * @} end of mean group |
emilmont | 1:fdd22bb7aa52 | 125 | */ |