mbed official / mbed-dsp

CMSIS DSP library

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cmsis_dsp/StatisticsFunctions/arm_rms_f32.c@2:da51fb522205, 2013-05-30 (annotated)

Committer:
emilmont
Date:
Thu May 30 17:10:11 2013 +0100
Revision:
2:da51fb522205
Parent:
1:fdd22bb7aa52
Child:
3:7a284390b0ce
Keep "cmsis-dsp" module in synch with its source

Who changed what in which revision?

UserRevisionLine numberNew 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 2:da51fb522205 5 * $Revision: V1.1.0
emilmont 1:fdd22bb7aa52 6 *
emilmont 2:da51fb522205 7 * Project: CMSIS DSP Library
emilmont 2:da51fb522205 8 * Title: arm_rms_f32.c
emilmont 1:fdd22bb7aa52 9 *
emilmont 2:da51fb522205 10 * Description: Root mean square value of an array of F32 type
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 * @defgroup RMS Root mean square (RMS)
emilmont 1:fdd22bb7aa52 41 *
emilmont 1:fdd22bb7aa52 42 *
emilmont 1:fdd22bb7aa52 43 * Calculates the Root Mean Sqaure of the elements in the input vector.
emilmont 1:fdd22bb7aa52 44 * The underlying algorithm is used:
emilmont 1:fdd22bb7aa52 45 *
emilmont 1:fdd22bb7aa52 46 * <pre>
emilmont 2:da51fb522205 47 * Result = sqrt(((pSrc[0] * pSrc[0] + pSrc[1] * pSrc[1] + ... + pSrc[blockSize-1] * pSrc[blockSize-1]) / blockSize));
emilmont 1:fdd22bb7aa52 48 * </pre>
emilmont 1:fdd22bb7aa52 49 *
emilmont 1:fdd22bb7aa52 50 * There are separate functions for floating point, Q31, and Q15 data types.
emilmont 1:fdd22bb7aa52 51 */
emilmont 1:fdd22bb7aa52 52
emilmont 1:fdd22bb7aa52 53 /**
emilmont 1:fdd22bb7aa52 54 * @addtogroup RMS
emilmont 1:fdd22bb7aa52 55 * @{
emilmont 1:fdd22bb7aa52 56 */
emilmont 1:fdd22bb7aa52 57
emilmont 1:fdd22bb7aa52 58
emilmont 1:fdd22bb7aa52 59 /**
emilmont 1:fdd22bb7aa52 60 * @brief Root Mean Square of the elements of a floating-point vector.
emilmont 1:fdd22bb7aa52 61 * @param[in] *pSrc points to the input vector
emilmont 1:fdd22bb7aa52 62 * @param[in] blockSize length of the input vector
emilmont 1:fdd22bb7aa52 63 * @param[out] *pResult rms value returned here
emilmont 1:fdd22bb7aa52 64 * @return none.
emilmont 1:fdd22bb7aa52 65 *
emilmont 1:fdd22bb7aa52 66 */
emilmont 1:fdd22bb7aa52 67
emilmont 1:fdd22bb7aa52 68 void arm_rms_f32(
emilmont 1:fdd22bb7aa52 69 float32_t * pSrc,
emilmont 1:fdd22bb7aa52 70 uint32_t blockSize,
emilmont 1:fdd22bb7aa52 71 float32_t * pResult)
emilmont 1:fdd22bb7aa52 72 {
emilmont 1:fdd22bb7aa52 73 float32_t sum = 0.0f; /* Accumulator */
emilmont 1:fdd22bb7aa52 74 float32_t in; /* Tempoprary variable to store input value */
emilmont 1:fdd22bb7aa52 75 uint32_t blkCnt; /* loop counter */
emilmont 1:fdd22bb7aa52 76
emilmont 1:fdd22bb7aa52 77 #ifndef ARM_MATH_CM0
emilmont 1:fdd22bb7aa52 78
emilmont 1:fdd22bb7aa52 79 /* Run the below code for Cortex-M4 and Cortex-M3 */
emilmont 1:fdd22bb7aa52 80
emilmont 1:fdd22bb7aa52 81 /* loop Unrolling */
emilmont 1:fdd22bb7aa52 82 blkCnt = blockSize >> 2u;
emilmont 1:fdd22bb7aa52 83
emilmont 1:fdd22bb7aa52 84 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
emilmont 1:fdd22bb7aa52 85 ** a second loop below computes the remaining 1 to 3 samples. */
emilmont 1:fdd22bb7aa52 86 while(blkCnt > 0u)
emilmont 1:fdd22bb7aa52 87 {
emilmont 1:fdd22bb7aa52 88 /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */
emilmont 1:fdd22bb7aa52 89 /* Compute sum of the squares and then store the result in a temporary variable, sum */
emilmont 1:fdd22bb7aa52 90 in = *pSrc++;
emilmont 1:fdd22bb7aa52 91 sum += in * in;
emilmont 1:fdd22bb7aa52 92 in = *pSrc++;
emilmont 1:fdd22bb7aa52 93 sum += in * in;
emilmont 1:fdd22bb7aa52 94 in = *pSrc++;
emilmont 1:fdd22bb7aa52 95 sum += in * in;
emilmont 1:fdd22bb7aa52 96 in = *pSrc++;
emilmont 1:fdd22bb7aa52 97 sum += in * in;
emilmont 1:fdd22bb7aa52 98
emilmont 1:fdd22bb7aa52 99 /* Decrement the loop counter */
emilmont 1:fdd22bb7aa52 100 blkCnt--;
emilmont 1:fdd22bb7aa52 101 }
emilmont 1:fdd22bb7aa52 102
emilmont 1:fdd22bb7aa52 103 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
emilmont 1:fdd22bb7aa52 104 ** No loop unrolling is used. */
emilmont 1:fdd22bb7aa52 105 blkCnt = blockSize % 0x4u;
emilmont 1:fdd22bb7aa52 106
emilmont 1:fdd22bb7aa52 107 #else
emilmont 1:fdd22bb7aa52 108
emilmont 1:fdd22bb7aa52 109 /* Run the below code for Cortex-M0 */
emilmont 1:fdd22bb7aa52 110
emilmont 1:fdd22bb7aa52 111 /* Loop over blockSize number of values */
emilmont 1:fdd22bb7aa52 112 blkCnt = blockSize;
emilmont 1:fdd22bb7aa52 113
emilmont 1:fdd22bb7aa52 114 #endif /* #ifndef ARM_MATH_CM0 */
emilmont 1:fdd22bb7aa52 115
emilmont 1:fdd22bb7aa52 116 while(blkCnt > 0u)
emilmont 1:fdd22bb7aa52 117 {
emilmont 1:fdd22bb7aa52 118 /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */
emilmont 1:fdd22bb7aa52 119 /* Compute sum of the squares and then store the results in a temporary variable, sum */
emilmont 1:fdd22bb7aa52 120 in = *pSrc++;
emilmont 1:fdd22bb7aa52 121 sum += in * in;
emilmont 1:fdd22bb7aa52 122
emilmont 1:fdd22bb7aa52 123 /* Decrement the loop counter */
emilmont 1:fdd22bb7aa52 124 blkCnt--;
emilmont 1:fdd22bb7aa52 125 }
emilmont 1:fdd22bb7aa52 126
emilmont 1:fdd22bb7aa52 127 /* Compute Rms and store the result in the destination */
emilmont 1:fdd22bb7aa52 128 arm_sqrt_f32(sum / (float32_t) blockSize, pResult);
emilmont 1:fdd22bb7aa52 129 }
emilmont 1:fdd22bb7aa52 130
emilmont 1:fdd22bb7aa52 131 /**
emilmont 1:fdd22bb7aa52 132 * @} end of RMS group
emilmont 1:fdd22bb7aa52 133 */