| /* ---------------------------------------------------------------------- |
| * Copyright (C) 2010 ARM Limited. All rights reserved. |
| * |
| * $Date: 15. July 2011 |
| * $Revision: V1.0.10 |
| * |
| * Project: CMSIS DSP Library |
| * Title: arm_rms_f32.c |
| * |
| * Description: Root mean square value of an array of F32 type |
| * |
| * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 |
| * |
| * Version 1.0.10 2011/7/15 |
| * Big Endian support added and Merged M0 and M3/M4 Source code. |
| * |
| * Version 1.0.3 2010/11/29 |
| * Re-organized the CMSIS folders and updated documentation. |
| * |
| * Version 1.0.2 2010/11/11 |
| * Documentation updated. |
| * |
| * Version 1.0.1 2010/10/05 |
| * Production release and review comments incorporated. |
| * |
| * Version 1.0.0 2010/09/20 |
| * Production release and review comments incorporated. |
| * ---------------------------------------------------------------------------- */ |
| |
| #include "arm_math.h" |
| |
| /** |
| * @ingroup groupStats |
| */ |
| |
| /** |
| * @defgroup RMS Root mean square (RMS) |
| * |
| * |
| * Calculates the Root Mean Sqaure of the elements in the input vector. |
| * The underlying algorithm is used: |
| * |
| * <pre> |
| * Result = sqrt(((pSrc[0] * pSrc[0] + pSrc[1] * pSrc[1] + ... + pSrc[blockSize-1] * pSrc[blockSize-1]) / blockSize)); |
| * </pre> |
| * |
| * There are separate functions for floating point, Q31, and Q15 data types. |
| */ |
| |
| /** |
| * @addtogroup RMS |
| * @{ |
| */ |
| |
| |
| /** |
| * @brief Root Mean Square of the elements of a floating-point vector. |
| * @param[in] *pSrc points to the input vector |
| * @param[in] blockSize length of the input vector |
| * @param[out] *pResult rms value returned here |
| * @return none. |
| * |
| */ |
| |
| void arm_rms_f32( |
| float32_t * pSrc, |
| uint32_t blockSize, |
| float32_t * pResult) |
| { |
| float32_t sum = 0.0f; /* Accumulator */ |
| float32_t in; /* Tempoprary variable to store input value */ |
| uint32_t blkCnt; /* loop counter */ |
| |
| #ifndef ARM_MATH_CM0 |
| |
| /* Run the below code for Cortex-M4 and Cortex-M3 */ |
| |
| /* loop Unrolling */ |
| blkCnt = blockSize >> 2u; |
| |
| /* First part of the processing with loop unrolling. Compute 4 outputs at a time. |
| ** a second loop below computes the remaining 1 to 3 samples. */ |
| while(blkCnt > 0u) |
| { |
| /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */ |
| /* Compute sum of the squares and then store the result in a temporary variable, sum */ |
| in = *pSrc++; |
| sum += in * in; |
| in = *pSrc++; |
| sum += in * in; |
| in = *pSrc++; |
| sum += in * in; |
| in = *pSrc++; |
| sum += in * in; |
| |
| /* Decrement the loop counter */ |
| blkCnt--; |
| } |
| |
| /* If the blockSize is not a multiple of 4, compute any remaining output samples here. |
| ** No loop unrolling is used. */ |
| blkCnt = blockSize % 0x4u; |
| |
| #else |
| |
| /* Run the below code for Cortex-M0 */ |
| |
| /* Loop over blockSize number of values */ |
| blkCnt = blockSize; |
| |
| #endif /* #ifndef ARM_MATH_CM0 */ |
| |
| while(blkCnt > 0u) |
| { |
| /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */ |
| /* Compute sum of the squares and then store the results in a temporary variable, sum */ |
| in = *pSrc++; |
| sum += in * in; |
| |
| /* Decrement the loop counter */ |
| blkCnt--; |
| } |
| |
| /* Compute Rms and store the result in the destination */ |
| arm_sqrt_f32(sum / (float32_t) blockSize, pResult); |
| } |
| |
| /** |
| * @} end of RMS group |
| */ |