arm_rms_f32.c
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r16 | /* ---------------------------------------------------------------------- | ||
| * Copyright (C) 2010 ARM Limited. All rights reserved. | ||||
| * | ||||
| * $Date: 29. November 2010 | ||||
| * $Revision: V1.0.3 | ||||
| * | ||||
| * 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 | ||||
| * | ||||
| * 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 */ | ||||
| /* 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; | ||||
| 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 | ||||
| */ | ||||