From a81fc41c3eb99e8fc52aa734ee63e13c937aab81 Mon Sep 17 00:00:00 2001 From: JanHenrik Date: Sun, 19 Jan 2020 00:56:37 +0100 Subject: added blink example --- .../DSP/Source/StatisticsFunctions/arm_var_q31.c | 169 +++++++++++++++++++++ 1 file changed, 169 insertions(+) create mode 100644 Blink/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_var_q31.c (limited to 'Blink/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_var_q31.c') diff --git a/Blink/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_var_q31.c b/Blink/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_var_q31.c new file mode 100644 index 0000000..08e80fe --- /dev/null +++ b/Blink/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_var_q31.c @@ -0,0 +1,169 @@ +/* ---------------------------------------------------------------------- + * Project: CMSIS DSP Library + * Title: arm_var_q31.c + * Description: Variance of an array of Q31 type + * + * $Date: 27. January 2017 + * $Revision: V.1.5.1 + * + * Target Processor: Cortex-M cores + * -------------------------------------------------------------------- */ +/* + * Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved. + * + * SPDX-License-Identifier: Apache-2.0 + * + * Licensed under the Apache License, Version 2.0 (the License); you may + * not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an AS IS BASIS, WITHOUT + * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#include "arm_math.h" + +/** + * @ingroup groupStats + */ + +/** + * @addtogroup variance + * @{ + */ + +/** + * @brief Variance of the elements of a Q31 vector. + * @param[in] *pSrc points to the input vector + * @param[in] blockSize length of the input vector + * @param[out] *pResult variance value returned here + * @return none. + * @details + * Scaling and Overflow Behavior: + * + *\par + * The function is implemented using an internal 64-bit accumulator. + * The input is represented in 1.31 format, which is then downshifted by 8 bits + * which yields 1.23, and intermediate multiplication yields a 2.46 format. + * The accumulator maintains full precision of the intermediate multiplication results, + * but provides only a 16 guard bits. + * There is no saturation on intermediate additions. + * If the accumulator overflows it wraps around and distorts the result. + * In order to avoid overflows completely the input signal must be scaled down by + * log2(blockSize)-8 bits, as a total of blockSize additions are performed internally. + * After division, internal variables should be Q18.46 + * Finally, the 18.46 accumulator is right shifted by 15 bits to yield a 1.31 format value. + * + */ + +void arm_var_q31( + q31_t * pSrc, + uint32_t blockSize, + q31_t * pResult) +{ + q63_t sum = 0; /* Accumulator */ + q63_t meanOfSquares, squareOfMean; /* square of mean and mean of square */ + q31_t in; /* input value */ + uint32_t blkCnt; /* loop counter */ + q63_t sumOfSquares = 0; /* Accumulator */ + + if (blockSize == 1U) + { + *pResult = 0; + return; + } + +#if defined (ARM_MATH_DSP) + /* 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[blockSize-1] * A[blockSize-1]) */ + /* Compute Sum of squares of the input samples + * and then store the result in a temporary variable, sum. */ + in = *pSrc++ >> 8U; + sum += in; + sumOfSquares += ((q63_t) (in) * (in)); + in = *pSrc++ >> 8U; + sum += in; + sumOfSquares += ((q63_t) (in) * (in)); + in = *pSrc++ >> 8U; + sum += in; + sumOfSquares += ((q63_t) (in) * (in)); + in = *pSrc++ >> 8U; + sum += in; + sumOfSquares += ((q63_t) (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[blockSize-1] * A[blockSize-1]) */ + /* Compute Sum of squares of the input samples + * and then store the result in a temporary variable, sum. */ + in = *pSrc++ >> 8U; + sum += in; + sumOfSquares += ((q63_t) (in) * (in)); + + /* Decrement the loop counter */ + blkCnt--; + } + + /* Compute Mean of squares of the input samples + * and then store the result in a temporary variable, meanOfSquares. */ + meanOfSquares = sumOfSquares / (q63_t)(blockSize - 1U); + +#else + /* Run the below code for Cortex-M0 */ + + /* Loop over blockSize number of values */ + blkCnt = blockSize; + + while (blkCnt > 0U) + { + /* C = (A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1]) */ + /* Compute Sum of squares of the input samples + * and then store the result in a temporary variable, sumOfSquares. */ + in = *pSrc++ >> 8U; + sumOfSquares += ((q63_t) (in) * (in)); + + /* C = (A[0] + A[1] + A[2] + ... + A[blockSize-1]) */ + /* Compute sum of all input values and then store the result in a temporary variable, sum. */ + sum += in; + + /* Decrement the loop counter */ + blkCnt--; + } + + /* Compute Mean of squares of the input samples + * and then store the result in a temporary variable, meanOfSquares. */ + meanOfSquares = sumOfSquares / (q63_t)(blockSize - 1U); + +#endif /* #if defined (ARM_MATH_DSP) */ + + /* Compute square of mean */ + squareOfMean = sum * sum / (q63_t)(blockSize * (blockSize - 1U)); + + /* Compute standard deviation and then store the result to the destination */ + *pResult = (meanOfSquares - squareOfMean) >> 15U; +} + +/** + * @} end of variance group + */ -- cgit