diff options
Diffstat (limited to 'fw/hid-dials/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_std_q15.c')
| -rw-r--r-- | fw/hid-dials/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_std_q15.c | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/fw/hid-dials/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_std_q15.c b/fw/hid-dials/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_std_q15.c new file mode 100644 index 0000000..e3626d8 --- /dev/null +++ b/fw/hid-dials/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_std_q15.c @@ -0,0 +1,174 @@ +/* ----------------------------------------------------------------------
+ * Project: CMSIS DSP Library
+ * Title: arm_std_q15.c
+ * Description: Standard deviation of an array of Q15 vector
+ *
+ * $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 STD
+ * @{
+ */
+
+/**
+ * @brief Standard deviation of the elements of a Q15 vector.
+ * @param[in] *pSrc points to the input vector
+ * @param[in] blockSize length of the input vector
+ * @param[out] *pResult standard deviation value returned here
+ * @return none.
+ * @details
+ * <b>Scaling and Overflow Behavior:</b>
+ *
+ * \par
+ * The function is implemented using a 64-bit internal accumulator.
+ * The input is represented in 1.15 format.
+ * Intermediate multiplication yields a 2.30 format, and this
+ * result is added without saturation to a 64-bit accumulator in 34.30 format.
+ * With 33 guard bits in the accumulator, there is no risk of overflow, and the
+ * full precision of the intermediate multiplication is preserved.
+ * Finally, the 34.30 result is truncated to 34.15 format by discarding the lower
+ * 15 bits, and then saturated to yield a result in 1.15 format.
+ */
+
+void arm_std_q15(
+ q15_t * pSrc,
+ uint32_t blockSize,
+ q15_t * pResult)
+{
+ q31_t sum = 0; /* Accumulator */
+ q31_t meanOfSquares, squareOfMean; /* square of mean and mean of square */
+ uint32_t blkCnt; /* loop counter */
+ q63_t sumOfSquares = 0; /* Accumulator */
+#if defined (ARM_MATH_DSP)
+ q31_t in; /* input value */
+ q15_t in1; /* input value */
+#else
+ q15_t in; /* input value */
+#endif
+
+ 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 = *__SIMD32(pSrc)++;
+ sum += ((in << 16U) >> 16U);
+ sum += (in >> 16U);
+ sumOfSquares = __SMLALD(in, in, sumOfSquares);
+ in = *__SIMD32(pSrc)++;
+ sum += ((in << 16U) >> 16U);
+ sum += (in >> 16U);
+ sumOfSquares = __SMLALD(in, in, sumOfSquares);
+
+ /* 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. */
+ in1 = *pSrc++;
+ sumOfSquares = __SMLALD(in1, in1, sumOfSquares);
+ sum += in1;
+
+ /* Decrement the loop counter */
+ blkCnt--;
+ }
+
+ /* Compute Mean of squares of the input samples
+ * and then store the result in a temporary variable, meanOfSquares. */
+ meanOfSquares = (q31_t)(sumOfSquares / (q63_t)(blockSize - 1U));
+
+ /* Compute square of mean */
+ squareOfMean = (q31_t)((q63_t)sum * sum / (q63_t)(blockSize * (blockSize - 1U)));
+
+ /* mean of the squares minus the square of the mean. */
+ /* Compute standard deviation and store the result to the destination */
+ arm_sqrt_q15(__SSAT((meanOfSquares - squareOfMean) >> 15U, 16U), pResult);
+
+#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++;
+ sumOfSquares += (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 = (q31_t)(sumOfSquares / (q63_t)(blockSize - 1U));
+
+ /* Compute square of mean */
+ squareOfMean = (q31_t)((q63_t)sum * sum / (q63_t)(blockSize * (blockSize - 1U)));
+
+ /* mean of the squares minus the square of the mean. */
+ /* Compute standard deviation and store the result to the destination */
+ arm_sqrt_q15(__SSAT((meanOfSquares - squareOfMean) >> 15U, 16U), pResult);
+
+#endif /* #if defined (ARM_MATH_DSP) */
+}
+
+/**
+ * @} end of STD group
+ */
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