initial commit

1 files changed, 214 insertions, 0 deletions

diff --git a/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_var_q31.c b/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_var_q31.c
new file mode 100644
index 0000000..45b6b66
--- /dev/null
+++ b/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_var_q31.c
@@ -0,0 +1,214 @@
+/* ----------------------------------------------------------------------
+ * Project:      CMSIS DSP Library
+ * Title:        arm_var_q31.c
+ * Description:  Variance of an array of Q31 type
+ *
+ * $Date:        23 April 2021
+ * $Revision:    V1.9.0
+ *
+ * Target Processor: Cortex-M and Cortex-A cores
+ * -------------------------------------------------------------------- */
+/*
+ * Copyright (C) 2010-2021 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 "dsp/statistics_functions.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  number of samples in input vector
+  @param[out]    pResult    variance value returned here
+  @return        none
+
+  @par           Scaling and Overflow Behavior
+                   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,
+                   and as a consequence has only 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.
+ */
+#if defined(ARM_MATH_MVEI) && !defined(ARM_MATH_AUTOVECTORIZE)
+void arm_var_q31(
+  const q31_t * pSrc,
+        uint32_t blockSize,
+        q31_t * pResult)
+{
+    uint32_t  blkCnt;     /* loop counters */
+    q31x4_t         vecSrc;
+    q63_t           sumOfSquares = 0LL;
+    q63_t           meanOfSquares, squareOfMean;        /* square of mean and mean of square */
+    q63_t           sum = 0LL;
+    q31_t in; 
+
+    if (blockSize <= 1U) {
+        *pResult = 0;
+        return;
+    }
+
+
+   /* Compute 4 outputs at a time */
+    blkCnt = blockSize >> 2U;
+    while (blkCnt > 0U)
+    {
+        vecSrc = vldrwq_s32(pSrc);
+        /* 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. */
+
+        /* downscale */
+        vecSrc = vshrq(vecSrc, 8);
+        sumOfSquares = vmlaldavaq(sumOfSquares, vecSrc, vecSrc);
+        sum = vaddlvaq(sum, vecSrc);
+
+        blkCnt --;
+        pSrc += 4;
+    }
+
+    
+    /*
+     * tail
+     */
+    blkCnt = blockSize & 0x3;
+    while (blkCnt > 0U)
+    {
+       /* C = A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1] */
+       /* C = A[0] + A[1] + ... + A[blockSize-1] */
+
+       in = *pSrc++ >> 8U;
+       /* Compute sum of squares and store result in a temporary variable, sumOfSquares. */
+       sumOfSquares += ((q63_t) (in) * (in));
+       /* Compute sum and store result in a temporary variable, sum. */
+       sum += in;
+   
+       /* Decrement 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);
+
+    /* Compute square of mean */
+    squareOfMean = sum * sum / (q63_t) (blockSize * (blockSize - 1U));
+
+    /* Compute standard deviation and then store the result to the destination */
+    *pResult = asrl(meanOfSquares - squareOfMean, 15U);
+}
+#else
+void arm_var_q31(
+  const q31_t * pSrc,
+        uint32_t blockSize,
+        q31_t * pResult)
+{
+        uint32_t blkCnt;                               /* Loop counter */
+        q63_t sum = 0;                                 /* Temporary result storage */
+        q63_t meanOfSquares, squareOfMean;             /* Square of mean and mean of square */
+        q63_t sumOfSquares = 0;                        /* Sum of squares */
+        q31_t in;                                      /* Temporary variable to store input value */
+
+  if (blockSize <= 1U)
+  {
+    *pResult = 0;
+    return;
+  }
+
+#if defined (ARM_MATH_LOOPUNROLL)
+
+  /* Loop unrolling: Compute 4 outputs at a time */
+  blkCnt = blockSize >> 2U;
+
+  while (blkCnt > 0U)
+  {
+    /* C = A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1] */
+    /* C = A[0] + A[1] + ... + A[blockSize-1] */
+
+    in = *pSrc++ >> 8U;
+    /* Compute sum of squares and store result in a temporary variable, sumOfSquares. */
+    sumOfSquares += ((q63_t) (in) * (in));
+    /* Compute sum and store result in a temporary variable, sum. */
+    sum += in;
+
+    in = *pSrc++ >> 8U;
+    sumOfSquares += ((q63_t) (in) * (in));
+    sum += in;
+
+    in = *pSrc++ >> 8U;
+    sumOfSquares += ((q63_t) (in) * (in));
+    sum += in;
+
+    in = *pSrc++ >> 8U;
+    sumOfSquares += ((q63_t) (in) * (in));
+    sum += in;
+
+    /* Decrement loop counter */
+    blkCnt--;
+  }
+
+  /* Loop unrolling: Compute remaining outputs */
+  blkCnt = blockSize % 0x4U;
+
+#else
+
+  /* Initialize blkCnt with number of samples */
+  blkCnt = blockSize;
+
+#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
+
+  while (blkCnt > 0U)
+  {
+    /* C = A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1] */
+    /* C = A[0] + A[1] + ... + A[blockSize-1] */
+
+    in = *pSrc++ >> 8U;
+    /* Compute sum of squares and store result in a temporary variable, sumOfSquares. */
+    sumOfSquares += ((q63_t) (in) * (in));
+    /* Compute sum and store result in a temporary variable, sum. */
+    sum += in;
+
+    /* Decrement loop counter */
+    blkCnt--;
+  }
+
+  /* Compute Mean of squares and store result in a temporary variable, meanOfSquares. */
+  meanOfSquares = (sumOfSquares / (q63_t)(blockSize - 1U));
+
+  /* Compute square of mean */
+  squareOfMean = ( sum * sum / (q63_t)(blockSize * (blockSize - 1U)));
+
+  /* Compute variance and store result in destination */
+  *pResult = (meanOfSquares - squareOfMean) >> 15U;
+}
+#endif
+/**
+  @} end of variance group
+ */