From 86608c6770cf08c138a2bdab5855072f64be09ef Mon Sep 17 00:00:00 2001
From: joshua <joshua@joshuayun.com>
Date: Sat, 30 Dec 2023 23:54:31 -0500
Subject: initial commit

---
 .../DSP/Source/StatisticsFunctions/arm_rms_q31.c   | 124 +++++++++++++++++++++
 1 file changed, 124 insertions(+)
 create mode 100644 Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_rms_q31.c

(limited to 'Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_rms_q31.c')

diff --git a/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_rms_q31.c b/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_rms_q31.c
new file mode 100644
index 0000000..4cf086f
--- /dev/null
+++ b/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_rms_q31.c
@@ -0,0 +1,124 @@
+/* ----------------------------------------------------------------------
+ * Project:      CMSIS DSP Library
+ * Title:        arm_rms_q31.c
+ * Description:  Root Mean Square of the elements of a Q31 vector
+ *
+ * $Date:        18. March 2019
+ * $Revision:    V1.6.0
+ *
+ * Target Processor: Cortex-M cores
+ * -------------------------------------------------------------------- */
+/*
+ * Copyright (C) 2010-2019 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 RMS
+  @{
+ */
+
+/**
+  @brief         Root Mean Square 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    root mean square 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, and intermediate multiplication
+                   yields a 2.62 format.
+                   The accumulator maintains full precision of the intermediate multiplication results,
+                   but provides only a single guard bit.
+                   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) bits, as a total of blockSize additions are performed internally.
+                   Finally, the 2.62 accumulator is right shifted by 31 bits to yield a 1.31 format value.
+ */
+
+void arm_rms_q31(
+  const q31_t * pSrc,
+        uint32_t blockSize,
+        q31_t * pResult)
+{
+        uint32_t blkCnt;                               /* Loop counter */
+        uint64_t sum = 0;                              /* Temporary result storage (can get never negative. changed type from q63 to uint64 */
+        q31_t in;                                      /* Temporary variable to store input value */
+
+#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] */
+
+    in = *pSrc++;
+    /* Compute sum of squares and store result in a temporary variable, sum. */
+    sum += ((q63_t) in * in);
+
+    in = *pSrc++;
+    sum += ((q63_t) in * in);
+
+    in = *pSrc++;
+    sum += ((q63_t) in * in);
+
+    in = *pSrc++;
+    sum += ((q63_t) in * 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] */
+
+    in = *pSrc++;
+    /* Compute sum of squares and store result in a temporary variable. */
+    sum += ((q63_t) in * in);
+
+    /* Decrement loop counter */
+    blkCnt--;
+  }
+
+  /* Convert data in 2.62 to 1.31 by 31 right shifts and saturate */
+  /* Compute Rms and store result in destination vector */
+  arm_sqrt_q31(clip_q63_to_q31((sum / (q63_t) blockSize) >> 31), pResult);
+}
+
+/**
+  @} end of RMS group
+ */
-- 
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