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_q15.c   | 134 +++++++++++++++++++++
 1 file changed, 134 insertions(+)
 create mode 100644 Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_rms_q15.c

(limited to 'Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_rms_q15.c')

diff --git a/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_rms_q15.c b/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_rms_q15.c
new file mode 100644
index 0000000..c8a0a13
--- /dev/null
+++ b/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_rms_q15.c
@@ -0,0 +1,134 @@
+/* ----------------------------------------------------------------------
+ * Project:      CMSIS DSP Library
+ * Title:        arm_rms_q15.c
+ * Description:  Root Mean Square of the elements of a Q15 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 Q15 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 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_rms_q15(
+  const q15_t * pSrc,
+        uint32_t blockSize,
+        q15_t * pResult)
+{
+        uint32_t blkCnt;                               /* Loop counter */
+        q63_t sum = 0;                                 /* Temporary result storage */
+        q15_t in;                                      /* Temporary variable to store input value */
+
+#if defined (ARM_MATH_LOOPUNROLL) && defined (ARM_MATH_DSP)
+        q31_t in32;                                    /* Temporary variable to store input value */
+#endif
+
+#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] */
+
+    /* Compute sum of squares and store result in a temporary variable. */
+#if defined (ARM_MATH_DSP)
+    in32 = read_q15x2_ia ((q15_t **) &pSrc);
+    sum = __SMLALD(in32, in32, sum);
+
+    in32 = read_q15x2_ia ((q15_t **) &pSrc);
+    sum = __SMLALD(in32, in32, sum);
+#else
+    in = *pSrc++;
+    sum += ((q31_t) in * in);
+
+    in = *pSrc++;
+    sum += ((q31_t) in * in);
+
+    in = *pSrc++;
+    sum += ((q31_t) in * in);
+
+    in = *pSrc++;
+    sum += ((q31_t) in * in);
+#endif /* #if defined (ARM_MATH_DSP) */
+
+    /* 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 += ((q31_t) in * in);
+
+    /* Decrement loop counter */
+    blkCnt--;
+  }
+
+  /* Truncating and saturating the accumulator to 1.15 format */
+  /* Store result in destination */
+  arm_sqrt_q15(__SSAT((sum / (q63_t)blockSize) >> 15, 16), pResult);
+}
+
+/**
+  @} end of RMS group
+ */
-- 
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