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author | px4dev <px4@purgatory.org> | 2013-01-06 12:52:05 -0800 |
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committer | px4dev <px4@purgatory.org> | 2013-01-06 12:52:05 -0800 |
commit | 4447282260be0780eb6e36f5e953bf56888a5688 (patch) | |
tree | 3ba1e976d998d433397343b79a0612af52075aef /apps/mathlib/CMSIS/DSP_Lib/Source/StatisticsFunctions/arm_rms_q15.c | |
parent | 659543f852d18197f68fafee5db5671567b74f4b (diff) | |
download | px4-firmware-4447282260be0780eb6e36f5e953bf56888a5688.tar.gz px4-firmware-4447282260be0780eb6e36f5e953bf56888a5688.tar.bz2 px4-firmware-4447282260be0780eb6e36f5e953bf56888a5688.zip |
Integrate the interesting parts of the CMSIS 3.01 (r3p1) DSP library
Diffstat (limited to 'apps/mathlib/CMSIS/DSP_Lib/Source/StatisticsFunctions/arm_rms_q15.c')
-rw-r--r-- | apps/mathlib/CMSIS/DSP_Lib/Source/StatisticsFunctions/arm_rms_q15.c | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/apps/mathlib/CMSIS/DSP_Lib/Source/StatisticsFunctions/arm_rms_q15.c b/apps/mathlib/CMSIS/DSP_Lib/Source/StatisticsFunctions/arm_rms_q15.c new file mode 100644 index 000000000..491c652e7 --- /dev/null +++ b/apps/mathlib/CMSIS/DSP_Lib/Source/StatisticsFunctions/arm_rms_q15.c @@ -0,0 +1,153 @@ +/* ----------------------------------------------------------------------
+* Copyright (C) 2010 ARM Limited. All rights reserved.
+*
+* $Date: 15. February 2012
+* $Revision: V1.1.0
+*
+* Project: CMSIS DSP Library
+* Title: arm_rms_q15.c
+*
+* Description: Root Mean Square of the elements of a Q15 vector.
+*
+* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
+*
+* Version 1.1.0 2012/02/15
+* Updated with more optimizations, bug fixes and minor API changes.
+*
+* Version 1.0.10 2011/7/15
+* Big Endian support added and Merged M0 and M3/M4 Source code.
+*
+* Version 1.0.3 2010/11/29
+* Re-organized the CMSIS folders and updated documentation.
+*
+* Version 1.0.2 2010/11/11
+* Documentation updated.
+*
+* Version 1.0.1 2010/10/05
+* Production release and review comments incorporated.
+*
+* Version 1.0.0 2010/09/20
+* Production release and review comments incorporated.
+* ---------------------------------------------------------------------------- */
+
+#include "arm_math.h"
+
+/**
+ * @addtogroup RMS
+ * @{
+ */
+
+/**
+ * @brief Root Mean Square 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 rms 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_rms_q15(
+ q15_t * pSrc,
+ uint32_t blockSize,
+ q15_t * pResult)
+{
+ q63_t sum = 0; /* accumulator */
+
+#ifndef ARM_MATH_CM0
+
+ /* Run the below code for Cortex-M4 and Cortex-M3 */
+
+ q31_t in; /* temporary variable to store the input value */
+ q15_t in1; /* temporary variable to store the input value */
+ uint32_t blkCnt; /* loop counter */
+
+ /* 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 the squares and then store the results in a temporary variable, sum */
+ in = *__SIMD32(pSrc)++;
+ sum = __SMLALD(in, in, sum);
+ in = *__SIMD32(pSrc)++;
+ sum = __SMLALD(in, in, sum);
+
+ /* 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 the squares and then store the results in a temporary variable, sum */
+ in1 = *pSrc++;
+ sum = __SMLALD(in1, in1, sum);
+
+ /* Decrement the loop counter */
+ blkCnt--;
+ }
+
+ /* Truncating and saturating the accumulator to 1.15 format */
+ sum = __SSAT((q31_t) (sum >> 15), 16);
+
+ in1 = (q15_t) (sum / blockSize);
+
+ /* Store the result in the destination */
+ arm_sqrt_q15(in1, pResult);
+
+#else
+
+ /* Run the below code for Cortex-M0 */
+
+ q15_t in; /* temporary variable to store the input value */
+ uint32_t blkCnt; /* loop counter */
+
+ /* 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 the squares and then store the results in a temporary variable, sum */
+ in = *pSrc++;
+ sum += ((q31_t) in * in);
+
+ /* Decrement the loop counter */
+ blkCnt--;
+ }
+
+ /* Truncating and saturating the accumulator to 1.15 format */
+ sum = __SSAT((q31_t) (sum >> 15), 16);
+
+ in = (q15_t) (sum / blockSize);
+
+ /* Store the result in the destination */
+ arm_sqrt_q15(in, pResult);
+
+#endif /* #ifndef ARM_MATH_CM0 */
+
+}
+
+/**
+ * @} end of RMS group
+ */
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