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Diffstat (limited to 'apps/mathlib/CMSIS/DSP_Lib/Source/StatisticsFunctions/arm_power_q31.c')
-rw-r--r-- | apps/mathlib/CMSIS/DSP_Lib/Source/StatisticsFunctions/arm_power_q31.c | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/apps/mathlib/CMSIS/DSP_Lib/Source/StatisticsFunctions/arm_power_q31.c b/apps/mathlib/CMSIS/DSP_Lib/Source/StatisticsFunctions/arm_power_q31.c new file mode 100644 index 000000000..43f03f757 --- /dev/null +++ b/apps/mathlib/CMSIS/DSP_Lib/Source/StatisticsFunctions/arm_power_q31.c @@ -0,0 +1,135 @@ +/* ----------------------------------------------------------------------
+* Copyright (C) 2010 ARM Limited. All rights reserved.
+*
+* $Date: 15. February 2012
+* $Revision: V1.1.0
+*
+* Project: CMSIS DSP Library
+* Title: arm_power_q31.c
+*
+* Description: Sum of the squares of the elements of a Q31 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"
+
+/**
+ * @ingroup groupStats
+ */
+
+/**
+ * @addtogroup power
+ * @{
+ */
+
+/**
+ * @brief Sum of the squares of the elements of a Q31 vector.
+ * @param[in] *pSrc points to the input vector
+ * @param[in] blockSize length of the input vector
+ * @param[out] *pResult sum of the squares 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 1.31 format.
+ * Intermediate multiplication yields a 2.62 format, and this
+ * result is truncated to 2.48 format by discarding the lower 14 bits.
+ * The 2.48 result is then added without saturation to a 64-bit accumulator in 16.48 format.
+ * With 15 guard bits in the accumulator, there is no risk of overflow, and the
+ * full precision of the intermediate multiplication is preserved.
+ * Finally, the return result is in 16.48 format.
+ *
+ */
+
+void arm_power_q31(
+ q31_t * pSrc,
+ uint32_t blockSize,
+ q63_t * pResult)
+{
+ q63_t sum = 0; /* Temporary result storage */
+ q31_t in;
+ uint32_t blkCnt; /* loop counter */
+
+
+#ifndef ARM_MATH_CM0
+
+ /* 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[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */
+ /* Compute Power then shift intermediate results by 14 bits to maintain 16.48 format and then store the result in a temporary variable sum, providing 15 guard bits. */
+ in = *pSrc++;
+ sum += ((q63_t) in * in) >> 14u;
+
+ in = *pSrc++;
+ sum += ((q63_t) in * in) >> 14u;
+
+ in = *pSrc++;
+ sum += ((q63_t) in * in) >> 14u;
+
+ in = *pSrc++;
+ sum += ((q63_t) in * in) >> 14u;
+
+ /* 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;
+
+#else
+
+ /* Run the below code for Cortex-M0 */
+
+ /* Loop over blockSize number of values */
+ blkCnt = blockSize;
+
+#endif /* #ifndef ARM_MATH_CM0 */
+
+ while(blkCnt > 0u)
+ {
+ /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */
+ /* Compute Power and then store the result in a temporary variable, sum. */
+ in = *pSrc++;
+ sum += ((q63_t) in * in) >> 14u;
+
+ /* Decrement the loop counter */
+ blkCnt--;
+ }
+
+ /* Store the results in 16.48 format */
+ *pResult = sum;
+}
+
+/**
+ * @} end of power group
+ */
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