diff options
Diffstat (limited to 'Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_power_q31.c')
| -rw-r--r-- | Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_power_q31.c | 92 |
1 files changed, 42 insertions, 50 deletions
diff --git a/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_power_q31.c b/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_power_q31.c index 16be24907..1e193b326 100644 --- a/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_power_q31.c +++ b/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_power_q31.c @@ -3,13 +3,13 @@ * Title: arm_power_q31.c * Description: Sum of the squares of the elements of a Q31 vector * - * $Date: 27. January 2017 - * $Revision: V.1.5.1 + * $Date: 18. March 2019 + * $Revision: V1.6.0 * * Target Processor: Cortex-M cores * -------------------------------------------------------------------- */ /* - * Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved. + * Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved. * * SPDX-License-Identifier: Apache-2.0 * @@ -29,58 +29,51 @@ #include "arm_math.h" /** - * @ingroup groupStats + @ingroup groupStats */ /** - * @addtogroup power - * @{ + @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. - * + @brief Sum of the squares 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 sum of the squares 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 1.31 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) + const q31_t * pSrc, + uint32_t blockSize, + q63_t * pResult) { - q63_t sum = 0; /* Temporary result storage */ - q31_t in; - uint32_t blkCnt; /* loop counter */ + uint32_t blkCnt; /* Loop counter */ + q63_t sum = 0; /* Temporary result storage */ + q31_t in; /* Temporary variable to store input value */ +#if defined (ARM_MATH_LOOPUNROLL) -#if defined (ARM_MATH_DSP) - /* Run the below code for Cortex-M4 and Cortex-M3 */ - - /*loop Unrolling */ + /* Loop unrolling: Compute 4 outputs at a time */ 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. */ + /* C = A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1] */ + + /* Compute Power then shift intermediate results by 14 bits to maintain 16.48 format and store result in a temporary variable sum, providing 15 guard bits. */ in = *pSrc++; sum += ((q63_t) in * in) >> 14U; @@ -93,37 +86,36 @@ void arm_power_q31( in = *pSrc++; sum += ((q63_t) in * in) >> 14U; - /* Decrement the loop counter */ + /* Decrement loop counter */ blkCnt--; } - /* If the blockSize is not a multiple of 4, compute any remaining output samples here. - ** No loop unrolling is used. */ + /* Loop unrolling: Compute remaining outputs */ blkCnt = blockSize % 0x4U; #else - /* Run the below code for Cortex-M0 */ - /* Loop over blockSize number of values */ + /* Initialize blkCnt with number of samples */ blkCnt = blockSize; -#endif /* #if defined (ARM_MATH_DSP) */ +#endif /* #if defined (ARM_MATH_LOOPUNROLL) */ 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. */ + /* C = A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1] */ + + /* Compute Power and store result in a temporary variable, sum. */ in = *pSrc++; sum += ((q63_t) in * in) >> 14U; - /* Decrement the loop counter */ + /* Decrement loop counter */ blkCnt--; } - /* Store the results in 16.48 format */ + /* Store results in 16.48 format */ *pResult = sum; } /** - * @} end of power group + @} end of power group */ |