mirror of
https://github.com/google/pebble.git
synced 2025-05-19 09:54:55 +00:00
Import of the watch repository from Pebble
This commit is contained in:
Matthieu Jeanson
Katharine Berry
commit
3b92768480
10334 changed files with 2564465 additions and 0 deletions
195
third_party/ARM/Source/StatisticsFunctions/arm_std_q15.c
vendored
Normal file
195
third_party/ARM/Source/StatisticsFunctions/arm_std_q15.c
vendored
Normal file
|
|
@ -0,0 +1,195 @@
|
|||
/* ----------------------------------------------------------------------
|
||||
* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
|
||||
*
|
||||
* $Date: 19. March 2015
|
||||
* $Revision: V.1.4.5
|
||||
*
|
||||
* Project: CMSIS DSP Library
|
||||
* Title: arm_std_q15.c
|
||||
*
|
||||
* Description: Standard deviation of an array of Q15 type.
|
||||
*
|
||||
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
|
||||
*
|
||||
* Redistribution and use in source and binary forms, with or without
|
||||
* modification, are permitted provided that the following conditions
|
||||
* are met:
|
||||
* - Redistributions of source code must retain the above copyright
|
||||
* notice, this list of conditions and the following disclaimer.
|
||||
* - Redistributions in binary form must reproduce the above copyright
|
||||
* notice, this list of conditions and the following disclaimer in
|
||||
* the documentation and/or other materials provided with the
|
||||
* distribution.
|
||||
* - Neither the name of ARM LIMITED nor the names of its contributors
|
||||
* may be used to endorse or promote products derived from this
|
||||
* software without specific prior written permission.
|
||||
*
|
||||
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
||||
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
||||
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
||||
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
||||
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
||||
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
|
||||
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
|
||||
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
|
||||
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
||||
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
|
||||
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
||||
* POSSIBILITY OF SUCH DAMAGE.
|
||||
* -------------------------------------------------------------------- */
|
||||
|
||||
#include "arm_math.h"
|
||||
|
||||
/**
|
||||
* @ingroup groupStats
|
||||
*/
|
||||
|
||||
/**
|
||||
* @addtogroup STD
|
||||
* @{
|
||||
*/
|
||||
|
||||
/**
|
||||
* @brief Standard deviation 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 standard deviation 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_std_q15(
|
||||
q15_t * pSrc,
|
||||
uint32_t blockSize,
|
||||
q15_t * pResult)
|
||||
{
|
||||
q31_t sum = 0; /* Accumulator */
|
||||
q31_t meanOfSquares, squareOfMean; /* square of mean and mean of square */
|
||||
uint32_t blkCnt; /* loop counter */
|
||||
q63_t sumOfSquares = 0; /* Accumulator */
|
||||
|
||||
#ifndef ARM_MATH_CM0_FAMILY
|
||||
|
||||
/* Run the below code for Cortex-M4 and Cortex-M3 */
|
||||
|
||||
q31_t in; /* input value */
|
||||
q15_t in1; /* input value */
|
||||
|
||||
if(blockSize == 1)
|
||||
{
|
||||
*pResult = 0;
|
||||
return;
|
||||
}
|
||||
|
||||
/*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 squares of the input samples
|
||||
* and then store the result in a temporary variable, sum. */
|
||||
in = *__SIMD32(pSrc)++;
|
||||
sum += ((in << 16) >> 16);
|
||||
sum += (in >> 16);
|
||||
sumOfSquares = __SMLALD(in, in, sumOfSquares);
|
||||
in = *__SIMD32(pSrc)++;
|
||||
sum += ((in << 16) >> 16);
|
||||
sum += (in >> 16);
|
||||
sumOfSquares = __SMLALD(in, in, sumOfSquares);
|
||||
|
||||
/* 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 squares of the input samples
|
||||
* and then store the result in a temporary variable, sum. */
|
||||
in1 = *pSrc++;
|
||||
sumOfSquares = __SMLALD(in1, in1, sumOfSquares);
|
||||
sum += in1;
|
||||
|
||||
/* Decrement the loop counter */
|
||||
blkCnt--;
|
||||
}
|
||||
|
||||
/* Compute Mean of squares of the input samples
|
||||
* and then store the result in a temporary variable, meanOfSquares. */
|
||||
meanOfSquares = (q31_t)(sumOfSquares / (q63_t)(blockSize - 1));
|
||||
|
||||
/* Compute square of mean */
|
||||
squareOfMean = (q31_t) ((q63_t)sum * sum / (q63_t)(blockSize * (blockSize - 1)));
|
||||
|
||||
/* mean of the squares minus the square of the mean. */
|
||||
/* Compute standard deviation and store the result to the destination */
|
||||
arm_sqrt_q15(__SSAT((meanOfSquares - squareOfMean) >> 15, 16u), pResult);
|
||||
|
||||
#else
|
||||
|
||||
/* Run the below code for Cortex-M0 */
|
||||
q15_t in; /* input value */
|
||||
|
||||
if(blockSize == 1)
|
||||
{
|
||||
*pResult = 0;
|
||||
return;
|
||||
}
|
||||
|
||||
/* 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 squares of the input samples
|
||||
* and then store the result in a temporary variable, sumOfSquares. */
|
||||
in = *pSrc++;
|
||||
sumOfSquares += (in * in);
|
||||
|
||||
/* C = (A[0] + A[1] + A[2] + ... + A[blockSize-1]) */
|
||||
/* Compute sum of all input values and then store the result in a temporary variable, sum. */
|
||||
sum += in;
|
||||
|
||||
/* Decrement the loop counter */
|
||||
blkCnt--;
|
||||
}
|
||||
|
||||
/* Compute Mean of squares of the input samples
|
||||
* and then store the result in a temporary variable, meanOfSquares. */
|
||||
meanOfSquares = (q31_t)(sumOfSquares / (q63_t)(blockSize - 1));
|
||||
|
||||
/* Compute square of mean */
|
||||
squareOfMean = (q31_t) ((q63_t)sum * sum / (q63_t)(blockSize * (blockSize - 1)));
|
||||
|
||||
/* mean of the squares minus the square of the mean. */
|
||||
/* Compute standard deviation and store the result to the destination */
|
||||
arm_sqrt_q15(__SSAT((meanOfSquares - squareOfMean) >> 15, 16u), pResult);
|
||||
|
||||
#endif /* #ifndef ARM_MATH_CM0_FAMILY */
|
||||
|
||||
|
||||
}
|
||||
|
||||
/**
|
||||
* @} end of STD group
|
||||
*/
|
||||
Loading…
Add table
Add a link
Reference in a new issue