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/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_abs_q15.c
* Description: Q15 vector absolute value
*
* $Date: 27. January 2017
* $Revision: V.1.5.1
*
* Target Processor: Cortex-M cores
* -------------------------------------------------------------------- */
/*
* Copyright (C) 2010-2017 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 groupMath
*/
/**
* @addtogroup BasicAbs
* @{
*/
/**
* @brief Q15 vector absolute value.
* @param[in] *pSrc points to the input buffer
* @param[out] *pDst points to the output buffer
* @param[in] blockSize number of samples in each vector
* @return none.
*
* <b>Scaling and Overflow Behavior:</b>
* \par
* The function uses saturating arithmetic.
* The Q15 value -1 (0x8000) will be saturated to the maximum allowable positive value 0x7FFF.
*/
void arm_abs_q15(
q15_t * pSrc,
q15_t * pDst,
uint32_t blockSize)
{
uint32_t blkCnt; /* loop counter */
#if defined (ARM_MATH_DSP)
__SIMD32_TYPE *simd;
/* Run the below code for Cortex-M4 and Cortex-M3 */
q15_t in1; /* Input value1 */
q15_t in2; /* Input value2 */
/*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. */
simd = __SIMD32_CONST(pDst);
while (blkCnt > 0U)
{
/* C = |A| */
/* Read two inputs */
in1 = *pSrc++;
in2 = *pSrc++;
/* Store the Absolute result in the destination buffer by packing the two values, in a single cycle */
#ifndef ARM_MATH_BIG_ENDIAN
*simd++ =
__PKHBT(((in1 > 0) ? in1 : (q15_t)__QSUB16(0, in1)),
((in2 > 0) ? in2 : (q15_t)__QSUB16(0, in2)), 16);
#else
*simd++ =
__PKHBT(((in2 > 0) ? in2 : (q15_t)__QSUB16(0, in2)),
((in1 > 0) ? in1 : (q15_t)__QSUB16(0, in1)), 16);
#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
in1 = *pSrc++;
in2 = *pSrc++;
#ifndef ARM_MATH_BIG_ENDIAN
*simd++ =
__PKHBT(((in1 > 0) ? in1 : (q15_t)__QSUB16(0, in1)),
((in2 > 0) ? in2 : (q15_t)__QSUB16(0, in2)), 16);
#else
*simd++ =
__PKHBT(((in2 > 0) ? in2 : (q15_t)__QSUB16(0, in2)),
((in1 > 0) ? in1 : (q15_t)__QSUB16(0, in1)), 16);
#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
/* Decrement the loop counter */
blkCnt--;
}
pDst = (q15_t *)simd;
/* 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| */
/* Read the input */
in1 = *pSrc++;
/* Calculate absolute value of input and then store the result in the destination buffer. */
*pDst++ = (in1 > 0) ? in1 : (q15_t)__QSUB16(0, in1);
/* Decrement the loop counter */
blkCnt--;
}
#else
/* Run the below code for Cortex-M0 */
q15_t in; /* Temporary input variable */
/* Initialize blkCnt with number of samples */
blkCnt = blockSize;
while (blkCnt > 0U)
{
/* C = |A| */
/* Read the input */
in = *pSrc++;
/* Calculate absolute value of input and then store the result in the destination buffer. */
*pDst++ = (in > 0) ? in : ((in == (q15_t) 0x8000) ? 0x7fff : -in);
/* Decrement the loop counter */
blkCnt--;
}
#endif /* #if defined (ARM_MATH_DSP) */
}
/**
* @} end of BasicAbs group
*/
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