167 lines
4.3 KiB
C
167 lines
4.3 KiB
C
/* ----------------------------------------------------------------------
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* Project: CMSIS DSP Library
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* Title: arm_abs_q15.c
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* Description: Q15 vector absolute value
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*
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* $Date: 27. January 2017
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* $Revision: V.1.5.1
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*
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* Target Processor: Cortex-M cores
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* -------------------------------------------------------------------- */
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/*
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* Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the License); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an AS IS BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "arm_math.h"
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/**
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* @ingroup groupMath
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*/
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/**
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* @addtogroup BasicAbs
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* @{
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*/
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/**
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* @brief Q15 vector absolute value.
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* @param[in] *pSrc points to the input buffer
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* @param[out] *pDst points to the output buffer
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* @param[in] blockSize number of samples in each vector
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* @return none.
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*
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* <b>Scaling and Overflow Behavior:</b>
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* \par
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* The function uses saturating arithmetic.
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* The Q15 value -1 (0x8000) will be saturated to the maximum allowable positive value 0x7FFF.
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*/
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void arm_abs_q15(
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q15_t * pSrc,
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q15_t * pDst,
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uint32_t blockSize)
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{
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uint32_t blkCnt; /* loop counter */
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#if defined (ARM_MATH_DSP)
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__SIMD32_TYPE *simd;
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/* Run the below code for Cortex-M4 and Cortex-M3 */
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q15_t in1; /* Input value1 */
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q15_t in2; /* Input value2 */
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/*loop Unrolling */
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blkCnt = blockSize >> 2u;
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/* First part of the processing with loop unrolling. Compute 4 outputs at a time.
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** a second loop below computes the remaining 1 to 3 samples. */
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simd = __SIMD32_CONST(pDst);
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while (blkCnt > 0u)
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{
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/* C = |A| */
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/* Read two inputs */
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in1 = *pSrc++;
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in2 = *pSrc++;
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/* Store the Absolute result in the destination buffer by packing the two values, in a single cycle */
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#ifndef ARM_MATH_BIG_ENDIAN
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*simd++ =
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__PKHBT(((in1 > 0) ? in1 : (q15_t)__QSUB16(0, in1)),
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((in2 > 0) ? in2 : (q15_t)__QSUB16(0, in2)), 16);
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#else
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*simd++ =
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__PKHBT(((in2 > 0) ? in2 : (q15_t)__QSUB16(0, in2)),
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((in1 > 0) ? in1 : (q15_t)__QSUB16(0, in1)), 16);
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#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
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in1 = *pSrc++;
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in2 = *pSrc++;
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#ifndef ARM_MATH_BIG_ENDIAN
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*simd++ =
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__PKHBT(((in1 > 0) ? in1 : (q15_t)__QSUB16(0, in1)),
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((in2 > 0) ? in2 : (q15_t)__QSUB16(0, in2)), 16);
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#else
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*simd++ =
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__PKHBT(((in2 > 0) ? in2 : (q15_t)__QSUB16(0, in2)),
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((in1 > 0) ? in1 : (q15_t)__QSUB16(0, in1)), 16);
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#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
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/* Decrement the loop counter */
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blkCnt--;
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}
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pDst = (q15_t *)simd;
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/* If the blockSize is not a multiple of 4, compute any remaining output samples here.
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** No loop unrolling is used. */
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blkCnt = blockSize % 0x4u;
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while (blkCnt > 0u)
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{
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/* C = |A| */
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/* Read the input */
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in1 = *pSrc++;
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/* Calculate absolute value of input and then store the result in the destination buffer. */
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*pDst++ = (in1 > 0) ? in1 : (q15_t)__QSUB16(0, in1);
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/* Decrement the loop counter */
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blkCnt--;
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}
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#else
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/* Run the below code for Cortex-M0 */
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q15_t in; /* Temporary input variable */
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/* Initialize blkCnt with number of samples */
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blkCnt = blockSize;
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while (blkCnt > 0u)
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{
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/* C = |A| */
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/* Read the input */
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in = *pSrc++;
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/* Calculate absolute value of input and then store the result in the destination buffer. */
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*pDst++ = (in > 0) ? in : ((in == (q15_t) 0x8000) ? 0x7fff : -in);
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/* Decrement the loop counter */
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blkCnt--;
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}
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#endif /* #if defined (ARM_MATH_DSP) */
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}
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/**
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* @} end of BasicAbs group
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*/
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