502 lines
13 KiB
C
502 lines
13 KiB
C
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/* ----------------------------------------------------------------------
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* Project: CMSIS DSP Library
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* Title: arm_correlate_opt_q15.c
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* Description: Correlation of Q15 sequences
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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 groupFilters
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*/
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/**
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* @addtogroup Corr
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* @{
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*/
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/**
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* @brief Correlation of Q15 sequences.
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* @param[in] *pSrcA points to the first input sequence.
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* @param[in] srcALen length of the first input sequence.
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* @param[in] *pSrcB points to the second input sequence.
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* @param[in] srcBLen length of the second input sequence.
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* @param[out] *pDst points to the location where the output result is written. Length 2 * max(srcALen, srcBLen) - 1.
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* @param[in] *pScratch points to scratch buffer of size max(srcALen, srcBLen) + 2*min(srcALen, srcBLen) - 2.
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* @return none.
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*
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* \par Restrictions
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* If the silicon does not support unaligned memory access enable the macro UNALIGNED_SUPPORT_DISABLE
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* In this case input, output, scratch buffers should be aligned by 32-bit
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*
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* @details
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* <b>Scaling and Overflow Behavior:</b>
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*
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* \par
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* The function is implemented using a 64-bit internal accumulator.
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* Both inputs are in 1.15 format and multiplications yield a 2.30 result.
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* The 2.30 intermediate results are accumulated in a 64-bit accumulator in 34.30 format.
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* This approach provides 33 guard bits and there is no risk of overflow.
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* The 34.30 result is then truncated to 34.15 format by discarding the low 15 bits and then saturated to 1.15 format.
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*
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* \par
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* Refer to <code>arm_correlate_fast_q15()</code> for a faster but less precise version of this function for Cortex-M3 and Cortex-M4.
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*
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*
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*/
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void arm_correlate_opt_q15(
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q15_t * pSrcA,
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uint32_t srcALen,
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q15_t * pSrcB,
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uint32_t srcBLen,
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q15_t * pDst,
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q15_t * pScratch)
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{
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q15_t *pIn1; /* inputA pointer */
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q15_t *pIn2; /* inputB pointer */
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q63_t acc0, acc1, acc2, acc3; /* Accumulators */
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q15_t *py; /* Intermediate inputB pointer */
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q31_t x1, x2, x3; /* temporary variables for holding input1 and input2 values */
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uint32_t j, blkCnt, outBlockSize; /* loop counter */
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int32_t inc = 1; /* output pointer increment */
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uint32_t tapCnt;
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q31_t y1, y2;
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q15_t *pScr; /* Intermediate pointers */
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q15_t *pOut = pDst; /* output pointer */
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#ifdef UNALIGNED_SUPPORT_DISABLE
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q15_t a, b;
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#endif /* #ifndef UNALIGNED_SUPPORT_DISABLE */
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/* The algorithm implementation is based on the lengths of the inputs. */
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/* srcB is always made to slide across srcA. */
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/* So srcBLen is always considered as shorter or equal to srcALen */
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/* But CORR(x, y) is reverse of CORR(y, x) */
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/* So, when srcBLen > srcALen, output pointer is made to point to the end of the output buffer */
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/* and the destination pointer modifier, inc is set to -1 */
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/* If srcALen > srcBLen, zero pad has to be done to srcB to make the two inputs of same length */
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/* But to improve the performance,
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* we include zeroes in the output instead of zero padding either of the the inputs*/
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/* If srcALen > srcBLen,
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* (srcALen - srcBLen) zeroes has to included in the starting of the output buffer */
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/* If srcALen < srcBLen,
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* (srcALen - srcBLen) zeroes has to included in the ending of the output buffer */
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if (srcALen >= srcBLen)
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{
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/* Initialization of inputA pointer */
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pIn1 = (pSrcA);
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/* Initialization of inputB pointer */
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pIn2 = (pSrcB);
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/* Number of output samples is calculated */
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outBlockSize = (2U * srcALen) - 1U;
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/* When srcALen > srcBLen, zero padding is done to srcB
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* to make their lengths equal.
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* Instead, (outBlockSize - (srcALen + srcBLen - 1))
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* number of output samples are made zero */
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j = outBlockSize - (srcALen + (srcBLen - 1U));
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/* Updating the pointer position to non zero value */
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pOut += j;
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}
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else
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{
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/* Initialization of inputA pointer */
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pIn1 = (pSrcB);
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/* Initialization of inputB pointer */
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pIn2 = (pSrcA);
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/* srcBLen is always considered as shorter or equal to srcALen */
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j = srcBLen;
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srcBLen = srcALen;
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srcALen = j;
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/* CORR(x, y) = Reverse order(CORR(y, x)) */
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/* Hence set the destination pointer to point to the last output sample */
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pOut = pDst + ((srcALen + srcBLen) - 2U);
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/* Destination address modifier is set to -1 */
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inc = -1;
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}
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pScr = pScratch;
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/* Fill (srcBLen - 1U) zeros in scratch buffer */
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arm_fill_q15(0, pScr, (srcBLen - 1U));
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/* Update temporary scratch pointer */
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pScr += (srcBLen - 1U);
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#ifndef UNALIGNED_SUPPORT_DISABLE
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/* Copy (srcALen) samples in scratch buffer */
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arm_copy_q15(pIn1, pScr, srcALen);
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/* Update pointers */
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//pIn1 += srcALen;
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pScr += srcALen;
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#else
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/* Apply loop unrolling and do 4 Copies simultaneously. */
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j = srcALen >> 2U;
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/* First part of the processing with loop unrolling copies 4 data points at a time.
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** a second loop below copies for the remaining 1 to 3 samples. */
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while (j > 0U)
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{
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/* copy second buffer in reversal manner */
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*pScr++ = *pIn1++;
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*pScr++ = *pIn1++;
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*pScr++ = *pIn1++;
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*pScr++ = *pIn1++;
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/* Decrement the loop counter */
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j--;
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}
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/* If the count is not a multiple of 4, copy remaining samples here.
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** No loop unrolling is used. */
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j = srcALen % 0x4U;
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while (j > 0U)
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{
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/* copy second buffer in reversal manner for remaining samples */
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*pScr++ = *pIn1++;
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/* Decrement the loop counter */
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j--;
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}
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#endif /* #ifndef UNALIGNED_SUPPORT_DISABLE */
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#ifndef UNALIGNED_SUPPORT_DISABLE
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/* Fill (srcBLen - 1U) zeros at end of scratch buffer */
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arm_fill_q15(0, pScr, (srcBLen - 1U));
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/* Update pointer */
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pScr += (srcBLen - 1U);
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#else
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/* Apply loop unrolling and do 4 Copies simultaneously. */
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j = (srcBLen - 1U) >> 2U;
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/* First part of the processing with loop unrolling copies 4 data points at a time.
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** a second loop below copies for the remaining 1 to 3 samples. */
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while (j > 0U)
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{
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/* copy second buffer in reversal manner */
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*pScr++ = 0;
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*pScr++ = 0;
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*pScr++ = 0;
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*pScr++ = 0;
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/* Decrement the loop counter */
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j--;
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}
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/* If the count is not a multiple of 4, copy remaining samples here.
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** No loop unrolling is used. */
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j = (srcBLen - 1U) % 0x4U;
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while (j > 0U)
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{
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/* copy second buffer in reversal manner for remaining samples */
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*pScr++ = 0;
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/* Decrement the loop counter */
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j--;
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}
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#endif /* #ifndef UNALIGNED_SUPPORT_DISABLE */
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/* Temporary pointer for scratch2 */
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py = pIn2;
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/* Actual correlation process starts here */
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blkCnt = (srcALen + srcBLen - 1U) >> 2;
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while (blkCnt > 0)
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{
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/* Initialze temporary scratch pointer as scratch1 */
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pScr = pScratch;
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/* Clear Accumlators */
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acc0 = 0;
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acc1 = 0;
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acc2 = 0;
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acc3 = 0;
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/* Read four samples from scratch1 buffer */
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x1 = *__SIMD32(pScr)++;
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/* Read next four samples from scratch1 buffer */
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x2 = *__SIMD32(pScr)++;
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tapCnt = (srcBLen) >> 2U;
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while (tapCnt > 0U)
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{
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#ifndef UNALIGNED_SUPPORT_DISABLE
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/* Read four samples from smaller buffer */
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y1 = _SIMD32_OFFSET(pIn2);
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y2 = _SIMD32_OFFSET(pIn2 + 2U);
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acc0 = __SMLALD(x1, y1, acc0);
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acc2 = __SMLALD(x2, y1, acc2);
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#ifndef ARM_MATH_BIG_ENDIAN
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x3 = __PKHBT(x2, x1, 0);
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#else
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x3 = __PKHBT(x1, x2, 0);
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#endif
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acc1 = __SMLALDX(x3, y1, acc1);
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x1 = _SIMD32_OFFSET(pScr);
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acc0 = __SMLALD(x2, y2, acc0);
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acc2 = __SMLALD(x1, y2, acc2);
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#ifndef ARM_MATH_BIG_ENDIAN
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x3 = __PKHBT(x1, x2, 0);
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#else
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x3 = __PKHBT(x2, x1, 0);
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#endif
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acc3 = __SMLALDX(x3, y1, acc3);
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acc1 = __SMLALDX(x3, y2, acc1);
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x2 = _SIMD32_OFFSET(pScr + 2U);
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#ifndef ARM_MATH_BIG_ENDIAN
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x3 = __PKHBT(x2, x1, 0);
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#else
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x3 = __PKHBT(x1, x2, 0);
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#endif
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acc3 = __SMLALDX(x3, y2, acc3);
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#else
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/* Read four samples from smaller buffer */
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a = *pIn2;
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b = *(pIn2 + 1);
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#ifndef ARM_MATH_BIG_ENDIAN
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y1 = __PKHBT(a, b, 16);
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#else
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y1 = __PKHBT(b, a, 16);
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#endif
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a = *(pIn2 + 2);
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b = *(pIn2 + 3);
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#ifndef ARM_MATH_BIG_ENDIAN
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y2 = __PKHBT(a, b, 16);
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#else
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y2 = __PKHBT(b, a, 16);
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#endif
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acc0 = __SMLALD(x1, y1, acc0);
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acc2 = __SMLALD(x2, y1, acc2);
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#ifndef ARM_MATH_BIG_ENDIAN
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x3 = __PKHBT(x2, x1, 0);
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#else
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x3 = __PKHBT(x1, x2, 0);
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#endif
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acc1 = __SMLALDX(x3, y1, acc1);
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a = *pScr;
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b = *(pScr + 1);
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#ifndef ARM_MATH_BIG_ENDIAN
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x1 = __PKHBT(a, b, 16);
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#else
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x1 = __PKHBT(b, a, 16);
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#endif
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acc0 = __SMLALD(x2, y2, acc0);
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acc2 = __SMLALD(x1, y2, acc2);
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#ifndef ARM_MATH_BIG_ENDIAN
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x3 = __PKHBT(x1, x2, 0);
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#else
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x3 = __PKHBT(x2, x1, 0);
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#endif
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acc3 = __SMLALDX(x3, y1, acc3);
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acc1 = __SMLALDX(x3, y2, acc1);
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a = *(pScr + 2);
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b = *(pScr + 3);
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#ifndef ARM_MATH_BIG_ENDIAN
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x2 = __PKHBT(a, b, 16);
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#else
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x2 = __PKHBT(b, a, 16);
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#endif
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#ifndef ARM_MATH_BIG_ENDIAN
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x3 = __PKHBT(x2, x1, 0);
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#else
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x3 = __PKHBT(x1, x2, 0);
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#endif
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acc3 = __SMLALDX(x3, y2, acc3);
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#endif /* #ifndef UNALIGNED_SUPPORT_DISABLE */
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pIn2 += 4U;
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pScr += 4U;
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/* Decrement the loop counter */
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tapCnt--;
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}
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/* Update scratch pointer for remaining samples of smaller length sequence */
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pScr -= 4U;
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/* apply same above for remaining samples of smaller length sequence */
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tapCnt = (srcBLen) & 3U;
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while (tapCnt > 0U)
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{
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/* accumlate the results */
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acc0 += (*pScr++ * *pIn2);
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acc1 += (*pScr++ * *pIn2);
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acc2 += (*pScr++ * *pIn2);
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acc3 += (*pScr++ * *pIn2++);
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pScr -= 3U;
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/* Decrement the loop counter */
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tapCnt--;
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}
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blkCnt--;
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/* Store the results in the accumulators in the destination buffer. */
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*pOut = (__SSAT(acc0 >> 15U, 16));
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pOut += inc;
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*pOut = (__SSAT(acc1 >> 15U, 16));
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pOut += inc;
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*pOut = (__SSAT(acc2 >> 15U, 16));
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pOut += inc;
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*pOut = (__SSAT(acc3 >> 15U, 16));
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pOut += inc;
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/* Initialization of inputB pointer */
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pIn2 = py;
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pScratch += 4U;
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}
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blkCnt = (srcALen + srcBLen - 1U) & 0x3;
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/* Calculate correlation for remaining samples of Bigger length sequence */
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while (blkCnt > 0)
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||
|
{
|
||
|
/* Initialze temporary scratch pointer as scratch1 */
|
||
|
pScr = pScratch;
|
||
|
|
||
|
/* Clear Accumlators */
|
||
|
acc0 = 0;
|
||
|
|
||
|
tapCnt = (srcBLen) >> 1U;
|
||
|
|
||
|
while (tapCnt > 0U)
|
||
|
{
|
||
|
|
||
|
acc0 += (*pScr++ * *pIn2++);
|
||
|
acc0 += (*pScr++ * *pIn2++);
|
||
|
|
||
|
/* Decrement the loop counter */
|
||
|
tapCnt--;
|
||
|
}
|
||
|
|
||
|
tapCnt = (srcBLen) & 1U;
|
||
|
|
||
|
/* apply same above for remaining samples of smaller length sequence */
|
||
|
while (tapCnt > 0U)
|
||
|
{
|
||
|
|
||
|
/* accumlate the results */
|
||
|
acc0 += (*pScr++ * *pIn2++);
|
||
|
|
||
|
/* Decrement the loop counter */
|
||
|
tapCnt--;
|
||
|
}
|
||
|
|
||
|
blkCnt--;
|
||
|
|
||
|
/* Store the result in the accumulator in the destination buffer. */
|
||
|
*pOut = (q15_t) (__SSAT((acc0 >> 15), 16));
|
||
|
|
||
|
pOut += inc;
|
||
|
|
||
|
/* Initialization of inputB pointer */
|
||
|
pIn2 = py;
|
||
|
|
||
|
pScratch += 1U;
|
||
|
|
||
|
}
|
||
|
|
||
|
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* @} end of Corr group
|
||
|
*/
|