/* ----------------------------------------------------------------------
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* Project: CMSIS DSP Library
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* Title: arm_conv_opt_q7.c
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* Description: Convolution of Q7 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 Conv
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* @{
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*/
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/**
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* @brief Convolution of Q7 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 srcALen+srcBLen-1.
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* @param[in] *pScratch1 points to scratch buffer(of type q15_t) of size max(srcALen, srcBLen) + 2*min(srcALen, srcBLen) - 2.
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* @param[in] *pScratch2 points to scratch buffer (of type q15_t) of size min(srcALen, srcBLen).
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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, scratch1 and scratch2 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 32-bit internal accumulator.
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* Both the inputs are represented in 1.7 format and multiplications yield a 2.14 result.
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* The 2.14 intermediate results are accumulated in a 32-bit accumulator in 18.14 format.
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* This approach provides 17 guard bits and there is no risk of overflow as long as <code>max(srcALen, srcBLen)<131072</code>.
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* The 18.14 result is then truncated to 18.7 format by discarding the low 7 bits and then saturated to 1.7 format.
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*
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*/
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void arm_conv_opt_q7(
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q7_t * pSrcA,
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uint32_t srcALen,
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q7_t * pSrcB,
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uint32_t srcBLen,
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q7_t * pDst,
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q15_t * pScratch1,
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q15_t * pScratch2)
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{
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q15_t *pScr2, *pScr1; /* Intermediate pointers for scratch pointers */
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q15_t x4; /* Temporary input variable */
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q7_t *pIn1, *pIn2; /* inputA and inputB pointer */
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uint32_t j, k, blkCnt, tapCnt; /* loop counter */
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q7_t *px; /* Temporary input1 pointer */
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q15_t *py; /* Temporary input2 pointer */
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q31_t acc0, acc1, acc2, acc3; /* Accumulator */
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q31_t x1, x2, x3, y1; /* Temporary input variables */
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q7_t *pOut = pDst; /* output pointer */
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q7_t out0, out1, out2, out3; /* temporary variables */
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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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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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}
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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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}
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/* pointer to take end of scratch2 buffer */
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pScr2 = pScratch2;
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/* points to smaller length sequence */
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px = pIn2 + srcBLen - 1;
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/* Apply loop unrolling and do 4 Copies simultaneously. */
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k = srcBLen >> 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 (k > 0U)
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{
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/* copy second buffer in reversal manner */
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x4 = (q15_t) * px--;
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*pScr2++ = x4;
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x4 = (q15_t) * px--;
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*pScr2++ = x4;
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x4 = (q15_t) * px--;
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*pScr2++ = x4;
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x4 = (q15_t) * px--;
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*pScr2++ = x4;
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/* Decrement the loop counter */
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k--;
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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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k = srcBLen % 0x4U;
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while (k > 0U)
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{
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/* copy second buffer in reversal manner for remaining samples */
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x4 = (q15_t) * px--;
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*pScr2++ = x4;
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/* Decrement the loop counter */
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k--;
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}
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/* Initialze temporary scratch pointer */
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pScr1 = pScratch1;
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/* Fill (srcBLen - 1U) zeros in scratch buffer */
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arm_fill_q15(0, pScr1, (srcBLen - 1U));
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/* Update temporary scratch pointer */
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pScr1 += (srcBLen - 1U);
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/* Copy (srcALen) samples in scratch buffer */
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/* Apply loop unrolling and do 4 Copies simultaneously. */
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k = 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 (k > 0U)
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{
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/* copy second buffer in reversal manner */
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x4 = (q15_t) * pIn1++;
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*pScr1++ = x4;
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x4 = (q15_t) * pIn1++;
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*pScr1++ = x4;
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x4 = (q15_t) * pIn1++;
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*pScr1++ = x4;
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x4 = (q15_t) * pIn1++;
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*pScr1++ = x4;
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/* Decrement the loop counter */
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k--;
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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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k = srcALen % 0x4U;
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while (k > 0U)
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{
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/* copy second buffer in reversal manner for remaining samples */
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x4 = (q15_t) * pIn1++;
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*pScr1++ = x4;
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/* Decrement the loop counter */
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k--;
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}
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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, pScr1, (srcBLen - 1U));
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/* Update pointer */
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pScr1 += (srcBLen - 1U);
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#else
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/* Apply loop unrolling and do 4 Copies simultaneously. */
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k = (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 (k > 0U)
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{
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/* copy second buffer in reversal manner */
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*pScr1++ = 0;
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*pScr1++ = 0;
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*pScr1++ = 0;
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*pScr1++ = 0;
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/* Decrement the loop counter */
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k--;
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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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k = (srcBLen - 1U) % 0x4U;
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while (k > 0U)
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{
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/* copy second buffer in reversal manner for remaining samples */
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*pScr1++ = 0;
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/* Decrement the loop counter */
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k--;
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}
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#endif
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/* Temporary pointer for scratch2 */
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py = pScratch2;
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/* Initialization of pIn2 pointer */
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pIn2 = (q7_t *) py;
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pScr2 = py;
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/* Actual convolution 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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pScr1 = pScratch1;
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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 two samples from scratch1 buffer */
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x1 = *__SIMD32(pScr1)++;
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/* Read next two samples from scratch1 buffer */
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x2 = *__SIMD32(pScr1)++;
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tapCnt = (srcBLen) >> 2U;
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while (tapCnt > 0U)
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{
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/* Read four samples from smaller buffer */
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y1 = _SIMD32_OFFSET(pScr2);
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/* multiply and accumlate */
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acc0 = __SMLAD(x1, y1, acc0);
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acc2 = __SMLAD(x2, y1, acc2);
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/* pack input data */
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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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/* multiply and accumlate */
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acc1 = __SMLADX(x3, y1, acc1);
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/* Read next two samples from scratch1 buffer */
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x1 = *__SIMD32(pScr1)++;
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/* pack input data */
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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 = __SMLADX(x3, y1, acc3);
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/* Read four samples from smaller buffer */
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y1 = _SIMD32_OFFSET(pScr2 + 2U);
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acc0 = __SMLAD(x2, y1, acc0);
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acc2 = __SMLAD(x1, y1, acc2);
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acc1 = __SMLADX(x3, y1, acc1);
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x2 = *__SIMD32(pScr1)++;
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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 = __SMLADX(x3, y1, acc3);
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pScr2 += 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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pScr1 -= 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 += (*pScr1++ * *pScr2);
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acc1 += (*pScr1++ * *pScr2);
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acc2 += (*pScr1++ * *pScr2);
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acc3 += (*pScr1++ * *pScr2++);
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pScr1 -= 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 result in the accumulator in the destination buffer. */
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out0 = (q7_t) (__SSAT(acc0 >> 7U, 8));
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out1 = (q7_t) (__SSAT(acc1 >> 7U, 8));
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out2 = (q7_t) (__SSAT(acc2 >> 7U, 8));
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out3 = (q7_t) (__SSAT(acc3 >> 7U, 8));
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*__SIMD32(pOut)++ = __PACKq7(out0, out1, out2, out3);
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/* Initialization of inputB pointer */
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pScr2 = py;
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pScratch1 += 4U;
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}
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blkCnt = (srcALen + srcBLen - 1U) & 0x3;
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/* Calculate convolution for remaining samples of Bigger length sequence */
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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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pScr1 = pScratch1;
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/* Clear Accumlators */
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acc0 = 0;
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tapCnt = (srcBLen) >> 1U;
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while (tapCnt > 0U)
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{
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acc0 += (*pScr1++ * *pScr2++);
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acc0 += (*pScr1++ * *pScr2++);
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/* Decrement the loop counter */
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tapCnt--;
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}
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tapCnt = (srcBLen) & 1U;
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/* apply same above for remaining samples of smaller length sequence */
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while (tapCnt > 0U)
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{
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/* accumlate the results */
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acc0 += (*pScr1++ * *pScr2++);
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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 result in the accumulator in the destination buffer. */
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*pOut++ = (q7_t) (__SSAT(acc0 >> 7U, 8));
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/* Initialization of inputB pointer */
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pScr2 = py;
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pScratch1 += 1U;
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}
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}
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/**
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* @} end of Conv group
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*/
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