/* ----------------------------------------------------------------------
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* Project: CMSIS DSP Library
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* Title: arm_mat_mult_fast_q31.c
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* Description: Q31 matrix multiplication (fast variant)
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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 groupMatrix
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*/
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/**
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* @addtogroup MatrixMult
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* @{
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*/
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/**
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* @brief Q31 matrix multiplication (fast variant) for Cortex-M3 and Cortex-M4
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* @param[in] *pSrcA points to the first input matrix structure
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* @param[in] *pSrcB points to the second input matrix structure
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* @param[out] *pDst points to output matrix structure
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* @return The function returns either
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* <code>ARM_MATH_SIZE_MISMATCH</code> or <code>ARM_MATH_SUCCESS</code> based on the outcome of size checking.
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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 difference between the function arm_mat_mult_q31() and this fast variant is that
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* the fast variant use a 32-bit rather than a 64-bit accumulator.
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* The result of each 1.31 x 1.31 multiplication is truncated to
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* 2.30 format. These intermediate results are accumulated in a 32-bit register in 2.30
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* format. Finally, the accumulator is saturated and converted to a 1.31 result.
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*
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* \par
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* The fast version has the same overflow behavior as the standard version but provides
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* less precision since it discards the low 32 bits of each multiplication result.
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* In order to avoid overflows completely the input signals must be scaled down.
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* Scale down one of the input matrices by log2(numColsA) bits to
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* avoid overflows, as a total of numColsA additions are computed internally for each
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* output element.
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*
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* \par
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* See <code>arm_mat_mult_q31()</code> for a slower implementation of this function
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* which uses 64-bit accumulation to provide higher precision.
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*/
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arm_status arm_mat_mult_fast_q31(
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const arm_matrix_instance_q31 * pSrcA,
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const arm_matrix_instance_q31 * pSrcB,
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arm_matrix_instance_q31 * pDst)
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{
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q31_t *pInA = pSrcA->pData; /* input data matrix pointer A */
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q31_t *pInB = pSrcB->pData; /* input data matrix pointer B */
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q31_t *px; /* Temporary output data matrix pointer */
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q31_t sum; /* Accumulator */
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uint16_t numRowsA = pSrcA->numRows; /* number of rows of input matrix A */
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uint16_t numColsB = pSrcB->numCols; /* number of columns of input matrix B */
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uint16_t numColsA = pSrcA->numCols; /* number of columns of input matrix A */
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uint32_t col, i = 0U, j, row = numRowsA, colCnt; /* loop counters */
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arm_status status; /* status of matrix multiplication */
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q31_t inA1, inB1;
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#if defined (ARM_MATH_DSP)
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q31_t sum2, sum3, sum4;
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q31_t inA2, inB2;
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q31_t *pInA2;
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q31_t *px2;
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#endif
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#ifdef ARM_MATH_MATRIX_CHECK
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/* Check for matrix mismatch condition */
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if ((pSrcA->numCols != pSrcB->numRows) ||
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(pSrcA->numRows != pDst->numRows) || (pSrcB->numCols != pDst->numCols))
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{
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/* Set status as ARM_MATH_SIZE_MISMATCH */
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status = ARM_MATH_SIZE_MISMATCH;
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}
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else
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#endif /* #ifdef ARM_MATH_MATRIX_CHECK */
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{
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px = pDst->pData;
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#if defined (ARM_MATH_DSP)
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row = row >> 1;
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px2 = px + numColsB;
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#endif
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/* The following loop performs the dot-product of each row in pSrcA with each column in pSrcB */
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/* row loop */
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while (row > 0U)
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{
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/* For every row wise process, the column loop counter is to be initiated */
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col = numColsB;
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/* For every row wise process, the pIn2 pointer is set
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** to the starting address of the pSrcB data */
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pInB = pSrcB->pData;
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j = 0U;
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#if defined (ARM_MATH_DSP)
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col = col >> 1;
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#endif
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/* column loop */
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while (col > 0U)
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{
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/* Set the variable sum, that acts as accumulator, to zero */
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sum = 0;
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/* Initiate data pointers */
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pInA = pSrcA->pData + i;
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pInB = pSrcB->pData + j;
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#if defined (ARM_MATH_DSP)
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sum2 = 0;
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sum3 = 0;
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sum4 = 0;
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pInA2 = pInA + numColsA;
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colCnt = numColsA;
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#else
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colCnt = numColsA >> 2;
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#endif
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/* matrix multiplication */
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while (colCnt > 0U)
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{
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#if defined (ARM_MATH_DSP)
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inA1 = *pInA++;
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inB1 = pInB[0];
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inA2 = *pInA2++;
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inB2 = pInB[1];
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pInB += numColsB;
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sum = __SMMLA(inA1, inB1, sum);
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sum2 = __SMMLA(inA1, inB2, sum2);
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sum3 = __SMMLA(inA2, inB1, sum3);
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sum4 = __SMMLA(inA2, inB2, sum4);
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#else
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/* c(m,n) = a(1,1)*b(1,1) + a(1,2) * b(2,1) + .... + a(m,p)*b(p,n) */
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/* Perform the multiply-accumulates */
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inB1 = *pInB;
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pInB += numColsB;
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inA1 = pInA[0];
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sum = __SMMLA(inA1, inB1, sum);
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inB1 = *pInB;
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pInB += numColsB;
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inA1 = pInA[1];
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sum = __SMMLA(inA1, inB1, sum);
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inB1 = *pInB;
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pInB += numColsB;
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inA1 = pInA[2];
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sum = __SMMLA(inA1, inB1, sum);
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inB1 = *pInB;
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pInB += numColsB;
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inA1 = pInA[3];
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sum = __SMMLA(inA1, inB1, sum);
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pInA += 4U;
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#endif
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/* Decrement the loop counter */
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colCnt--;
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}
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#ifdef ARM_MATH_CM0_FAMILY
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/* If the columns of pSrcA is not a multiple of 4, compute any remaining output samples here. */
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colCnt = numColsA % 0x4U;
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while (colCnt > 0U)
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{
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sum = __SMMLA(*pInA++, *pInB, sum);
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pInB += numColsB;
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colCnt--;
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}
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j++;
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#endif
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/* Convert the result from 2.30 to 1.31 format and store in destination buffer */
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*px++ = sum << 1;
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#if defined (ARM_MATH_DSP)
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*px++ = sum2 << 1;
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*px2++ = sum3 << 1;
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*px2++ = sum4 << 1;
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j += 2;
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#endif
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/* Decrement the column loop counter */
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col--;
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}
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i = i + numColsA;
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#if defined (ARM_MATH_DSP)
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i = i + numColsA;
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px = px2 + (numColsB & 1U);
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px2 = px + numColsB;
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#endif
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/* Decrement the row loop counter */
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row--;
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}
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/* Compute any remaining odd row/column below */
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#if defined (ARM_MATH_DSP)
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/* Compute remaining output column */
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if (numColsB & 1U) {
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/* Avoid redundant computation of last element */
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row = numRowsA & (~0x1);
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/* Point to remaining unfilled column in output matrix */
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px = pDst->pData+numColsB-1;
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pInA = pSrcA->pData;
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/* row loop */
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while (row > 0)
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{
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/* point to last column in matrix B */
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pInB = pSrcB->pData + numColsB-1;
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/* Set the variable sum, that acts as accumulator, to zero */
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sum = 0;
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/* Compute 4 columns at once */
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colCnt = numColsA >> 2;
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/* matrix multiplication */
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while (colCnt > 0U)
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{
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inA1 = *pInA++;
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inA2 = *pInA++;
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inB1 = *pInB;
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pInB += numColsB;
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inB2 = *pInB;
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pInB += numColsB;
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sum = __SMMLA(inA1, inB1, sum);
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sum = __SMMLA(inA2, inB2, sum);
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inA1 = *pInA++;
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inA2 = *pInA++;
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inB1 = *pInB;
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pInB += numColsB;
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inB2 = *pInB;
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pInB += numColsB;
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sum = __SMMLA(inA1, inB1, sum);
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sum = __SMMLA(inA2, inB2, sum);
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/* Decrement the loop counter */
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colCnt--;
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}
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colCnt = numColsA & 3U;
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while (colCnt > 0U) {
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sum = __SMMLA(*pInA++, *pInB, sum);
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pInB += numColsB;
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colCnt--;
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}
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/* Convert the result from 2.30 to 1.31 format and store in destination buffer */
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*px = sum << 1;
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px += numColsB;
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/* Decrement the row loop counter */
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row--;
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}
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}
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/* Compute remaining output row */
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if (numRowsA & 1U) {
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/* point to last row in output matrix */
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px = pDst->pData+(numColsB)*(numRowsA-1);
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col = numColsB;
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i = 0U;
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/* col loop */
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while (col > 0)
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{
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/* point to last row in matrix A */
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pInA = pSrcA->pData + (numRowsA-1)*numColsA;
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pInB = pSrcB->pData + i;
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/* Set the variable sum, that acts as accumulator, to zero */
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sum = 0;
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/* Compute 4 columns at once */
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colCnt = numColsA >> 2;
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/* matrix multiplication */
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while (colCnt > 0U)
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{
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inA1 = *pInA++;
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inA2 = *pInA++;
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inB1 = *pInB;
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pInB += numColsB;
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inB2 = *pInB;
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pInB += numColsB;
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sum = __SMMLA(inA1, inB1, sum);
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sum = __SMMLA(inA2, inB2, sum);
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inA1 = *pInA++;
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inA2 = *pInA++;
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inB1 = *pInB;
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pInB += numColsB;
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inB2 = *pInB;
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pInB += numColsB;
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sum = __SMMLA(inA1, inB1, sum);
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sum = __SMMLA(inA2, inB2, sum);
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/* Decrement the loop counter */
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colCnt--;
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}
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colCnt = numColsA & 3U;
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while (colCnt > 0U) {
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sum = __SMMLA(*pInA++, *pInB, sum);
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pInB += numColsB;
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colCnt--;
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}
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/* Saturate and store the result in the destination buffer */
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*px++ = sum << 1;
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i++;
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/* Decrement the col loop counter */
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col--;
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}
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}
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#endif /* #if defined (ARM_MATH_DSP) */
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/* set status as ARM_MATH_SUCCESS */
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status = ARM_MATH_SUCCESS;
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}
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/* Return to application */
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return (status);
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}
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/**
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* @} end of MatrixMult group
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*/
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