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