arm_mat_mult_fast_q31.c
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r41 | /* ---------------------------------------------------------------------- | ||
* Copyright (C) 2010 ARM Limited. All rights reserved. | ||||
* | ||||
* $Date: 15. July 2011 | ||||
* $Revision: V1.0.10 | ||||
* | ||||
* Project: CMSIS DSP Library | ||||
* Title: arm_mat_mult_fast_q31.c | ||||
* | ||||
* Description: Q31 matrix multiplication (fast variant). | ||||
* | ||||
* Target Processor: Cortex-M4/Cortex-M3 | ||||
* | ||||
* Version 1.0.10 2011/7/15 | ||||
* Big Endian support added and Merged M0 and M3/M4 Source code. | ||||
* | ||||
* Version 1.0.3 2010/11/29 | ||||
* Re-organized the CMSIS folders and updated documentation. | ||||
* | ||||
* Version 1.0.2 2010/11/11 | ||||
* Documentation updated. | ||||
* | ||||
* Version 1.0.1 2010/10/05 | ||||
* Production release and review comments incorporated. | ||||
* | ||||
* Version 1.0.0 2010/09/20 | ||||
* Production release and review comments incorporated. | ||||
* -------------------------------------------------------------------- */ | ||||
#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 *pIn1 = pSrcA->pData; /* input data matrix pointer A */ | ||||
q31_t *pIn2 = pSrcB->pData; /* input data matrix pointer B */ | ||||
q31_t *pInA = pSrcA->pData; /* input data matrix pointer A */ | ||||
// q31_t *pSrcB = pSrcB->pData; /* input data matrix pointer B */ | ||||
q31_t *pOut = pDst->pData; /* output data matrix pointer */ | ||||
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 */ | ||||
uint16_t col, i = 0u, j, row = numRowsA, colCnt; /* loop counters */ | ||||
arm_status status; /* status of matrix multiplication */ | ||||
#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 */ | ||||
{ | ||||
/* The following loop performs the dot-product of each row in pSrcA with each column in pSrcB */ | ||||
/* row loop */ | ||||
do | ||||
{ | ||||
/* Output pointer is set to starting address of the row being processed */ | ||||
px = pOut + i; | ||||
/* 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 */ | ||||
pIn2 = pSrcB->pData; | ||||
j = 0u; | ||||
/* column loop */ | ||||
do | ||||
{ | ||||
/* Set the variable sum, that acts as accumulator, to zero */ | ||||
sum = 0; | ||||
/* Initiate the pointer pIn1 to point to the starting address of pInA */ | ||||
pIn1 = pInA; | ||||
/* Apply loop unrolling and compute 4 MACs simultaneously. */ | ||||
colCnt = numColsA >> 2; | ||||
/* matrix multiplication */ | ||||
while(colCnt > 0u) | ||||
{ | ||||
/* 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 */ | ||||
sum = (q31_t) ((((q63_t) sum << 32) + | ||||
((q63_t) * pIn1++ * (*pIn2))) >> 32); | ||||
pIn2 += numColsB; | ||||
sum = (q31_t) ((((q63_t) sum << 32) + | ||||
((q63_t) * pIn1++ * (*pIn2))) >> 32); | ||||
pIn2 += numColsB; | ||||
sum = (q31_t) ((((q63_t) sum << 32) + | ||||
((q63_t) * pIn1++ * (*pIn2))) >> 32); | ||||
pIn2 += numColsB; | ||||
sum = (q31_t) ((((q63_t) sum << 32) + | ||||
((q63_t) * pIn1++ * (*pIn2))) >> 32); | ||||
pIn2 += numColsB; | ||||
/* Decrement the loop counter */ | ||||
colCnt--; | ||||
} | ||||
/* If the columns of pSrcA is not a multiple of 4, compute any remaining output samples here. | ||||
** No loop unrolling is used. */ | ||||
colCnt = numColsA % 0x4u; | ||||
while(colCnt > 0u) | ||||
{ | ||||
/* 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 */ | ||||
sum = (q31_t) ((((q63_t) sum << 32) + | ||||
((q63_t) * pIn1++ * (*pIn2))) >> 32); | ||||
pIn2 += numColsB; | ||||
/* Decrement the loop counter */ | ||||
colCnt--; | ||||
} | ||||
/* Convert the result from 2.30 to 1.31 format and store in destination buffer */ | ||||
*px++ = sum << 1; | ||||
/* Update the pointer pIn2 to point to the starting address of the next column */ | ||||
j++; | ||||
pIn2 = pSrcB->pData + j; | ||||
/* Decrement the column loop counter */ | ||||
col--; | ||||
} while(col > 0u); | ||||
/* Update the pointer pInA to point to the starting address of the next row */ | ||||
i = i + numColsB; | ||||
pInA = pInA + numColsA; | ||||
/* Decrement the row loop counter */ | ||||
row--; | ||||
} while(row > 0u); | ||||
/* set status as ARM_MATH_SUCCESS */ | ||||
status = ARM_MATH_SUCCESS; | ||||
} | ||||
/* Return to application */ | ||||
return (status); | ||||
} | ||||
/** | ||||
* @} end of MatrixMult group | ||||
*/ | ||||