/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_mat_sub_q15.c
* Description: Q15 Matrix subtraction
*
* $Date: 18. March 2019
* $Revision: V1.6.0
*
* Target Processor: Cortex-M cores
* -------------------------------------------------------------------- */
/*
* Copyright (C) 2010-2019 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 MatrixSub
@{
*/
/**
@brief Q15 matrix subtraction.
@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 execution status
- \ref ARM_MATH_SUCCESS : Operation successful
- \ref ARM_MATH_SIZE_MISMATCH : Matrix size check failed
@par Scaling and Overflow Behavior
The function uses saturating arithmetic.
Results outside of the allowable Q15 range [0x8000 0x7FFF] are saturated.
*/
arm_status arm_mat_sub_q15(
const arm_matrix_instance_q15 * pSrcA,
const arm_matrix_instance_q15 * pSrcB,
arm_matrix_instance_q15 * pDst)
{
q15_t *pInA = pSrcA->pData; /* input data matrix pointer A */
q15_t *pInB = pSrcB->pData; /* input data matrix pointer B */
q15_t *pOut = pDst->pData; /* output data matrix pointer */
uint32_t numSamples; /* total number of elements in the matrix */
uint32_t blkCnt; /* loop counters */
arm_status status; /* status of matrix subtraction */
#ifdef ARM_MATH_MATRIX_CHECK
/* Check for matrix mismatch condition */
if ((pSrcA->numRows != pSrcB->numRows) ||
(pSrcA->numCols != pSrcB->numCols) ||
(pSrcA->numRows != pDst->numRows) ||
(pSrcA->numCols != pDst->numCols) )
{
/* Set status as ARM_MATH_SIZE_MISMATCH */
status = ARM_MATH_SIZE_MISMATCH;
}
else
#endif /* #ifdef ARM_MATH_MATRIX_CHECK */
{
/* Total number of samples in input matrix */
numSamples = (uint32_t) pSrcA->numRows * pSrcA->numCols;
#if defined (ARM_MATH_LOOPUNROLL)
/* Loop unrolling: Compute 4 outputs at a time */
blkCnt = numSamples >> 2U;
while (blkCnt > 0U)
{
/* C(m,n) = A(m,n) - B(m,n) */
/* Subtract, Saturate and store result in destination buffer. */
#if defined (ARM_MATH_DSP)
write_q15x2_ia (&pOut, __QSUB16(read_q15x2_ia ((q15_t **) &pInA), read_q15x2_ia ((q15_t **) &pInB)));
write_q15x2_ia (&pOut, __QSUB16(read_q15x2_ia ((q15_t **) &pInA), read_q15x2_ia ((q15_t **) &pInB)));
#else
*pOut++ = (q15_t) __SSAT(((q31_t) * pInA++ - *pInB++), 16);
*pOut++ = (q15_t) __SSAT(((q31_t) * pInA++ - *pInB++), 16);
*pOut++ = (q15_t) __SSAT(((q31_t) * pInA++ - *pInB++), 16);
*pOut++ = (q15_t) __SSAT(((q31_t) * pInA++ - *pInB++), 16);
#endif
/* Decrement loop counter */
blkCnt--;
}
/* Loop unrolling: Compute remaining outputs */
blkCnt = numSamples % 0x4U;
#else
/* Initialize blkCnt with number of samples */
blkCnt = numSamples;
#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
while (blkCnt > 0U)
{
/* C(m,n) = A(m,n) - B(m,n) */
/* Subtract and store result in destination buffer. */
#if defined (ARM_MATH_DSP)
*pOut++ = (q15_t) __QSUB16(*pInA++, *pInB++);
#else
*pOut++ = (q15_t) __SSAT(((q31_t) * pInA++ - *pInB++), 16);
#endif
/* Decrement loop counter */
blkCnt--;
}
/* Set status as ARM_MATH_SUCCESS */
status = ARM_MATH_SUCCESS;
}
/* Return to application */
return (status);
}
/**
@} end of MatrixSub group
*/
