/* ----------------------------------------------------------------------
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* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
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*
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* $Date: 19. March 2015
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* $Revision: V.1.4.5
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*
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* Project: CMSIS DSP Library
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* Title: arm_mat_sub_q31.c
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*
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* Description: Q31 matrix subtraction
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*
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* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* - Neither the name of ARM LIMITED nor the names of its contributors
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* may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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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 MatrixSub
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* @{
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*/
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/**
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* @brief Q31 matrix subtraction.
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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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* <b>Scaling and Overflow Behavior:</b>
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* \par
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* The function uses saturating arithmetic.
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* Results outside of the allowable Q31 range [0x80000000 0x7FFFFFFF] will be saturated.
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*/
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arm_status arm_mat_sub_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 *pIn1 = pSrcA->pData; /* input data matrix pointer A */
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q31_t *pIn2 = pSrcB->pData; /* input data matrix pointer B */
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q31_t *pOut = pDst->pData; /* output data matrix pointer */
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q31_t inA1, inB1; /* temporary variables */
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#ifndef ARM_MATH_CM0_FAMILY
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q31_t inA2, inB2; /* temporary variables */
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q31_t out1, out2; /* temporary variables */
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#endif // #ifndef ARM_MATH_CM0_FAMILY
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uint32_t numSamples; /* total number of elements in the matrix */
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uint32_t blkCnt; /* loop counters */
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arm_status status; /* status of matrix subtraction */
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#ifdef ARM_MATH_MATRIX_CHECK
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/* Check for matrix mismatch condition */
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if((pSrcA->numRows != pSrcB->numRows) ||
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(pSrcA->numCols != pSrcB->numCols) ||
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(pSrcA->numRows != pDst->numRows) || (pSrcA->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
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{
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/* Total number of samples in the input matrix */
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numSamples = (uint32_t) pSrcA->numRows * pSrcA->numCols;
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#ifndef ARM_MATH_CM0_FAMILY
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/* Run the below code for Cortex-M4 and Cortex-M3 */
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/* Loop Unrolling */
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blkCnt = numSamples >> 2u;
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/* First part of the processing with loop unrolling. Compute 4 outputs at a time.
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** a second loop below computes the remaining 1 to 3 samples. */
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while(blkCnt > 0u)
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{
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/* C(m,n) = A(m,n) - B(m,n) */
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/* Subtract, saturate and then store the results in the destination buffer. */
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/* Read values from source A */
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inA1 = pIn1[0];
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/* Read values from source B */
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inB1 = pIn2[0];
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/* Read values from source A */
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inA2 = pIn1[1];
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/* Subtract and saturate */
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out1 = __QSUB(inA1, inB1);
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/* Read values from source B */
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inB2 = pIn2[1];
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/* Read values from source A */
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inA1 = pIn1[2];
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/* Subtract and saturate */
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out2 = __QSUB(inA2, inB2);
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/* Read values from source B */
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inB1 = pIn2[2];
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/* Store result in destination */
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pOut[0] = out1;
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pOut[1] = out2;
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/* Read values from source A */
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inA2 = pIn1[3];
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/* Read values from source B */
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inB2 = pIn2[3];
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/* Subtract and saturate */
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out1 = __QSUB(inA1, inB1);
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/* Subtract and saturate */
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out2 = __QSUB(inA2, inB2);
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/* Store result in destination */
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pOut[2] = out1;
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pOut[3] = out2;
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/* update pointers to process next samples */
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pIn1 += 4u;
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pIn2 += 4u;
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pOut += 4u;
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/* Decrement the loop counter */
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blkCnt--;
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}
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/* If the numSamples is not a multiple of 4, compute any remaining output samples here.
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** No loop unrolling is used. */
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blkCnt = numSamples % 0x4u;
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#else
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/* Run the below code for Cortex-M0 */
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/* Initialize blkCnt with number of samples */
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blkCnt = numSamples;
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#endif /* #ifndef ARM_MATH_CM0_FAMILY */
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while(blkCnt > 0u)
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{
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/* C(m,n) = A(m,n) - B(m,n) */
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/* Subtract, saturate and then store the results in the destination buffer. */
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inA1 = *pIn1++;
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inB1 = *pIn2++;
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inA1 = __QSUB(inA1, inB1);
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*pOut++ = inA1;
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/* Decrement the loop counter */
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blkCnt--;
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}
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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 MatrixSub group
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*/
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