/* ----------------------------------------------------------------------
* Copyright (C) 2010 ARM Limited. All rights reserved.
*
* $Date: 15. February 2012
* $Revision: V1.1.0
*
* Project: CMSIS DSP Library
* Title: arm_mat_sub_q31.c
*
* Description: Q31 matrix subtraction
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Version 1.1.0 2012/02/15
* Updated with more optimizations, bug fixes and minor API changes.
*
* 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.
*
* Version 0.0.5 2010/04/26
* incorporated review comments and updated with latest CMSIS layer
*
* Version 0.0.3 2010/03/10
* Initial version
* -------------------------------------------------------------------- */
#include "arm_math.h"
/**
* @ingroup groupMatrix
*/
/**
* @addtogroup MatrixSub
* @{
*/
/**
* @brief Q31 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 The function returns either
* <code>ARM_MATH_SIZE_MISMATCH</code> or <code>ARM_MATH_SUCCESS</code> based on the outcome of size checking.
*
* <b>Scaling and Overflow Behavior:</b>
* \par
* The function uses saturating arithmetic.
* Results outside of the allowable Q31 range [0x80000000 0x7FFFFFFF] will be saturated.
*/
arm_status arm_mat_sub_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 *pOut = pDst->pData; /* output data matrix pointer */
q31_t inA1, inB1; /* temporary variables */
#ifndef ARM_MATH_CM0
q31_t inA2, inB2; /* temporary variables */
q31_t out1, out2; /* temporary variables */
#endif // #ifndef ARM_MATH_CM0
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
{
/* Total number of samples in the input matrix */
numSamples = (uint32_t) pSrcA->numRows * pSrcA->numCols;
#ifndef ARM_MATH_CM0
/* Run the below code for Cortex-M4 and Cortex-M3 */
/* Loop Unrolling */
blkCnt = numSamples >> 2u;
/* First part of the processing with loop unrolling. Compute 4 outputs at a time.
** a second loop below computes the remaining 1 to 3 samples. */
while(blkCnt > 0u)
{
/* C(m,n) = A(m,n) - B(m,n) */
/* Subtract, saturate and then store the results in the destination buffer. */
/* Read values from source A */
inA1 = pIn1[0];
/* Read values from source B */
inB1 = pIn2[0];
/* Read values from source A */
inA2 = pIn1[1];
/* Subtract and saturate */
out1 = __QSUB(inA1, inB1);
/* Read values from source B */
inB2 = pIn2[1];
/* Read values from source A */
inA1 = pIn1[2];
/* Subtract and saturate */
out2 = __QSUB(inA2, inB2);
/* Read values from source B */
inB1 = pIn2[2];
/* Store result in destination */
pOut[0] = out1;
pOut[1] = out2;
/* Read values from source A */
inA2 = pIn1[3];
/* Read values from source B */
inB2 = pIn2[3];
/* Subtract and saturate */
out1 = __QSUB(inA1, inB1);
/* Subtract and saturate */
out2 = __QSUB(inA2, inB2);
/* Store result in destination */
pOut[2] = out1;
pOut[3] = out2;
/* update pointers to process next samples */
pIn1 += 4u;
pIn2 += 4u;
pOut += 4u;
/* Decrement the loop counter */
blkCnt--;
}
/* If the numSamples is not a multiple of 4, compute any remaining output samples here.
** No loop unrolling is used. */
blkCnt = numSamples % 0x4u;
#else
/* Run the below code for Cortex-M0 */
/* Initialize blkCnt with number of samples */
blkCnt = numSamples;
#endif /* #ifndef ARM_MATH_CM0 */
while(blkCnt > 0u)
{
/* C(m,n) = A(m,n) - B(m,n) */
/* Subtract, saturate and then store the results in the destination buffer. */
inA1 = *pIn1++;
inB1 = *pIn2++;
inA1 = __QSUB(inA1, inB1);
*pOut++ = inA1;
/* Decrement the loop counter */
blkCnt--;
}
/* Set status as ARM_MATH_SUCCESS */
status = ARM_MATH_SUCCESS;
}
/* Return to application */
return (status);
}
/**
* @} end of MatrixSub group
*/