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# arm_mat_sub_q31.c

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    00001 /* ----------------------------------------------------------------------
    00002 * Copyright (C) 2010 ARM Limited. All rights reserved.
    00003 *
    00004 * $Date:        29. November 2010
    00005 * $Revision:    V1.0.3
    00006 *
    00007 * Project:      CMSIS DSP Library
    00008 * Title:        arm_mat_sub_q31.c
    00009 *
    00010 * Description:  Q31 matrix subtraction
    00011 *
    00012 * Target Processor: Cortex-M4/Cortex-M3
    00013 *
    00014 * Version 1.0.3 2010/11/29
    00015 *    Re-organized the CMSIS folders and updated documentation.
    00016 *
    00017 * Version 1.0.2 2010/11/11
    00018 *    Documentation updated.
    00019 *
    00020 * Version 1.0.1 2010/10/05
    00021 *    Production release and review comments incorporated.
    00022 *
    00023 * Version 1.0.0 2010/09/20
    00024 *    Production release and review comments incorporated.
    00025 *
    00026 * Version 0.0.5  2010/04/26
    00027 *    incorporated review comments and updated with latest CMSIS layer
    00028 *
    00029 * Version 0.0.3  2010/03/10
    00030 *    Initial version
    00031 * -------------------------------------------------------------------- */
    00032
    00033 #include "arm_math.h"
    00034
    00059 arm_status arm_mat_sub_q31(
    00060   const arm_matrix_instance_q31 * pSrcA,
    00061   const arm_matrix_instance_q31 * pSrcB,
    00062   arm_matrix_instance_q31 * pDst)
    00063 {
    00064   q31_t *pIn1 = pSrcA->pData;                    /* input data matrix pointer A */
    00065   q31_t *pIn2 = pSrcB->pData;                    /* input data matrix pointer B */
    00066   q31_t *pOut = pDst->pData;                     /* output data matrix pointer */
    00067   uint32_t numSamples;                           /* total number of elements in the matrix  */
    00068   uint32_t blkCnt;                               /* loop counters */
    00069   arm_status status;                             /* status of matrix subtraction */
    00070
    00071
    00072 #ifdef ARM_MATH_MATRIX_CHECK
    00073   /* Check for matrix mismatch condition  */
    00074   if((pSrcA->numRows != pSrcB->numRows) ||
    00075      (pSrcA->numCols != pSrcB->numCols) ||
    00076      (pSrcA->numRows != pDst->numRows) || (pSrcA->numCols != pDst->numCols))
    00077   {
    00078     /* Set status as ARM_MATH_SIZE_MISMATCH */
    00079     status = ARM_MATH_SIZE_MISMATCH;
    00080   }
    00081   else
    00082 #endif
    00083   {
    00084     /* Total number of samples in the input matrix */
    00085     numSamples = (uint32_t) pSrcA->numRows * pSrcA->numCols;
    00086
    00087     /* Loop Unrolling */
    00088     blkCnt = numSamples >> 2u;
    00089
    00090     /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
    00091      ** a second loop below computes the remaining 1 to 3 samples. */
    00092     while(blkCnt > 0u)
    00093     {
    00094       /* C(m,n) = A(m,n) - B(m,n) */
    00095       /* Subtract, saturate and then store the results in the destination buffer. */
    00096       *pOut++ = __QSUB(*pIn1++, *pIn2++);
    00097       *pOut++ = __QSUB(*pIn1++, *pIn2++);
    00098       *pOut++ = __QSUB(*pIn1++, *pIn2++);
    00099       *pOut++ = __QSUB(*pIn1++, *pIn2++);
    00100
    00101       /* Decrement the loop counter */
    00102       blkCnt--;
    00103     }
    00104
    00105     /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
    00106      ** No loop unrolling is used. */
    00107     blkCnt = numSamples % 0x4u;
    00108
    00109     while(blkCnt > 0u)
    00110     {
    00111       /* C(m,n) = A(m,n) - B(m,n) */
    00112       /* Subtract, saturate and then store the results in the destination buffer. */
    00113       *pOut++ = __QSUB(*pIn1++, *pIn2++);
    00114
    00115       /* Decrement the loop counter */
    00116       blkCnt--;
    00117     }
    00118
    00119     /* Set status as ARM_MATH_SUCCESS */
    00120     status = ARM_MATH_SUCCESS;
    00121   }
    00122
    00123   /* Return to application */
    00124   return (status);
    00125 }
    00126

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