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# arm_mat_sub_f32.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_f32.c
    00009 *
    00010 * Description:  Floating-point 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
    00064 arm_status arm_mat_sub_f32(
    00065   const arm_matrix_instance_f32 * pSrcA,
    00066   const arm_matrix_instance_f32 * pSrcB,
    00067   arm_matrix_instance_f32 * pDst)
    00068 {
    00069   float32_t *pIn1 = pSrcA->pData;                /* input data matrix pointer A */
    00070   float32_t *pIn2 = pSrcB->pData;                /* input data matrix pointer B */
    00071   float32_t *pOut = pDst->pData;                 /* output data matrix pointer  */
    00072   uint32_t numSamples;                           /* total number of elements in the matrix  */
    00073   uint32_t blkCnt;                               /* loop counters */
    00074   arm_status status;                             /* status of matrix subtraction */
    00075
    00076 #ifdef ARM_MATH_MATRIX_CHECK
    00077   /* Check for matrix mismatch condition */
    00078   if((pSrcA->numRows != pSrcB->numRows) ||
    00079      (pSrcA->numCols != pSrcB->numCols) ||
    00080      (pSrcA->numRows != pDst->numRows) || (pSrcA->numCols != pDst->numCols))
    00081   {
    00082     /* Set status as ARM_MATH_SIZE_MISMATCH */
    00083     status = ARM_MATH_SIZE_MISMATCH;
    00084   }
    00085   else
    00086 #endif
    00087   {
    00088     /* Total number of samples in the input matrix */
    00089     numSamples = (uint32_t) pSrcA->numRows * pSrcA->numCols;
    00090
    00091     /* Loop Unrolling */
    00092     blkCnt = numSamples >> 2u;
    00093
    00094     /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
    00095      ** a second loop below computes the remaining 1 to 3 samples. */
    00096     while(blkCnt > 0u)
    00097     {
    00098       /* C(m,n) = A(m,n) - B(m,n) */
    00099       /* Subtract and then store the results in the destination buffer. */
    00100       *pOut++ = (*pIn1++) - (*pIn2++);
    00101       *pOut++ = (*pIn1++) - (*pIn2++);
    00102       *pOut++ = (*pIn1++) - (*pIn2++);
    00103       *pOut++ = (*pIn1++) - (*pIn2++);
    00104
    00105       /* Decrement the loop counter */
    00106       blkCnt--;
    00107     }
    00108
    00109     /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
    00110      ** No loop unrolling is used. */
    00111     blkCnt = numSamples % 0x4u;
    00112
    00113     while(blkCnt > 0u)
    00114     {
    00115       /* C(m,n) = A(m,n) - B(m,n) */
    00116       /* Subtract and then store the results in the destination buffer. */
    00117       *pOut++ = (*pIn1++) - (*pIn2++);
    00118
    00119       /* Decrement the loop counter */
    00120       blkCnt--;
    00121     }
    00122
    00123     /* Set status as ARM_MATH_SUCCESS */
    00124     status = ARM_MATH_SUCCESS;
    00125   }
    00126
    00127   /* Return to application */
    00128   return (status);
    00129 }
    00130

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