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# arm_mat_sub_q15.c

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    00001 /* ----------------------------------------------------------------------
    00002 * Copyright (C) 2010 ARM Limited. All rights reserved.
    00003 *
    00004 * $Date:        15. July 2011
    00005 * $Revision:    V1.0.10
    00006 *
    00007 * Project:      CMSIS DSP Library
    00008 * Title:        arm_mat_sub_q15.c
    00009 *
    00010 * Description:  Q15 Matrix subtraction
    00011 *
    00012 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
    00013 *
    00014 * Version 1.0.10 2011/7/15
    00015 *    Big Endian support added and Merged M0 and M3/M4 Source code.
    00016 *
    00017 * Version 1.0.3 2010/11/29
    00018 *    Re-organized the CMSIS folders and updated documentation.
    00019 *
    00020 * Version 1.0.2 2010/11/11
    00021 *    Documentation updated.
    00022 *
    00023 * Version 1.0.1 2010/10/05
    00024 *    Production release and review comments incorporated.
    00025 *
    00026 * Version 1.0.0 2010/09/20
    00027 *    Production release and review comments incorporated.
    00028 *
    00029 * Version 0.0.5  2010/04/26
    00030 *    incorporated review comments and updated with latest CMSIS layer
    00031 *
    00032 * Version 0.0.3  2010/03/10
    00033 *    Initial version
    00034 * -------------------------------------------------------------------- */
    00035
    00036 #include "arm_math.h"
    00037
    00061 arm_status arm_mat_sub_q15(
    00062   const arm_matrix_instance_q15 * pSrcA,
    00063   const arm_matrix_instance_q15 * pSrcB,
    00064   arm_matrix_instance_q15 * pDst)
    00065 {
    00066   q15_t *pInA = pSrcA->pData;                    /* input data matrix pointer A */
    00067   q15_t *pInB = pSrcB->pData;                    /* input data matrix pointer B */
    00068   q15_t *pOut = pDst->pData;                     /* output data matrix pointer */
    00069   uint32_t numSamples;                           /* total number of elements in the matrix */
    00070   uint32_t blkCnt;                               /* loop counters  */
    00071   arm_status status;                             /* status of matrix subtraction  */
    00072
    00073
    00074 #ifdef ARM_MATH_MATRIX_CHECK
    00075
    00076
    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 /*    #ifdef ARM_MATH_MATRIX_CHECK    */
    00087
    00088   {
    00089     /* Total number of samples in the input matrix */
    00090     numSamples = (uint32_t) pSrcA->numRows * pSrcA->numCols;
    00091
    00092 #ifndef ARM_MATH_CM0
    00093
    00094     /* Run the below code for Cortex-M4 and Cortex-M3 */
    00095
    00096     /* Apply loop unrolling */
    00097     blkCnt = numSamples >> 2u;
    00098
    00099     /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
    00100      ** a second loop below computes the remaining 1 to 3 samples. */
    00101     while(blkCnt > 0u)
    00102     {
    00103       /* C(m,n) = A(m,n) - B(m,n) */
    00104       /* Subtract, Saturate and then store the results in the destination buffer. */
    00105       *__SIMD32(pOut)++ = __QSUB16(*__SIMD32(pInA)++, *__SIMD32(pInB)++);
    00106       *__SIMD32(pOut)++ = __QSUB16(*__SIMD32(pInA)++, *__SIMD32(pInB)++);
    00107
    00108       /* Decrement the loop counter */
    00109       blkCnt--;
    00110     }
    00111
    00112     /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
    00113      ** No loop unrolling is used. */
    00114     blkCnt = numSamples % 0x4u;
    00115
    00116     while(blkCnt > 0u)
    00117     {
    00118       /* C(m,n) = A(m,n) - B(m,n) */
    00119       /* Subtract and then store the results in the destination buffer. */
    00120       *pOut++ = (q15_t) __QSUB16(*pInA++, *pInB++);
    00121
    00122       /* Decrement the loop counter */
    00123       blkCnt--;
    00124     }
    00125
    00126 #else
    00127
    00128     /* Run the below code for Cortex-M0 */
    00129
    00130     /* Initialize blkCnt with number of samples */
    00131     blkCnt = numSamples;
    00132
    00133     while(blkCnt > 0u)
    00134     {
    00135       /* C(m,n) = A(m,n) - B(m,n) */
    00136       /* Subtract and then store the results in the destination buffer. */
    00137       *pOut++ = (q15_t) __SSAT(((q31_t) * pInA++ - *pInB++), 16);
    00138
    00139       /* Decrement the loop counter */
    00140       blkCnt--;
    00141     }
    00142
    00143 #endif /* #ifndef ARM_MATH_CM0 */
    00144
    00145     /* Set status as ARM_MATH_SUCCESS */
    00146     status = ARM_MATH_SUCCESS;
    00147   }
    00148
    00149   /* Return to application */
    00150   return (status);
    00151 }
    00152

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