tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/MatrixFunctions/arm_mat_sub_q15.c

   1 /* ----------------------------------------------------------------------
   2 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.
   3 *
   4 * $Date:        17. January 2013
   5 * $Revision:    V1.4.1
   6 *
   7 * Project:          CMSIS DSP Library
   8 * Title:            arm_mat_sub_q15.c
   9 *
  10 * Description:  Q15 Matrix subtraction
  11 *
  12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
  13 *
  14 * Redistribution and use in source and binary forms, with or without
  15 * modification, are permitted provided that the following conditions
  16 * are met:
  17 *   - Redistributions of source code must retain the above copyright
  18 *     notice, this list of conditions and the following disclaimer.
  19 *   - Redistributions in binary form must reproduce the above copyright
  20 *     notice, this list of conditions and the following disclaimer in
  21 *     the documentation and/or other materials provided with the
  22 *     distribution.
  23 *   - Neither the name of ARM LIMITED nor the names of its contributors
  24 *     may be used to endorse or promote products derived from this
  25 *     software without specific prior written permission.
  26 *
  27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  30 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  31 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  33 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  34 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  35 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  38 * POSSIBILITY OF SUCH DAMAGE.
  39 * -------------------------------------------------------------------- */
  40
  41 #include "arm_math.h"
  42
  43 /**
  44  * @ingroup groupMatrix
  45  */
  46
  47 /**
  48  * @addtogroup MatrixSub
  49  * @{
  50  */
  51
  52 /**
  53  * @brief Q15 matrix subtraction.
  54  * @param[in]       *pSrcA points to the first input matrix structure
  55  * @param[in]       *pSrcB points to the second input matrix structure
  56  * @param[out]      *pDst points to output matrix structure
  57  * @return              The function returns either
  58  * <code>ARM_MATH_SIZE_MISMATCH</code> or <code>ARM_MATH_SUCCESS</code> based on the outcome of size checking.
  59  *
  60  * <b>Scaling and Overflow Behavior:</b>
  61  * \par
  62  * The function uses saturating arithmetic.
  63  * Results outside of the allowable Q15 range [0x8000 0x7FFF] will be saturated.
  64  */
  65
  66 arm_status arm_mat_sub_q15(
  67   const arm_matrix_instance_q15 * pSrcA,
  68   const arm_matrix_instance_q15 * pSrcB,
  69   arm_matrix_instance_q15 * pDst)
  70 {
  71   q15_t *pInA = pSrcA->pData;                    /* input data matrix pointer A */
  72   q15_t *pInB = pSrcB->pData;                    /* input data matrix pointer B */
  73   q15_t *pOut = pDst->pData;                     /* output data matrix pointer */
  74   uint32_t numSamples;                           /* total number of elements in the matrix */
  75   uint32_t blkCnt;                               /* loop counters  */
  76   arm_status status;                             /* status of matrix subtraction  */
  77
  78
  79 #ifdef ARM_MATH_MATRIX_CHECK
  80
  81
  82   /* Check for matrix mismatch condition */
  83   if((pSrcA->numRows != pSrcB->numRows) ||
  84      (pSrcA->numCols != pSrcB->numCols) ||
  85      (pSrcA->numRows != pDst->numRows) || (pSrcA->numCols != pDst->numCols))
  86   {
  87     /* Set status as ARM_MATH_SIZE_MISMATCH */
  88     status = ARM_MATH_SIZE_MISMATCH;
  89   }
  90   else
  91 #endif /*    #ifdef ARM_MATH_MATRIX_CHECK    */
  92
  93   {
  94     /* Total number of samples in the input matrix */
  95     numSamples = (uint32_t) pSrcA->numRows * pSrcA->numCols;
  96
  97 #ifndef ARM_MATH_CM0_FAMILY
  98
  99     /* Run the below code for Cortex-M4 and Cortex-M3 */
 100
 101     /* Apply loop unrolling */
 102     blkCnt = numSamples >> 2u;
 103
 104     /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
 105      ** a second loop below computes the remaining 1 to 3 samples. */
 106     while(blkCnt > 0u)
 107     {
 108       /* C(m,n) = A(m,n) - B(m,n) */
 109       /* Subtract, Saturate and then store the results in the destination buffer. */
 110       *__SIMD32(pOut)++ = __QSUB16(*__SIMD32(pInA)++, *__SIMD32(pInB)++);
 111       *__SIMD32(pOut)++ = __QSUB16(*__SIMD32(pInA)++, *__SIMD32(pInB)++);
 112
 113       /* Decrement the loop counter */
 114       blkCnt--;
 115     }
 116
 117     /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
 118      ** No loop unrolling is used. */
 119     blkCnt = numSamples % 0x4u;
 120
 121     while(blkCnt > 0u)
 122     {
 123       /* C(m,n) = A(m,n) - B(m,n) */
 124       /* Subtract and then store the results in the destination buffer. */
 125       *pOut++ = (q15_t) __QSUB16(*pInA++, *pInB++);
 126
 127       /* Decrement the loop counter */
 128       blkCnt--;
 129     }
 130
 131 #else
 132
 133     /* Run the below code for Cortex-M0 */
 134
 135     /* Initialize blkCnt with number of samples */
 136     blkCnt = numSamples;
 137
 138     while(blkCnt > 0u)
 139     {
 140       /* C(m,n) = A(m,n) - B(m,n) */
 141       /* Subtract and then store the results in the destination buffer. */
 142       *pOut++ = (q15_t) __SSAT(((q31_t) * pInA++ - *pInB++), 16);
 143
 144       /* Decrement the loop counter */
 145       blkCnt--;
 146     }
 147
 148 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
 149
 150     /* Set status as ARM_MATH_SUCCESS */
 151     status = ARM_MATH_SUCCESS;
 152   }
 153
 154   /* Return to application */
 155   return (status);
 156 }
 157
 158 /**
 159  * @} end of MatrixSub group
 160  */