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  1. /* ----------------------------------------------------------------------    
  2. * Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
  3. *    
  4. * $Date:        19. March 2015
  5. * $Revision:    V.1.4.5
  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.  */
  161.