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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_q31.c    
  9. *    
  10. * Description:  Q31 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 Q31 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 Q31 range [0x80000000 0x7FFFFFFF] will be saturated.        
  64.  */
  65.  
  66.  
  67. arm_status arm_mat_sub_q31(
  68.   const arm_matrix_instance_q31 * pSrcA,
  69.   const arm_matrix_instance_q31 * pSrcB,
  70.   arm_matrix_instance_q31 * pDst)
  71. {
  72.   q31_t *pIn1 = pSrcA->pData;                    /* input data matrix pointer A */
  73.   q31_t *pIn2 = pSrcB->pData;                    /* input data matrix pointer B */
  74.   q31_t *pOut = pDst->pData;                     /* output data matrix pointer */
  75.   q31_t inA1, inB1;                              /* temporary variables */
  76.  
  77. #ifndef ARM_MATH_CM0_FAMILY
  78.  
  79.   q31_t inA2, inB2;                              /* temporary variables */
  80.   q31_t out1, out2;                              /* temporary variables */
  81.  
  82. #endif //      #ifndef ARM_MATH_CM0_FAMILY
  83.  
  84.   uint32_t numSamples;                           /* total number of elements in the matrix  */
  85.   uint32_t blkCnt;                               /* loop counters */
  86.   arm_status status;                             /* status of matrix subtraction */
  87.  
  88.  
  89. #ifdef ARM_MATH_MATRIX_CHECK
  90.   /* Check for matrix mismatch condition  */
  91.   if((pSrcA->numRows != pSrcB->numRows) ||
  92.      (pSrcA->numCols != pSrcB->numCols) ||
  93.      (pSrcA->numRows != pDst->numRows) || (pSrcA->numCols != pDst->numCols))
  94.   {
  95.     /* Set status as ARM_MATH_SIZE_MISMATCH */
  96.     status = ARM_MATH_SIZE_MISMATCH;
  97.   }
  98.   else
  99. #endif
  100.   {
  101.     /* Total number of samples in the input matrix */
  102.     numSamples = (uint32_t) pSrcA->numRows * pSrcA->numCols;
  103.  
  104. #ifndef ARM_MATH_CM0_FAMILY
  105.  
  106.     /* Run the below code for Cortex-M4 and Cortex-M3 */
  107.  
  108.     /* Loop Unrolling */
  109.     blkCnt = numSamples >> 2u;
  110.  
  111.     /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.    
  112.      ** a second loop below computes the remaining 1 to 3 samples. */
  113.     while(blkCnt > 0u)
  114.     {
  115.       /* C(m,n) = A(m,n) - B(m,n) */
  116.       /* Subtract, saturate and then store the results in the destination buffer. */
  117.       /* Read values from source A */
  118.       inA1 = pIn1[0];
  119.  
  120.       /* Read values from source B */
  121.       inB1 = pIn2[0];
  122.  
  123.       /* Read values from source A */
  124.       inA2 = pIn1[1];
  125.  
  126.       /* Subtract and saturate */
  127.       out1 = __QSUB(inA1, inB1);
  128.  
  129.       /* Read values from source B */
  130.       inB2 = pIn2[1];
  131.  
  132.       /* Read values from source A */
  133.       inA1 = pIn1[2];
  134.  
  135.       /* Subtract and saturate */
  136.       out2 = __QSUB(inA2, inB2);
  137.  
  138.       /* Read values from source B */
  139.       inB1 = pIn2[2];
  140.  
  141.       /* Store result in destination */
  142.       pOut[0] = out1;
  143.       pOut[1] = out2;
  144.  
  145.       /* Read values from source A */
  146.       inA2 = pIn1[3];
  147.  
  148.       /* Read values from source B */
  149.       inB2 = pIn2[3];
  150.  
  151.       /* Subtract and saturate */
  152.       out1 = __QSUB(inA1, inB1);
  153.  
  154.       /* Subtract and saturate */
  155.       out2 = __QSUB(inA2, inB2);
  156.  
  157.       /* Store result in destination */
  158.       pOut[2] = out1;
  159.       pOut[3] = out2;
  160.  
  161.       /* update pointers to process next samples */
  162.       pIn1 += 4u;
  163.       pIn2 += 4u;
  164.       pOut += 4u;
  165.  
  166.       /* Decrement the loop counter */
  167.       blkCnt--;
  168.     }
  169.  
  170.     /* If the numSamples is not a multiple of 4, compute any remaining output samples here.        
  171.      ** No loop unrolling is used. */
  172.     blkCnt = numSamples % 0x4u;
  173.  
  174. #else
  175.  
  176.     /* Run the below code for Cortex-M0 */
  177.  
  178.     /* Initialize blkCnt with number of samples */
  179.     blkCnt = numSamples;
  180.  
  181. #endif /* #ifndef ARM_MATH_CM0_FAMILY */
  182.  
  183.     while(blkCnt > 0u)
  184.     {
  185.       /* C(m,n) = A(m,n) - B(m,n) */
  186.       /* Subtract, saturate and then store the results in the destination buffer. */
  187.       inA1 = *pIn1++;
  188.       inB1 = *pIn2++;
  189.  
  190.       inA1 = __QSUB(inA1, inB1);
  191.  
  192.       *pOut++ = inA1;
  193.  
  194.       /* Decrement the loop counter */
  195.       blkCnt--;
  196.     }
  197.  
  198.     /* Set status as ARM_MATH_SUCCESS */
  199.     status = ARM_MATH_SUCCESS;
  200.   }
  201.  
  202.   /* Return to application */
  203.   return (status);
  204. }
  205.  
  206. /**        
  207.  * @} end of MatrixSub group        
  208.  */
  209.