arm_mat_sub_q31.c

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_q31.c  
00009 *  
00010 * Description:  Q31 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  
00035 /**  
00036  * @ingroup groupMatrix  
00037  */ 
00038  
00039 /**  
00040  * @addtogroup MatrixSub  
00041  * @{  
00042  */ 
00043  
00044 /**  
00045  * @brief Q31 matrix subtraction.  
00046  * @param[in]       *pSrcA points to the first input matrix structure  
00047  * @param[in]       *pSrcB points to the second input matrix structure  
00048  * @param[out]      *pDst points to output matrix structure  
00049  * @return          The function returns either  
00050  * <code>ARM_MATH_SIZE_MISMATCH</code> or <code>ARM_MATH_SUCCESS</code> based on the outcome of size checking.  
00051  *  
00052  * <b>Scaling and Overflow Behavior:</b>  
00053  * \par  
00054  * The function uses saturating arithmetic.  
00055  * Results outside of the allowable Q31 range [0x80000000 0x7FFFFFFF] will be saturated.  
00056  */ 
00057  
00058  
00059 arm_status arm_mat_sub_q31( 
00060   const arm_matrix_instance_q31 * pSrcA, 
00061   const arm_matrix_instance_q31 * pSrcB, 
00062   arm_matrix_instance_q31 * pDst) 
00063 { 
00064   q31_t *pIn1 = pSrcA->pData;                    /* input data matrix pointer A */ 
00065   q31_t *pIn2 = pSrcB->pData;                    /* input data matrix pointer B */ 
00066   q31_t *pOut = pDst->pData;                     /* output data matrix pointer */ 
00067   uint32_t numSamples;                           /* total number of elements in the matrix  */ 
00068   uint32_t blkCnt;                               /* loop counters */ 
00069   arm_status status;                             /* status of matrix subtraction */ 
00070  
00071  
00072 #ifdef ARM_MATH_MATRIX_CHECK 
00073   /* Check for matrix mismatch condition  */ 
00074   if((pSrcA->numRows != pSrcB->numRows) || 
00075      (pSrcA->numCols != pSrcB->numCols) || 
00076      (pSrcA->numRows != pDst->numRows) || (pSrcA->numCols != pDst->numCols)) 
00077   { 
00078     /* Set status as ARM_MATH_SIZE_MISMATCH */ 
00079     status = ARM_MATH_SIZE_MISMATCH; 
00080   } 
00081   else 
00082 #endif 
00083   { 
00084     /* Total number of samples in the input matrix */ 
00085     numSamples = (uint32_t) pSrcA->numRows * pSrcA->numCols; 
00086  
00087     /* Loop Unrolling */ 
00088     blkCnt = numSamples >> 2u; 
00089  
00090     /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.  
00091      ** a second loop below computes the remaining 1 to 3 samples. */ 
00092     while(blkCnt > 0u) 
00093     { 
00094       /* C(m,n) = A(m,n) - B(m,n) */ 
00095       /* Subtract, saturate and then store the results in the destination buffer. */ 
00096       *pOut++ = __QSUB(*pIn1++, *pIn2++); 
00097       *pOut++ = __QSUB(*pIn1++, *pIn2++); 
00098       *pOut++ = __QSUB(*pIn1++, *pIn2++); 
00099       *pOut++ = __QSUB(*pIn1++, *pIn2++); 
00100  
00101       /* Decrement the loop counter */ 
00102       blkCnt--; 
00103     } 
00104  
00105     /* If the numSamples is not a multiple of 4, compute any remaining output samples here.  
00106      ** No loop unrolling is used. */ 
00107     blkCnt = numSamples % 0x4u; 
00108  
00109     while(blkCnt > 0u) 
00110     { 
00111       /* C(m,n) = A(m,n) - B(m,n) */ 
00112       /* Subtract, saturate and then store the results in the destination buffer. */ 
00113       *pOut++ = __QSUB(*pIn1++, *pIn2++); 
00114  
00115       /* Decrement the loop counter */ 
00116       blkCnt--; 
00117     } 
00118  
00119     /* Set status as ARM_MATH_SUCCESS */ 
00120     status = ARM_MATH_SUCCESS; 
00121   } 
00122  
00123   /* Return to application */ 
00124   return (status); 
00125 } 
00126  
00127 /**  
00128  * @} end of MatrixSub group  
00129  */