arm_mat_scale_f32.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_scale_f32.c  
00009 *  
00010 * Description:  Multiplies a floating-point matrix by a scalar.  
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  * @defgroup MatrixScale Matrix Scale  
00041  *  
00042  * Multiplies a matrix by a scalar.  This is accomplished by multiplying each element in the  
00043  * matrix by the scalar.  For example:  
00044  * \image html MatrixScale.gif "Matrix Scaling of a 3 x 3 matrix"  
00045  *  
00046  * The function checks to make sure that the input and output matrices are of the same size.  
00047  *  
00048  * In the fixed-point Q15 and Q31 functions, <code>scale</code> is represented by  
00049  * a fractional multiplication <code>scaleFract</code> and an arithmetic shift <code>shift</code>.  
00050  * The shift allows the gain of the scaling operation to exceed 1.0.  
00051  * The overall scale factor applied to the fixed-point data is  
00052  * <pre>  
00053  *     scale = scaleFract * 2^shift.  
00054  * </pre>  
00055  */ 
00056  
00057 /**  
00058  * @addtogroup MatrixScale  
00059  * @{  
00060  */ 
00061  
00062 /**  
00063  * @brief Floating-point matrix scaling.  
00064  * @param[in]       *pSrc points to input matrix structure  
00065  * @param[in]       scale scale factor to be applied   
00066  * @param[out]      *pDst points to output matrix structure  
00067  * @return          The function returns either <code>ARM_MATH_SIZE_MISMATCH</code>   
00068  * or <code>ARM_MATH_SUCCESS</code> based on the outcome of size checking.  
00069  *  
00070  */ 
00071  
00072 arm_status arm_mat_scale_f32( 
00073   const arm_matrix_instance_f32 * pSrc, 
00074   float32_t scale, 
00075   arm_matrix_instance_f32 * pDst) 
00076 { 
00077   float32_t *pIn = pSrc->pData;                  /* input data matrix pointer */ 
00078   float32_t *pOut = pDst->pData;                 /* output data matrix pointer */ 
00079   uint32_t numSamples;                           /* total number of elements in the matrix */ 
00080   uint32_t blkCnt;                               /* loop counters */ 
00081   arm_status status;                             /* status of matrix scaling     */ 
00082  
00083 #ifdef ARM_MATH_MATRIX_CHECK 
00084   /* Check for matrix mismatch condition */ 
00085   if((pSrc->numRows != pDst->numRows) || (pSrc->numCols != pDst->numCols)) 
00086   { 
00087     /* Set status as ARM_MATH_SIZE_MISMATCH */ 
00088     status = ARM_MATH_SIZE_MISMATCH; 
00089   } 
00090   else 
00091 #endif 
00092   { 
00093     /* Total number of samples in the input matrix */ 
00094     numSamples = (uint32_t) pSrc->numRows * pSrc->numCols; 
00095  
00096     /* Loop Unrolling */ 
00097     blkCnt = numSamples >> 2; 
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) * scale */ 
00104       /* Scaling and results are stored in the destination buffer. */ 
00105       *pOut++ = (*pIn++) * scale; 
00106       *pOut++ = (*pIn++) * scale; 
00107       *pOut++ = (*pIn++) * scale; 
00108       *pOut++ = (*pIn++) * scale; 
00109  
00110       /* Decrement the numSamples loop counter */ 
00111       blkCnt--; 
00112     } 
00113  
00114     /* If the numSamples is not a multiple of 4, compute any remaining output samples here.  
00115      ** No loop unrolling is used. */ 
00116     blkCnt = numSamples % 0x4u; 
00117  
00118     while(blkCnt > 0u) 
00119     { 
00120       /* C(m,n) = A(m,n) * scale */ 
00121       /* The results are stored in the destination buffer. */ 
00122       *pOut++ = (*pIn++) * scale; 
00123  
00124       /* Decrement the loop counter */ 
00125       blkCnt--; 
00126     } 
00127  
00128     /* Set status as ARM_MATH_SUCCESS */ 
00129     status = ARM_MATH_SUCCESS; 
00130   } 
00131  
00132   /* Return to application */ 
00133   return (status); 
00134 } 
00135  
00136 /**  
00137  * @} end of MatrixScale group  
00138  */