sscal.h

Nividia提供的CUDA的BLAS库源码

/*
 * Copyright 1993-2008 NVIDIA Corporation.  All rights reserved.
 *
 * NOTICE TO USER:   
 *
 * This source code is subject to NVIDIA ownership rights under U.S. and
 * international Copyright laws.  
 *
 * This software and the information contained herein is being provided 
 * under the terms and conditions of a Source Code License Agreement.     
 *
 * NVIDIA MAKES NO REPRESENTATION ABOUT THE SUITABILITY OF THIS SOURCE
 * CODE FOR ANY PURPOSE.  IT IS PROVIDED "AS IS" WITHOUT EXPRESS OR 
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 * MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE.
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 * OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
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 * OR PERFORMANCE OF THIS SOURCE CODE.  
 *
 * U.S. Government End Users.   This source code is a "commercial item" as 
 * that term is defined at  48 C.F.R. 2.101 (OCT 1995), consisting  of
 * "commercial computer  software"  and "commercial computer software 
 * documentation" as such terms are  used in 48 C.F.R. 12.212 (SEPT 1995)
 * and is provided to the U.S. Government only as a commercial end item.
 * Consistent with 48 C.F.R.12.212 and 48 C.F.R. 227.7202-1 through
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 * source code with only those rights set forth herein.
 */

#if (USE_TEX==1)
#undef fetchx
#define fetchx(i)  tex1Dfetch(texX,parms.texXOfs+(i))
#else
#undef fetchx
#define fetchx(i)  sx[i]
#endif /* USE_TEX */

    int i, n, tid, totalThreads, ctaStart;
    float *sx;

    /* NOTE: wrapper must ensure that parms.n > 0 and parms.incx > 0 */
    tid = threadIdx.x;
    n = parms.n;
    sx = parms.sx;
    totalThreads = gridDim.x * blockDim.x;
    ctaStart = blockDim.x * blockIdx.x;
    
    if (parms.incx == 1) {
        /* increment equal to 1 */
        for (i = ctaStart + tid; i < parms.n; i += totalThreads) {
            sx[i] = fetchx(i) * parms.sa;
        }
    } else {
        /* increment not equal to 1 */
        int ix = ((parms.incx < 0) ? ((1 - n) * parms.incx) : 0);
        for (i = ctaStart + tid; i < parms.n; i += totalThreads) {
            sx[ix+i*parms.incx] = fetchx(ix+i*parms.incx) * parms.sa;
        }
    }