Centre Blaise Pascal » HPL sur GPU

/* 

 * -- High Performance Computing Linpack Benchmark (HPL)                

 *    HPL - 2.0 - September 10, 2008                          

 *    Antoine P. Petitet                                                

 *    University of Tennessee, Knoxville                                

 *    Innovative Computing Laboratory                                 

 *    (C) Copyright 2000-2008 All Rights Reserved                       

 *                                                                      

 * -- Copyright notice and Licensing terms:                             

 *                                                                      

 * Redistribution  and  use in  source and binary forms, with or without

 * modification, are  permitted provided  that the following  conditions

 * are met:                                                             

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 * notice, this list of conditions and the following disclaimer.        

 *                                                                      

 * 2. Redistributions in binary form must reproduce  the above copyright

 * notice, this list of conditions,  and the following disclaimer in the

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 *                                                                      

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 * software must display the following acknowledgement:                 

 * This  product  includes  software  developed  at  the  University  of

 * Tennessee, Knoxville, Innovative Computing Laboratory.             

 *                                                                      

 * 4. The name of the  University,  the name of the  Laboratory,  or the

 * names  of  its  contributors  may  not  be used to endorse or promote

 * products  derived   from   this  software  without  specific  written

 * permission.                                                          

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 * -- Disclaimer:                                                       

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 * THIS  SOFTWARE  IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,  INCLUDING,  BUT NOT

 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY

 * OR  CONTRIBUTORS  BE  LIABLE FOR ANY  DIRECT,  INDIRECT,  INCIDENTAL,

 * SPECIAL,  EXEMPLARY,  OR  CONSEQUENTIAL DAMAGES  (INCLUDING,  BUT NOT

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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 

 * ---------------------------------------------------------------------

 */ 

/*

 * Include files

 */

#include "hpl.h"

#ifdef STDC_HEADERS

void HPL_lmul

(

   int *                            K,

   int *                            J,

   int *                            I

)

#else

void HPL_lmul

( K, J, I )

   int *                            K;

   int *                            J;

   int *                            I;

#endif

{

/* 

 * Purpose

 * =======

 *

 * HPL_lmul multiplies  without carry two long positive integers K and J

 * and puts the result into I. The long integers  I, J, K are encoded on

 * 32 bits using an array of 2 integers. The 32-lower bits are stored in

 * the first entry of each array, the 32-higher bits in the second entry

 * of each array. For efficiency purposes, the  intrisic modulo function

 * is inlined.

 *

 * Arguments

 * =========

 *

 * K       (local input)                 int *

 *         On entry, K is an integer array of dimension 2 containing the

 *         encoded long integer K.

 *

 * J       (local input)                 int *

 *         On entry, J is an integer array of dimension 2 containing the

 *         encoded long integer J.

 *

 * I       (local output)                int *

 *         On entry, I is an integer array of dimension 2. On exit, this

 *         array contains the encoded long integer result.

 *

 * ---------------------------------------------------------------------

 */ 

/*

 * .. Local Variables ..

 */

   int                        r, c;

   unsigned int               kk[4], jj[4], res[5];

/* ..

 * .. Executable Statements ..

 */

/*

 * Addition is done with 16 bits at a time. Multiplying two 16-bit

 * integers yields a 32-bit result. The lower 16-bits of the result

 * are kept in I, and the higher 16-bits are carried over to the

 * next multiplication.

 */

   for (c = 0; c < 2; ++c) {

     kk[2*c] = K[c] & 65535;

     kk[2*c+1] = ((unsigned)K[c] >> 16) & 65535;

     jj[2*c] = J[c] & 65535;

     jj[2*c+1] = ((unsigned)J[c] >> 16) & 65535;

   }

   res[0] = 0;

   for (c = 0; c < 4; ++c) {

     res[c+1] = (res[c] >> 16) & 65535;

     res[c] &= 65535;

     for (r = 0; r < c+1; ++r) {

       res[c] = kk[r] * jj[c-r] + (res[c] & 65535);

       res[c+1] += (res[c] >> 16) & 65535;

     }

   }

   for (c = 0; c < 2; ++c)

     I[c] = (int)(((res[2*c+1] & 65535) << 16) | (res[2*c] & 65535));

/*

 * End of HPL_lmul

 */

}