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/*
* Copyright (c) 2002-2006 Hewlett-Packard Development Company, L.P.
* Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
* 02111-1307 USA
*/
#include <linux/types.h>
#include <linux/module.h>
/*
* Fast, simple, yet decent quality random number generator based on
* a paper by David G. Carta ("Two Fast Implementations of the
* `Minimal Standard' Random Number Generator," Communications of the
* ACM, January, 1990).
*/
u64 carta_random32 (u64 seed)
{
# define A 16807
# define M ((u32) 1 << 31)
u64 s, prod = A * seed, p, q;
p = (prod >> 31) & (M - 1);
q = (prod >> 0) & (M - 1);
s = p + q;
if (s >= M)
s -= M - 1;
return s;
}
EXPORT_SYMBOL_GPL(carta_random32);
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