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9acf1ca50d
It's a PRNG using the simple and fast xorshift method. Signed-off-by: Michael Walle <michael@walle.cc> Cc: Wolfgang Denk <wd@denx.de>
48 lines
1.2 KiB
C
48 lines
1.2 KiB
C
/*
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* Simple xorshift PRNG
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* see http://www.jstatsoft.org/v08/i14/paper
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*
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* Copyright (c) 2012 Michael Walle
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* Michael Walle <michael@walle.cc>
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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#include <common.h>
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static unsigned int y = 1U;
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unsigned int rand_r(unsigned int *seedp)
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{
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*seedp ^= (*seedp << 13);
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*seedp ^= (*seedp >> 17);
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*seedp ^= (*seedp << 5);
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return *seedp;
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}
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unsigned int rand(void)
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{
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return rand_r(&y);
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}
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void srand(unsigned int seed)
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{
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y = seed;
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}
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