mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-11-30 08:31:03 +00:00
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
/*
|
|
* Simple xorshift PRNG
|
|
* see http://www.jstatsoft.org/v08/i14/paper
|
|
*
|
|
* Copyright (c) 2012 Michael Walle
|
|
* Michael Walle <michael@walle.cc>
|
|
*
|
|
* See file CREDITS for list of people who contributed to this
|
|
* project.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License as
|
|
* published by the Free Software Foundation; either version 2 of
|
|
* the License, or (at your option) any later version.
|
|
*
|
|
* 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 <common.h>
|
|
|
|
static unsigned int y = 1U;
|
|
|
|
unsigned int rand_r(unsigned int *seedp)
|
|
{
|
|
*seedp ^= (*seedp << 13);
|
|
*seedp ^= (*seedp >> 17);
|
|
*seedp ^= (*seedp << 5);
|
|
|
|
return *seedp;
|
|
}
|
|
|
|
unsigned int rand(void)
|
|
{
|
|
return rand_r(&y);
|
|
}
|
|
|
|
void srand(unsigned int seed)
|
|
{
|
|
y = seed;
|
|
}
|