summaryrefslogtreecommitdiffstats
path: root/qemu/roms/u-boot/lib/rand.c
blob: 5c367e186f9d38b6bc82002cec1f81a6d4efa7c8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
/*
 * Simple xorshift PRNG
 *   see http://www.jstatsoft.org/v08/i14/paper
 *
 * Copyright (c) 2012 Michael Walle
 * Michael Walle <michael@walle.cc>
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#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;
}