1/*
2 * Copyright (c) 1993 Martin Birgmeier
3 * All rights reserved.
4 *
5 * You may redistribute unmodified or modified versions of this source
6 * code provided that the above copyright notice and this and the
7 * following conditions are retained.
8 *
9 * This software is provided ``as is'', and comes with no warranties
10 * of any kind. I shall in no event be liable for anything that happens
11 * to anyone/anything when using this software.
12 */
13
14#include <sys/cdefs.h>
15__FBSDID("$FreeBSD$");
16
17#include "rand48.h"
18
19unsigned short _rand48_seed[3] = {
20	RAND48_SEED_0,
21	RAND48_SEED_1,
22	RAND48_SEED_2
23};
24unsigned short _rand48_mult[3] = {
25	RAND48_MULT_0,
26	RAND48_MULT_1,
27	RAND48_MULT_2
28};
29unsigned short _rand48_add = RAND48_ADD;
30
31void
32_dorand48(unsigned short xseed[3])
33{
34	unsigned long accu;
35	unsigned short temp[2];
36
37	accu = (unsigned long) _rand48_mult[0] * (unsigned long) xseed[0] +
38	 (unsigned long) _rand48_add;
39	temp[0] = (unsigned short) accu;	/* lower 16 bits */
40	accu >>= sizeof(unsigned short) * 8;
41	accu += (unsigned long) _rand48_mult[0] * (unsigned long) xseed[1] +
42	 (unsigned long) _rand48_mult[1] * (unsigned long) xseed[0];
43	temp[1] = (unsigned short) accu;	/* middle 16 bits */
44	accu >>= sizeof(unsigned short) * 8;
45	accu += _rand48_mult[0] * xseed[2] + _rand48_mult[1] * xseed[1] + _rand48_mult[2] * xseed[0];
46	xseed[0] = temp[0];
47	xseed[1] = temp[1];
48	xseed[2] = (unsigned short) accu;
49}
50