1/*	$OpenBSD: _rand48.c,v 1.3 2005/08/08 08:05:36 espie Exp $ */
2/*
3 * Copyright (c) 1993 Martin Birgmeier
4 * All rights reserved.
5 *
6 * You may redistribute unmodified or modified versions of this source
7 * code provided that the above copyright notice and this and the
8 * following conditions are retained.
9 *
10 * This software is provided ``as is'', and comes with no warranties
11 * of any kind. I shall in no event be liable for anything that happens
12 * to anyone/anything when using this software.
13 */
14
15#include "rand48.h"
16
17unsigned short __rand48_seed[3] = {
18	RAND48_SEED_0,
19	RAND48_SEED_1,
20	RAND48_SEED_2
21};
22unsigned short __rand48_mult[3] = {
23	RAND48_MULT_0,
24	RAND48_MULT_1,
25	RAND48_MULT_2
26};
27unsigned short __rand48_add = RAND48_ADD;
28
29void
30__dorand48(unsigned short xseed[3])
31{
32	unsigned long accu;
33	unsigned short temp[2];
34
35	accu = (unsigned long) __rand48_mult[0] * (unsigned long) xseed[0] +
36	 (unsigned long) __rand48_add;
37	temp[0] = (unsigned short) accu;	/* lower 16 bits */
38	accu >>= sizeof(unsigned short) * 8;
39	accu += (unsigned long) __rand48_mult[0] * (unsigned long) xseed[1] +
40	 (unsigned long) __rand48_mult[1] * (unsigned long) xseed[0];
41	temp[1] = (unsigned short) accu;	/* middle 16 bits */
42	accu >>= sizeof(unsigned short) * 8;
43	accu += __rand48_mult[0] * xseed[2] + __rand48_mult[1] * xseed[1] + __rand48_mult[2] * xseed[0];
44	xseed[0] = temp[0];
45	xseed[1] = temp[1];
46	xseed[2] = (unsigned short) accu;
47}
48