tsiry-sandratraina.com
A modern Music Player Daemon based on Rockbox open source high quality audio player
libadwaita
audio
rust
zig
deno
mpris
rockbox
mpd
1/* random.c - Z-machine random number generator
2 * Copyright (c) 1995-1997 Stefan Jokisch
3 *
4 * This file is part of Frotz.
5 *
6 * Frotz is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * Frotz is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
19 */
20
21#include "frotz.h"
22
23static long A = 1;
24
25static int interval = 0;
26static int counter = 0;
27
28/*
29 * seed_random
30 *
31 * Set the seed value for the random number generator.
32 *
33 */
34
35void seed_random (int value)
36{
37
38 if (value == 0) { /* ask interface for seed value */
39 A = os_random_seed ();
40 interval = 0;
41 } else if (value < 1000) { /* special seed value */
42 counter = 0;
43 interval = value;
44 } else { /* standard seed value */
45 A = value;
46 interval = 0;
47 }
48
49}/* seed_random */
50
51/*
52 * z_random, store a random number or set the random number seed.
53 *
54 * zargs[0] = range (positive) or seed value (negative)
55 *
56 */
57
58void z_random ()
59{
60
61 if ((short) zargs[0] <= 0) { /* set random seed */
62
63 seed_random (- (short) zargs[0]);
64 store (0);
65
66 } else { /* generate random number */
67
68 zword result;
69
70 if (interval != 0) { /* ...in special mode */
71 result = counter++;
72 if (counter == interval) counter = 0;
73 } else { /* ...in standard mode */
74 A = 0x015a4e35L * A + 1;
75 result = (A >> 16) & 0x7fff;
76 }
77
78 store ((zword) (result % zargs[0] + 1));
79
80 }
81
82}/* z_random */