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      1  1.8  dholland /*	$NetBSD: random.c,v 1.8 2009/08/12 08:44:45 dholland Exp $	*/
      2  1.3       cgd 
      3  1.1       cgd /*
      4  1.3       cgd  * Copyright (c) 1988, 1993
      5  1.3       cgd  *	The Regents of the University of California.  All rights reserved.
      6  1.1       cgd  *
      7  1.1       cgd  * This code is derived from software contributed to Berkeley by
      8  1.1       cgd  * Timothy C. Stoehr.
      9  1.1       cgd  *
     10  1.1       cgd  * Redistribution and use in source and binary forms, with or without
     11  1.1       cgd  * modification, are permitted provided that the following conditions
     12  1.1       cgd  * are met:
     13  1.1       cgd  * 1. Redistributions of source code must retain the above copyright
     14  1.1       cgd  *    notice, this list of conditions and the following disclaimer.
     15  1.1       cgd  * 2. Redistributions in binary form must reproduce the above copyright
     16  1.1       cgd  *    notice, this list of conditions and the following disclaimer in the
     17  1.1       cgd  *    documentation and/or other materials provided with the distribution.
     18  1.5       agc  * 3. Neither the name of the University nor the names of its contributors
     19  1.1       cgd  *    may be used to endorse or promote products derived from this software
     20  1.1       cgd  *    without specific prior written permission.
     21  1.1       cgd  *
     22  1.1       cgd  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23  1.1       cgd  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  1.1       cgd  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  1.1       cgd  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26  1.1       cgd  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  1.1       cgd  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  1.1       cgd  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  1.1       cgd  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  1.1       cgd  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  1.1       cgd  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  1.1       cgd  * SUCH DAMAGE.
     33  1.1       cgd  */
     34  1.1       cgd 
     35  1.4     lukem #include <sys/cdefs.h>
     36  1.1       cgd #ifndef lint
     37  1.3       cgd #if 0
     38  1.3       cgd static char sccsid[] = "@(#)random.c	8.1 (Berkeley) 5/31/93";
     39  1.3       cgd #else
     40  1.8  dholland __RCSID("$NetBSD: random.c,v 1.8 2009/08/12 08:44:45 dholland Exp $");
     41  1.3       cgd #endif
     42  1.1       cgd #endif /* not lint */
     43  1.1       cgd 
     44  1.4     lukem #include "rogue.h"
     45  1.4     lukem 
     46  1.1       cgd /*
     47  1.1       cgd  * random.c
     48  1.1       cgd  *
     49  1.1       cgd  * This source herein may be modified and/or distributed by anybody who
     50  1.1       cgd  * so desires, with the following restrictions:
     51  1.1       cgd  *    1.)  No portion of this notice shall be removed.
     52  1.1       cgd  *    2.)  Credit shall not be taken for the creation of this source.
     53  1.1       cgd  *    3.)  This code is not to be traded, sold, or used for personal
     54  1.1       cgd  *         gain or profit.
     55  1.1       cgd  *
     56  1.1       cgd  */
     57  1.1       cgd 
     58  1.1       cgd static long rntb[32] = {
     59  1.6  dholland 	         3, 0x9a319039, 0x32d9c024, 0x9b663182, 0x5da1f342,
     60  1.1       cgd 	0xde3b81e0, 0xdf0a6fb5, 0xf103bc02, 0x48f340fb, 0x7449e56b,
     61  1.1       cgd 	0xbeb1dbb0, 0xab5c5918, 0x946554fd, 0x8c2e680f, 0xeb3d799f,
     62  1.1       cgd 	0xb11ee0b7, 0x2d436b86, 0xda672e2a, 0x1588ca88, 0xe369735d,
     63  1.6  dholland 	0x904f35f7, 0xd7158fd6, 0x6fa6f051, 0x616e6b96, 0xac94efdc,
     64  1.1       cgd 	0x36413f93, 0xc622c298, 0xf5a42ab8, 0x8a88d77b, 0xf5ad9d0e,
     65  1.1       cgd 	0x8999220b, 0x27fb47b9
     66  1.1       cgd };
     67  1.1       cgd 
     68  1.1       cgd static long *fptr = &rntb[4];
     69  1.1       cgd static long *rptr = &rntb[1];
     70  1.1       cgd static long *state = &rntb[1];
     71  1.1       cgd static int rand_type = 3;
     72  1.1       cgd static int rand_deg = 31;
     73  1.1       cgd static int rand_sep = 3;
     74  1.1       cgd static long *end_ptr = &rntb[32];
     75  1.1       cgd 
     76  1.8  dholland static long rrandom(void);
     77  1.8  dholland 
     78  1.4     lukem void
     79  1.7  dholland srrandom(int x)
     80  1.1       cgd {
     81  1.4     lukem 	int i;
     82  1.1       cgd 
     83  1.7  dholland 	state[0] = x;
     84  1.1       cgd 	if (rand_type != 0) {
     85  1.1       cgd 		for (i = 1; i < rand_deg; i++) {
     86  1.1       cgd 			state[i] = 1103515245 * state[i - 1] + 12345;
     87  1.1       cgd 		}
     88  1.1       cgd 		fptr = &state[rand_sep];
     89  1.1       cgd 		rptr = &state[0];
     90  1.1       cgd 		for (i = 0; i < 10 * rand_deg; i++) {
     91  1.6  dholland 			(void)rrandom();
     92  1.1       cgd 		}
     93  1.1       cgd 	}
     94  1.1       cgd }
     95  1.1       cgd 
     96  1.8  dholland static long
     97  1.7  dholland rrandom(void)
     98  1.1       cgd {
     99  1.1       cgd 	long i;
    100  1.6  dholland 
    101  1.1       cgd 	if (rand_type == 0) {
    102  1.1       cgd 		i = state[0] = (state[0]*1103515245 + 12345) & 0x7fffffff;
    103  1.1       cgd 	} else {
    104  1.1       cgd 		*fptr += *rptr;
    105  1.1       cgd 		i = (*fptr >> 1) & 0x7fffffff;
    106  1.1       cgd 		if (++fptr >= end_ptr) {
    107  1.1       cgd 			fptr = state;
    108  1.1       cgd 			++rptr;
    109  1.1       cgd 		} else {
    110  1.1       cgd 			if (++rptr >= end_ptr) {
    111  1.1       cgd 				rptr = state;
    112  1.1       cgd 			}
    113  1.1       cgd 		}
    114  1.1       cgd 	}
    115  1.1       cgd 	return(i);
    116  1.1       cgd }
    117  1.1       cgd 
    118  1.4     lukem int
    119  1.7  dholland get_rand(int x, int y)
    120  1.1       cgd {
    121  1.4     lukem 	int r, t;
    122  1.1       cgd 	long lr;
    123  1.1       cgd 
    124  1.1       cgd 	if (x > y) {
    125  1.1       cgd 		t = y;
    126  1.1       cgd 		y = x;
    127  1.1       cgd 		x = t;
    128  1.1       cgd 	}
    129  1.1       cgd 	lr = rrandom();
    130  1.7  dholland 	lr &= 0x00003fffL;
    131  1.6  dholland 	r = (int)lr;
    132  1.1       cgd 	r = (r % ((y - x) + 1)) + x;
    133  1.1       cgd 	return(r);
    134  1.1       cgd }
    135  1.1       cgd 
    136  1.4     lukem int
    137  1.7  dholland rand_percent(int percentage)
    138  1.1       cgd {
    139  1.1       cgd 	return(get_rand(1, 100) <= percentage);
    140  1.1       cgd }
    141  1.1       cgd 
    142  1.4     lukem int
    143  1.7  dholland coin_toss(void)
    144  1.1       cgd {
    145  1.1       cgd 	return(((rrandom() & 01) ? 1 : 0));
    146  1.1       cgd }
    147