1 /* $NetBSD: random.c,v 1.4 1997/10/12 11:45:43 lukem Exp $ */ 2 3 /* 4 * Copyright (c) 1988, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Timothy C. Stoehr. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 #ifndef lint 41 #if 0 42 static char sccsid[] = "@(#)random.c 8.1 (Berkeley) 5/31/93"; 43 #else 44 __RCSID("$NetBSD: random.c,v 1.4 1997/10/12 11:45:43 lukem Exp $"); 45 #endif 46 #endif /* not lint */ 47 48 #include "rogue.h" 49 50 /* 51 * random.c 52 * 53 * This source herein may be modified and/or distributed by anybody who 54 * so desires, with the following restrictions: 55 * 1.) No portion of this notice shall be removed. 56 * 2.) Credit shall not be taken for the creation of this source. 57 * 3.) This code is not to be traded, sold, or used for personal 58 * gain or profit. 59 * 60 */ 61 62 static long rntb[32] = { 63 3, 0x9a319039, 0x32d9c024, 0x9b663182, 0x5da1f342, 64 0xde3b81e0, 0xdf0a6fb5, 0xf103bc02, 0x48f340fb, 0x7449e56b, 65 0xbeb1dbb0, 0xab5c5918, 0x946554fd, 0x8c2e680f, 0xeb3d799f, 66 0xb11ee0b7, 0x2d436b86, 0xda672e2a, 0x1588ca88, 0xe369735d, 67 0x904f35f7, 0xd7158fd6, 0x6fa6f051, 0x616e6b96, 0xac94efdc, 68 0x36413f93, 0xc622c298, 0xf5a42ab8, 0x8a88d77b, 0xf5ad9d0e, 69 0x8999220b, 0x27fb47b9 70 }; 71 72 static long *fptr = &rntb[4]; 73 static long *rptr = &rntb[1]; 74 static long *state = &rntb[1]; 75 static int rand_type = 3; 76 static int rand_deg = 31; 77 static int rand_sep = 3; 78 static long *end_ptr = &rntb[32]; 79 80 void 81 srrandom(x) 82 int x; 83 { 84 int i; 85 86 state[0] = (long) x; 87 if (rand_type != 0) { 88 for (i = 1; i < rand_deg; i++) { 89 state[i] = 1103515245 * state[i - 1] + 12345; 90 } 91 fptr = &state[rand_sep]; 92 rptr = &state[0]; 93 for (i = 0; i < 10 * rand_deg; i++) { 94 (void) rrandom(); 95 } 96 } 97 } 98 99 long 100 rrandom() 101 { 102 long i; 103 104 if (rand_type == 0) { 105 i = state[0] = (state[0]*1103515245 + 12345) & 0x7fffffff; 106 } else { 107 *fptr += *rptr; 108 i = (*fptr >> 1) & 0x7fffffff; 109 if (++fptr >= end_ptr) { 110 fptr = state; 111 ++rptr; 112 } else { 113 if (++rptr >= end_ptr) { 114 rptr = state; 115 } 116 } 117 } 118 return(i); 119 } 120 121 int 122 get_rand(x, y) 123 int x, y; 124 { 125 int r, t; 126 long lr; 127 128 if (x > y) { 129 t = y; 130 y = x; 131 x = t; 132 } 133 lr = rrandom(); 134 lr &= (long) 0x00003fff; 135 r = (int) lr; 136 r = (r % ((y - x) + 1)) + x; 137 return(r); 138 } 139 140 int 141 rand_percent(percentage) 142 int percentage; 143 { 144 return(get_rand(1, 100) <= percentage); 145 } 146 147 int 148 coin_toss() 149 { 150 return(((rrandom() & 01) ? 1 : 0)); 151 } 152