1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 1996 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* Copyright (c) 1984 AT&T */ 28 /* All Rights Reserved */ 29 30 #pragma ident "%Z%%M% %I% %E% SMI" 31 32 /*LINTLIBRARY*/ 33 /* 34 * drand48, etc. pseudo-random number generator 35 * This implementation assumes unsigned short integers of at least 36 * 16 bits, long integers of at least 32 bits, and ignores 37 * overflows on adding or multiplying two unsigned integers. 38 * Two's-complement representation is assumed in a few places. 39 * Some extra masking is done if unsigneds are exactly 16 bits 40 * or longs are exactly 32 bits, but so what? 41 * An assembly-language implementation would run significantly faster. 42 */ 43 #define N 16 44 #define MASK ((unsigned)(1 << (N - 1)) + (1 << (N - 1)) - 1) 45 #define LOW(x) ((unsigned)(x) & MASK) 46 #define HIGH(x) LOW((x) >> N) 47 #define MUL(x, y, z) { long l = (long)(x) * (long)(y); \ 48 (z)[0] = LOW(l); (z)[1] = HIGH(l); } 49 #define CARRY(x, y) ((long)(x) + (long)(y) > MASK) 50 #define ADDEQU(x, y, z) (z = CARRY(x, (y)), x = LOW(x + (y))) 51 #define X0 0x330E 52 #define X1 0xABCD 53 #define X2 0x1234 54 #define A0 0xE66D 55 #define A1 0xDEEC 56 #define A2 0x5 57 #define C 0xB 58 #define SET3(x, x0, x1, x2) ((x)[0] = (x0), (x)[1] = (x1), (x)[2] = (x2)) 59 #define SETLOW(x, y, n) SET3(x, LOW((y)[n]), LOW((y)[(n)+1]), LOW((y)[(n)+2])) 60 #define SEED(x0, x1, x2) (SET3(x, x0, x1, x2), SET3(a, A0, A1, A2), c = C) 61 #define REST(v) \ 62 for (i = 0; i < 3; i++) { \ 63 xsubi[i] = x[i]; \ 64 x[i] = temp[i]; \ 65 } \ 66 return (v) 67 68 #define NEST(TYPE, f, F) \ 69 TYPE f(xsubi) \ 70 register unsigned short *xsubi; \ 71 { \ 72 register int i; \ 73 register TYPE v; \ 74 unsigned temp[3]; \ 75 \ 76 for (i = 0; i < 3; i++) { \ 77 temp[i] = x[i]; \ 78 x[i] = LOW(xsubi[i]); \ 79 } \ 80 v = F(); \ 81 REST(v); \ 82 } 83 84 static unsigned x[3] = { X0, X1, X2 }, a[3] = { A0, A1, A2 }, c = C; 85 static unsigned short lastx[3]; 86 static void next(); 87 88 double 89 drand48() 90 { 91 static double two16m = 1.0 / (1L << N); 92 93 next(); 94 return (two16m * (two16m * (two16m * x[0] + x[1]) + x[2])); 95 } 96 97 NEST(double, erand48, drand48) 98 99 long 100 lrand48() 101 { 102 next(); 103 return (((long)x[2] << (N - 1)) + (x[1] >> 1)); 104 } 105 106 long 107 mrand48() 108 { 109 next(); 110 return (((long)x[2] << N) + x[1]); 111 } 112 113 static void 114 next() 115 { 116 unsigned p[2], q[2], r[2], carry0, carry1; 117 118 MUL(a[0], x[0], p); 119 ADDEQU(p[0], c, carry0); 120 ADDEQU(p[1], carry0, carry1); 121 MUL(a[0], x[1], q); 122 ADDEQU(p[1], q[0], carry0); 123 MUL(a[1], x[0], r); 124 x[2] = LOW(carry0 + carry1 + CARRY(p[1], r[0]) + q[1] + r[1] + 125 a[0] * x[2] + a[1] * x[1] + a[2] * x[0]); 126 x[1] = LOW(p[1] + r[0]); 127 x[0] = LOW(p[0]); 128 } 129 130 void 131 srand48(seedval) 132 long seedval; 133 { 134 SEED(X0, LOW(seedval), HIGH(seedval)); 135 } 136 137 unsigned short * 138 seed48(seed16v) 139 unsigned short seed16v[3]; 140 { 141 SETLOW(lastx, x, 0); 142 SEED(LOW(seed16v[0]), LOW(seed16v[1]), LOW(seed16v[2])); 143 return (lastx); 144 } 145 146 void 147 lcong48(param) 148 unsigned short param[7]; 149 { 150 SETLOW(x, param, 0); 151 SETLOW(a, param, 3); 152 c = LOW(param[6]); 153 } 154 155 NEST(long, nrand48, lrand48) 156 157 NEST(long, jrand48, mrand48) 158 159 #ifdef DRIVER 160 /* 161 * This should print the sequences of integers in Tables 2 162 * and 1 of the TM: 163 * 1623, 3442, 1447, 1829, 1305, ... 164 * 657EB7255101, D72A0C966378, 5A743C062A23, ... 165 */ 166 #include <stdio.h> 167 168 main() 169 { 170 int i; 171 172 for (i = 0; i < 80; i++) { 173 printf("%4d ", (int)(4096 * drand48())); 174 printf("%.4X%.4X%.4X\n", x[2], x[1], x[0]); 175 } 176 } 177 #endif 178