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 (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* Copyright (c) 1988 AT&T */ 28 /* All Rights Reserved */ 29 30 /* 31 * drand48, etc. pseudo-random number generator 32 * This implementation assumes unsigned short integers of at least 33 * 16 bits, long integers of at least 32 bits, and ignores 34 * overflows on adding or multiplying two unsigned integers. 35 * Two's-complement representation is assumed in a few places. 36 * Some extra masking is done if unsigneds are exactly 16 bits 37 * or longs are exactly 32 bits, but so what? 38 * An assembly-language implementation would run significantly faster. 39 */ 40 /* 41 * New assumptions (supercede those stated above) for 64-bit work. 42 * Longs are now 64 bits, and we are bound by standards to return 43 * type long, hovever all internal calculations where long was 44 * previously used (32 bit precision) are now using the int32_t 45 * type (32 bit precision in both ILP32 and LP64 worlds). 46 */ 47 48 #include "lint.h" 49 #include <mtlib.h> 50 #include <synch.h> 51 #include <thread.h> 52 53 static mutex_t seed_lock = DEFAULTMUTEX; 54 55 #define EXPORT0(TYPE, fn, fnu) TYPE fn() { \ 56 TYPE res; \ 57 lmutex_lock(&seed_lock); \ 58 res = fnu(); \ 59 lmutex_unlock(&seed_lock); \ 60 return (res); } 61 #define EXPORT1(TYPE, fn, fnu) TYPE fn(unsigned short xsubi[3]) { \ 62 TYPE res; \ 63 lmutex_lock(&seed_lock); \ 64 res = fnu(xsubi); \ 65 lmutex_unlock(&seed_lock); \ 66 return (res); } 67 68 #define N 16 69 #define MASK ((unsigned)(1 << (N - 1)) + (1 << (N - 1)) - 1) 70 #define LOW(x) ((unsigned)(x) & MASK) 71 #define HIGH(x) LOW((x) >> N) 72 #define MUL(x, y, z) { int32_t l = (int32_t)(x) * (int32_t)(y); \ 73 (z)[0] = LOW(l); (z)[1] = HIGH(l); } 74 #define CARRY(x, y) ((int32_t)(x) + (int32_t)(y) > MASK) 75 #define ADDEQU(x, y, z) (z = CARRY(x, (y)), x = LOW(x + (y))) 76 #define X0 0x330E 77 #define X1 0xABCD 78 #define X2 0x1234 79 #define A0 0xE66D 80 #define A1 0xDEEC 81 #define A2 0x5 82 #define C 0xB 83 #define SET3(x, x0, x1, x2) ((x)[0] = (x0), (x)[1] = (x1), (x)[2] = (x2)) 84 #define SETLOW(x, y, n) SET3(x, LOW((y)[n]), LOW((y)[(n)+1]), LOW((y)[(n)+2])) 85 #define SEED(x0, x1, x2) (SET3(x, x0, x1, x2), SET3(a, A0, A1, A2), c = C) 86 #define REST(v) for (i = 0; i < 3; i++) { xsubi[i] = x[i]; x[i] = temp[i]; } \ 87 return (v) 88 #define NEST(TYPE, f, F) static TYPE f(unsigned short *xsubi) { \ 89 int i; TYPE v; unsigned temp[3]; \ 90 for (i = 0; i < 3; i++) { temp[i] = x[i]; x[i] = LOW(xsubi[i]); } \ 91 v = F(); REST(v); } 92 93 /* Way ugly solution to problem names, but it works */ 94 #define x _drand48_x 95 #define a _drand48_a 96 #define c _drand48_c 97 /* End way ugly */ 98 static unsigned x[3] = { X0, X1, X2 }, a[3] = { A0, A1, A2 }, c = C; 99 static unsigned short lastx[3]; 100 static void next(void); 101 102 static double 103 _drand48_u(void) 104 { 105 static double two16m = 1.0 / ((int32_t)1 << N); 106 107 next(); 108 return (two16m * (two16m * (two16m * x[0] + x[1]) + x[2])); 109 } 110 111 NEST(double, _erand48_u, _drand48_u) 112 113 static long 114 _lrand48_u(void) 115 { 116 next(); 117 return ((long)((int32_t)x[2] << (N - 1)) + (x[1] >> 1)); 118 } 119 120 static long 121 _mrand48_u(void) 122 { 123 next(); 124 return ((long)((int32_t)x[2] << N) + x[1]); 125 } 126 127 static void 128 next(void) 129 { 130 unsigned p[2], q[2], r[2], carry0, carry1; 131 132 MUL(a[0], x[0], p); 133 ADDEQU(p[0], c, carry0); 134 ADDEQU(p[1], carry0, carry1); 135 MUL(a[0], x[1], q); 136 ADDEQU(p[1], q[0], carry0); 137 MUL(a[1], x[0], r); 138 x[2] = LOW(carry0 + carry1 + CARRY(p[1], r[0]) + q[1] + r[1] + 139 a[0] * x[2] + a[1] * x[1] + a[2] * x[0]); 140 x[1] = LOW(p[1] + r[0]); 141 x[0] = LOW(p[0]); 142 } 143 144 void 145 srand48(long seedval) 146 { 147 int32_t fixseed = (int32_t)seedval; /* limit to 32 bits */ 148 149 lmutex_lock(&seed_lock); 150 SEED(X0, LOW(fixseed), HIGH(fixseed)); 151 lmutex_unlock(&seed_lock); 152 } 153 154 unsigned short * 155 seed48(unsigned short seed16v[3]) 156 { 157 lmutex_lock(&seed_lock); 158 SETLOW(lastx, x, 0); 159 SEED(LOW(seed16v[0]), LOW(seed16v[1]), LOW(seed16v[2])); 160 lmutex_unlock(&seed_lock); 161 return (lastx); 162 } 163 164 void 165 lcong48(unsigned short param[7]) 166 { 167 lmutex_lock(&seed_lock); 168 SETLOW(x, param, 0); 169 SETLOW(a, param, 3); 170 c = LOW(param[6]); 171 lmutex_unlock(&seed_lock); 172 } 173 174 NEST(long, _nrand48_u, _lrand48_u) 175 176 NEST(long, _jrand48_u, _mrand48_u) 177 178 EXPORT0(double, drand48, _drand48_u) 179 EXPORT1(double, erand48, _erand48_u) 180 181 EXPORT0(long, lrand48, _lrand48_u) 182 EXPORT1(long, nrand48, _nrand48_u) 183 184 EXPORT0(long, mrand48, _mrand48_u) 185 EXPORT1(long, jrand48, _jrand48_u) 186 187 #ifdef DRIVER 188 /* 189 * This should print the sequences of integers in Tables 2 190 * and 1 of the TM: 191 * 1623, 3442, 1447, 1829, 1305, ... 192 * 657EB7255101, D72A0C966378, 5A743C062A23, ... 193 */ 194 #include <stdio.h> 195 196 main() 197 { 198 int i; 199 200 for (i = 0; i < 80; i++) { 201 printf("%4d ", (int)(4096 * drand48())); 202 printf("%.4X%.4X%.4X\n", x[2], x[1], x[0]); 203 } 204 } 205 #endif 206