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 #pragma ident "%Z%%M% %I% %E% SMI" 31 32 /* 33 * drand48, etc. pseudo-random number generator 34 * This implementation assumes unsigned short integers of at least 35 * 16 bits, long integers of at least 32 bits, and ignores 36 * overflows on adding or multiplying two unsigned integers. 37 * Two's-complement representation is assumed in a few places. 38 * Some extra masking is done if unsigneds are exactly 16 bits 39 * or longs are exactly 32 bits, but so what? 40 * An assembly-language implementation would run significantly faster. 41 */ 42 /* 43 * New assumptions (supercede those stated above) for 64-bit work. 44 * Longs are now 64 bits, and we are bound by standards to return 45 * type long, hovever all internal calculations where long was 46 * previously used (32 bit precision) are now using the int32_t 47 * type (32 bit precision in both ILP32 and LP64 worlds). 48 */ 49 50 #include <sys/mutex.h> 51 52 static kmutex_t seed_lock; 53 static int init48done = 0; 54 55 #define EXPORT0(TYPE, fn, fnu) TYPE fn() { \ 56 TYPE res; \ 57 mutex_enter(&seed_lock); \ 58 res = fnu(); \ 59 mutex_exit(&seed_lock); \ 60 return (res); } 61 #define EXPORT1(TYPE, fn, fnu) TYPE fn(unsigned short xsubi[3]) { \ 62 TYPE res; \ 63 mutex_enter(&seed_lock); \ 64 res = fnu(xsubi); \ 65 mutex_exit(&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 ipf_r_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, ipf_r_erand48_u, ipf_r_drand48_u) 112 113 static long 114 ipf_r_lrand48_u(void) 115 { 116 next(); 117 return ((long)((int32_t)x[2] << (N - 1)) + (x[1] >> 1)); 118 } 119 120 static void 121 init48(void) 122 { 123 mutex_init(&seed_lock, 0L, MUTEX_DRIVER, 0L); 124 init48done = 1; 125 } 126 127 static long 128 ipf_r_mrand48_u(void) 129 { 130 next(); 131 return ((long)((int32_t)x[2] << N) + x[1]); 132 } 133 134 static void 135 next(void) 136 { 137 unsigned p[2], q[2], r[2], carry0, carry1; 138 139 MUL(a[0], x[0], p); 140 ADDEQU(p[0], c, carry0); 141 ADDEQU(p[1], carry0, carry1); 142 MUL(a[0], x[1], q); 143 ADDEQU(p[1], q[0], carry0); 144 MUL(a[1], x[0], r); 145 x[2] = LOW(carry0 + carry1 + CARRY(p[1], r[0]) + q[1] + r[1] + 146 a[0] * x[2] + a[1] * x[1] + a[2] * x[0]); 147 x[1] = LOW(p[1] + r[0]); 148 x[0] = LOW(p[0]); 149 } 150 151 void 152 ipf_r_srand48(long seedval) 153 { 154 int32_t fixseed = (int32_t)seedval; /* limit to 32 bits */ 155 156 if (init48done == 0) 157 init48(); 158 mutex_enter(&seed_lock); 159 SEED(X0, LOW(fixseed), HIGH(fixseed)); 160 mutex_exit(&seed_lock); 161 } 162 163 unsigned short * 164 ipf_r_seed48(unsigned short seed16v[3]) 165 { 166 if (init48done == 0) 167 init48(); 168 mutex_enter(&seed_lock); 169 SETLOW(lastx, x, 0); 170 SEED(LOW(seed16v[0]), LOW(seed16v[1]), LOW(seed16v[2])); 171 mutex_exit(&seed_lock); 172 return (lastx); 173 } 174 175 void 176 ipf_r_lcong48(unsigned short param[7]) 177 { 178 if (init48done == 0) 179 init48(); 180 mutex_enter(&seed_lock); 181 SETLOW(x, param, 0); 182 SETLOW(a, param, 3); 183 c = LOW(param[6]); 184 mutex_exit(&seed_lock); 185 } 186 187 NEST(long, ipf_r_nrand48_u, ipf_r_lrand48_u) 188 189 NEST(long, ipf_r_jrand48_u, ipf_r_mrand48_u) 190 191 EXPORT0(double, ipf_r_drand48, ipf_r_drand48_u) 192 EXPORT1(double, ipf_r_erand48, ipf_r_erand48_u) 193 194 EXPORT0(long, ipf_r_lrand48, ipf_r_lrand48_u) 195 EXPORT1(long, ipf_r_nrand48, ipf_r_nrand48_u) 196 197 EXPORT0(long, ipf_r_mrand48, ipf_r_mrand48_u) 198 EXPORT1(long, ipf_r_jrand48, ipf_r_jrand48_u) 199 200 #ifdef DRIVER 201 /* 202 This should print the sequences of integers in Tables 2 203 and 1 of the TM: 204 1623, 3442, 1447, 1829, 1305, ... 205 657EB7255101, D72A0C966378, 5A743C062A23, ... 206 */ 207 #include <stdio.h> 208 209 main() 210 { 211 int i; 212 213 for (i = 0; i < 80; i++) { 214 printf("%4d ", (int)(4096 * ipf_r_drand48())); 215 printf("%.4X%.4X%.4X\n", x[2], x[1], x[0]); 216 } 217 } 218 #else 219 220 #include <sys/random.h> 221 222 unsigned 223 ipf_random() 224 { 225 static int seeded = 0; 226 227 if (seeded == 0) { 228 long seed; 229 230 /* 231 * Keep reseeding until some good randomness comes from the 232 * kernel. One of two things will happen: it will succeed or 233 * it will fail (with poor randomness), thus creating NAT 234 * sessions will be "slow" until enough randomness is gained 235 * to not need to get more. It isn't necessary to initialise 236 * seed as it will just pickup whatever random garbage has 237 * been left on the heap and that's good enough until we 238 * get some good garbage. 239 */ 240 if (random_get_bytes((uint8_t *)&seed, sizeof (seed)) == 0) 241 seeded = 1; 242 ipf_r_srand48(seed); 243 } 244 245 return (unsigned)ipf_r_lrand48(); 246 } 247 #endif 248