diff options
Diffstat (limited to 'usr/src/lib/libbc/libc/gen/common/drand48.c')
| -rw-r--r-- | usr/src/lib/libbc/libc/gen/common/drand48.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/usr/src/lib/libbc/libc/gen/common/drand48.c b/usr/src/lib/libbc/libc/gen/common/drand48.c new file mode 100644 index 0000000000..13d0895991 --- /dev/null +++ b/usr/src/lib/libbc/libc/gen/common/drand48.c @@ -0,0 +1,177 @@ +/* + * CDDL HEADER START + * + * The contents of this file are subject to the terms of the + * Common Development and Distribution License, Version 1.0 only + * (the "License"). You may not use this file except in compliance + * with the License. + * + * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE + * or http://www.opensolaris.org/os/licensing. + * See the License for the specific language governing permissions + * and limitations under the License. + * + * When distributing Covered Code, include this CDDL HEADER in each + * file and include the License file at usr/src/OPENSOLARIS.LICENSE. + * If applicable, add the following below this CDDL HEADER, with the + * fields enclosed by brackets "[]" replaced with your own identifying + * information: Portions Copyright [yyyy] [name of copyright owner] + * + * CDDL HEADER END + */ +/* + * Copyright 1996 Sun Microsystems, Inc. All rights reserved. + * Use is subject to license terms. + */ + +/* Copyright (c) 1984 AT&T */ +/* All Rights Reserved */ + +#pragma ident "%Z%%M% %I% %E% SMI" + +/*LINTLIBRARY*/ +/* + * drand48, etc. pseudo-random number generator + * This implementation assumes unsigned short integers of at least + * 16 bits, long integers of at least 32 bits, and ignores + * overflows on adding or multiplying two unsigned integers. + * Two's-complement representation is assumed in a few places. + * Some extra masking is done if unsigneds are exactly 16 bits + * or longs are exactly 32 bits, but so what? + * An assembly-language implementation would run significantly faster. + */ +#define N 16 +#define MASK ((unsigned)(1 << (N - 1)) + (1 << (N - 1)) - 1) +#define LOW(x) ((unsigned)(x) & MASK) +#define HIGH(x) LOW((x) >> N) +#define MUL(x, y, z) { long l = (long)(x) * (long)(y); \ + (z)[0] = LOW(l); (z)[1] = HIGH(l); } +#define CARRY(x, y) ((long)(x) + (long)(y) > MASK) +#define ADDEQU(x, y, z) (z = CARRY(x, (y)), x = LOW(x + (y))) +#define X0 0x330E +#define X1 0xABCD +#define X2 0x1234 +#define A0 0xE66D +#define A1 0xDEEC +#define A2 0x5 +#define C 0xB +#define SET3(x, x0, x1, x2) ((x)[0] = (x0), (x)[1] = (x1), (x)[2] = (x2)) +#define SETLOW(x, y, n) SET3(x, LOW((y)[n]), LOW((y)[(n)+1]), LOW((y)[(n)+2])) +#define SEED(x0, x1, x2) (SET3(x, x0, x1, x2), SET3(a, A0, A1, A2), c = C) +#define REST(v) \ + for (i = 0; i < 3; i++) { \ + xsubi[i] = x[i]; \ + x[i] = temp[i]; \ + } \ + return (v) + +#define NEST(TYPE, f, F) \ + TYPE f(xsubi) \ + register unsigned short *xsubi; \ + { \ + register int i; \ + register TYPE v; \ + unsigned temp[3]; \ + \ + for (i = 0; i < 3; i++) { \ + temp[i] = x[i]; \ + x[i] = LOW(xsubi[i]); \ + } \ + v = F(); \ + REST(v); \ + } + +static unsigned x[3] = { X0, X1, X2 }, a[3] = { A0, A1, A2 }, c = C; +static unsigned short lastx[3]; +static void next(); + +double +drand48() +{ + static double two16m = 1.0 / (1L << N); + + next(); + return (two16m * (two16m * (two16m * x[0] + x[1]) + x[2])); +} + +NEST(double, erand48, drand48) + +long +lrand48() +{ + next(); + return (((long)x[2] << (N - 1)) + (x[1] >> 1)); +} + +long +mrand48() +{ + next(); + return (((long)x[2] << N) + x[1]); +} + +static void +next() +{ + unsigned p[2], q[2], r[2], carry0, carry1; + + MUL(a[0], x[0], p); + ADDEQU(p[0], c, carry0); + ADDEQU(p[1], carry0, carry1); + MUL(a[0], x[1], q); + ADDEQU(p[1], q[0], carry0); + MUL(a[1], x[0], r); + x[2] = LOW(carry0 + carry1 + CARRY(p[1], r[0]) + q[1] + r[1] + + a[0] * x[2] + a[1] * x[1] + a[2] * x[0]); + x[1] = LOW(p[1] + r[0]); + x[0] = LOW(p[0]); +} + +void +srand48(seedval) +long seedval; +{ + SEED(X0, LOW(seedval), HIGH(seedval)); +} + +unsigned short * +seed48(seed16v) +unsigned short seed16v[3]; +{ + SETLOW(lastx, x, 0); + SEED(LOW(seed16v[0]), LOW(seed16v[1]), LOW(seed16v[2])); + return (lastx); +} + +void +lcong48(param) +unsigned short param[7]; +{ + SETLOW(x, param, 0); + SETLOW(a, param, 3); + c = LOW(param[6]); +} + +NEST(long, nrand48, lrand48) + +NEST(long, jrand48, mrand48) + +#ifdef DRIVER +/* + * This should print the sequences of integers in Tables 2 + * and 1 of the TM: + * 1623, 3442, 1447, 1829, 1305, ... + * 657EB7255101, D72A0C966378, 5A743C062A23, ... + */ +#include <stdio.h> + +main() +{ + int i; + + for (i = 0; i < 80; i++) { + printf("%4d ", (int)(4096 * drand48())); + printf("%.4X%.4X%.4X\n", x[2], x[1], x[0]); + } +} +#endif |