From 94e5ab630be58fa6d008fbfa735492bd6ce2a568 Mon Sep 17 00:00:00 2001 From: Eric Andersen Date: Wed, 13 Mar 2002 23:38:40 +0000 Subject: Merge in an ugly pile of rand* functions from glibc. :( --- libc/stdlib/erand48_r.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) create mode 100644 libc/stdlib/erand48_r.c (limited to 'libc/stdlib/erand48_r.c') diff --git a/libc/stdlib/erand48_r.c b/libc/stdlib/erand48_r.c new file mode 100644 index 000000000..fb48304fa --- /dev/null +++ b/libc/stdlib/erand48_r.c @@ -0,0 +1,48 @@ +/* Copyright (C) 1995, 1997, 2001 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper >, August 1995. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include +#include +#include + + +int erand48_r (xsubi, buffer, result) + unsigned short int xsubi[3]; + struct drand48_data *buffer; + double *result; +{ + union ieee754_double temp; + + /* Compute next state. */ + if (__drand48_iterate (xsubi, buffer) < 0) + return -1; + + /* Construct a positive double with the 48 random bits distributed over + its fractional part so the resulting FP number is [0.0,1.0). */ + + temp.ieee.negative = 0; + temp.ieee.exponent = IEEE754_DOUBLE_BIAS; + temp.ieee.mantissa0 = (xsubi[2] << 4) | (xsubi[1] >> 12); + temp.ieee.mantissa1 = ((xsubi[1] & 0xfff) << 20) | (xsubi[0] << 4); + + /* Please note the lower 4 bits of mantissa1 are always 0. */ + *result = temp.d - 1.0; + + return 0; +} -- cgit v1.2.3