1/* Copyright (C) 1995, 1997, 2001 Free Software Foundation, Inc.
2   This file is part of the GNU C Library.
3   Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, August 1995.
4
5   The GNU C Library is free software; you can redistribute it and/or
6   modify it under the terms of the GNU Lesser General Public
7   License as published by the Free Software Foundation; either
8   version 2.1 of the License, or (at your option) any later version.
9
10   The GNU C Library is distributed in the hope that it will be useful,
11   but WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13   Lesser General Public License for more details.
14
15   You should have received a copy of the GNU Lesser General Public
16   License along with the GNU C Library; if not, write to the Free
17   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
18   02111-1307 USA.  */
19
20#include <ieee754.h>
21#include <stdlib.h>
22#include <limits.h>
23
24
25int
26__erand48_r (xsubi, buffer, result)
27     unsigned short int xsubi[3];
28     struct drand48_data *buffer;
29     double *result;
30{
31  union ieee754_double temp;
32
33  /* Compute next state.  */
34  if (__drand48_iterate (xsubi, buffer) < 0)
35    return -1;
36
37  /* Construct a positive double with the 48 random bits distributed over
38     its fractional part so the resulting FP number is [0.0,1.0).  */
39
40  temp.ieee.negative = 0;
41  temp.ieee.exponent = IEEE754_DOUBLE_BIAS;
42  temp.ieee.mantissa0 = (xsubi[2] << 4) | (xsubi[1] >> 12);
43  temp.ieee.mantissa1 = ((xsubi[1] & 0xfff) << 20) | (xsubi[0] << 4);
44
45  /* Please note the lower 4 bits of mantissa1 are always 0.  */
46  *result = temp.d - 1.0;
47
48  return 0;
49}
50weak_alias (__erand48_r, erand48_r)
51