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/* Copyright (C) 1995, 1997 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, August 1995.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <ieee754.h>
#include <stdlib.h>
#include <limits.h>
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). */
#if USHRT_MAX == 65535
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);
#elif USHRT_MAX == 2147483647
temp.ieee.negative = 0;
temp.ieee.exponent = IEEE754_DOUBLE_BIAS;
temp.ieee.mantissa0 = (xsubi[1] << 4) | (xsubi[0] >> 28);
temp.ieee.mantissa1 = ((xsubi[0] & 0xfffffff) << 4);
#else
# error Unsupported size of short int
#endif
/* Please note the lower 4 bits of mantissa1 are always 0. */
*result = temp.d - 1.0;
return 0;
}
weak_alias (__erand48_r, erand48_r)
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