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/* Copyright (C) 1991, 1992 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <ansidecl.h>
#include <errno.h>
#include <math.h>
extern double EXFUN(__logb, (double x));
/* Break VALUE into a normalized fraction and an integral power of 2. */
double
DEFUN(frexp, (value, exp), double value AND int *exp)
{
#ifdef NAN
if (__isinf (value))
{
errno = EDOM;
*exp = 0;
return __copysign (NAN, value);
}
#endif
if (__isnan (value))
{
errno = EDOM;
*exp = 0;
return value;
}
if (value == 0)
{
*exp = 0;
return value;
}
/* Add one to the exponent of the number,
so we have one digit before the binary point. */
*exp = (int) __logb (value) + 1;
return ldexp (value, - *exp);
}
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