mirror of
https://review.haiku-os.org/buildtools
synced 2025-01-31 18:44:48 +01:00
66 lines
1.6 KiB
C
66 lines
1.6 KiB
C
|
/* __gmpfr_ceil_exp2 - returns y >= 2^d
|
||
|
|
|
||
|
|
Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2006, 2007 Free Software Foundation, Inc.
|
||
|
|
Contributed by the Arenaire and Cacao projects, INRIA.
|
||
|
|
|
||
|
|
This file is part of the MPFR Library.
|
||
|
|
|
||
|
|
The MPFR 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 MPFR 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 MPFR Library; see the file COPYING.LIB. If not, write to
|
||
|
|
the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
|
||
|
|
MA 02110-1301, USA. */
|
||
|
|
|
||
|
|
#include "mpfr-impl.h"
|
||
|
|
|
||
|
|
/* returns y >= 2^d, assuming that d <= 1024
|
||
|
|
for d integer, returns exactly 2^d
|
||
|
|
*/
|
||
|
|
double
|
||
|
|
__gmpfr_ceil_exp2 (double d)
|
||
|
|
{
|
||
|
|
long exp;
|
||
|
|
#if _GMP_IEEE_FLOATS
|
||
|
|
union ieee_double_extract x;
|
||
|
|
#else
|
||
|
|
struct {double d;} x;
|
||
|
|
#endif
|
||
|
|
|
||
|
|
MPFR_ASSERTN(d <= 1024.0);
|
||
|
|
exp = (long) d;
|
||
|
|
if (d != (double) exp)
|
||
|
|
exp++;
|
||
|
|
/* now exp = ceil(d) */
|
||
|
|
x.d = 1.0;
|
||
|
|
#if _GMP_IEEE_FLOATS
|
||
|
|
x.s.exp = exp <= -1022 ? 1 : 1023 + exp;
|
||
|
|
#else
|
||
|
|
if (exp >= 0)
|
||
|
|
{
|
||
|
|
while (exp != 0)
|
||
|
|
{
|
||
|
|
x.d *= 2.0;
|
||
|
|
exp--;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
while (exp != 0)
|
||
|
|
{
|
||
|
|
x.d *= (1.0 / 2.0);
|
||
|
|
exp++;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
return x.d;
|
||
|
|
}
|