/* Compute 2^x.
Copyright (C) 2012-2018 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 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, see
<
http://www.gnu.org/licenses/>. */
#include "quadmath-imp.h"
__float128
exp2q (__float128 x)
{
if (__glibc_likely (__builtin_isless (x, (__float128) FLT128_MAX_EXP)))
{
if (__builtin_expect (__builtin_isgreaterequal (x, (__float128) (FLT128_MIN_EXP - FLT128_MANT_DIG
- 1)), 1))
{
int intx = (int) x;
__float128 fractx = x - intx;
__float128 result;
if (fabsq (fractx) < FLT128_EPSILON / 4)
result = scalbnq (1 + fractx, intx);
else
result = scalbnq (expq (M_LN2q * fractx), intx);
math_check_force_underflow_nonneg (result);
return result;
}
else
{
/* Underflow or exact zero. */
if (isinfq (x))
return 0;
else
return FLT128_MIN * FLT128_MIN;
}
}
else
/* Infinity, NaN or overflow. */
return FLT128_MAX * x;
}
