diff options
Diffstat (limited to 'libm/w_exp2.c')
| -rw-r--r-- | libm/w_exp2.c | 45 |
1 files changed, 32 insertions, 13 deletions
diff --git a/libm/w_exp2.c b/libm/w_exp2.c index e00277abf..1215c2e92 100644 --- a/libm/w_exp2.c +++ b/libm/w_exp2.c @@ -1,19 +1,38 @@ -/* - * ==================================================== - * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. - * - * Developed at SunPro, a Sun Microsystems, Inc. business. - * Permission to use, copy, modify, and distribute this - * software is freely granted, provided that this notice - * is preserved. - * ==================================================== - */ +/* Copyright (C) 2011-2016 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper <drepper@gmail.com>, 2011. -#include "math.h" + 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 <math.h> #include "math_private.h" -double exp2(double x) +/* wrapper exp2(x) */ +double +exp2 (double x) { - return pow(2.0, x); +#if __UCLIBC_HAS_FENV__ + double z = pow(2.0, x); + if (__builtin_expect (!isfinite (z) || z == 0, 0) + && isfinite (x) && _LIB_VERSION != _IEEE_) + /* exp2 overflow: 44, exp2 underflow: 45 */ + return __kernel_standard (x, x, 44 + !!signbit (x)); + + return z; +#else + return pow(2.0, x); +#endif } libm_hidden_def(exp2) |