Add --enable-static-pie configure option to build static PIE [BZ #19574]
[glibc.git] / math / e_exp2_template.c
blobf1b34882d25c78aac4bea140eb91ace895c79b32
1 /* Compute 2^x.
2 Copyright (C) 2012-2017 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
19 #include <math.h>
20 #include <math_private.h>
21 #include <float.h>
23 #define declare_mgen_finite_alias_x(from, to) \
24 strong_alias (from, to ## _finite)
25 #define declare_mgen_finite_alias_s(from,to) \
26 declare_mgen_finite_alias_x (from, to)
27 #define declare_mgen_finite_alias(from, to) \
28 declare_mgen_finite_alias_s (M_SUF (from), M_SUF (to))
30 FLOAT
31 M_DECL_FUNC (__ieee754_exp2) (FLOAT x)
33 if (__glibc_likely (isless (x, (FLOAT) M_MAX_EXP)))
35 if (__builtin_expect (isgreaterequal (x, (FLOAT) (M_MIN_EXP - M_MANT_DIG
36 - 1)), 1))
38 int intx = (int) x;
39 FLOAT fractx = x - intx;
40 FLOAT result;
41 if (M_FABS (fractx) < M_EPSILON / 4)
42 result = M_SCALBN (1 + fractx, intx);
43 else
44 result = M_SCALBN (M_EXP (M_SUF (M_LN2) * fractx), intx);
45 math_check_force_underflow_nonneg (result);
46 return result;
48 else
50 /* Underflow or exact zero. */
51 if (isinf (x))
52 return 0;
53 else
54 return M_MIN * M_MIN;
57 else
58 /* Infinity, NaN or overflow. */
59 return M_MAX * x;
61 declare_mgen_finite_alias (__ieee754_exp2, __exp2)