1 /* Copyright (C) 2011-2022 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18 #include <fenv.h>
19 #include <math.h>
20 #include <math_private.h>
21 #include <math-svid-compat.h>
22 #include <libm-alias-double.h>
23
24
25 #if LIBM_SVID_COMPAT && (SHLIB_COMPAT (libm, GLIBC_2_1, GLIBC_2_29) \
26 || defined NO_LONG_DOUBLE \
27 || defined LONG_DOUBLE_COMPAT)
28 /* wrapper log2(x) */
29 double
__log2_compat(double x)30 __log2_compat (double x)
31 {
32 if (__builtin_expect (islessequal (x, 0.0), 0) && _LIB_VERSION != _IEEE_)
33 {
34 if (x == 0.0)
35 {
36 feraiseexcept (FE_DIVBYZERO);
37 return __kernel_standard (x, x, 48); /* log2(0) */
38 }
39 else
40 {
41 feraiseexcept (FE_INVALID);
42 return __kernel_standard (x, x, 49); /* log2(x<0) */
43 }
44 }
45
46 return __ieee754_log2 (x);
47 }
48 # if SHLIB_COMPAT (libm, GLIBC_2_1, GLIBC_2_29)
49 compat_symbol (libm, __log2_compat, log2, GLIBC_2_1);
50 # endif
51 # ifdef NO_LONG_DOUBLE
52 weak_alias (__log2_compat, log2l)
53 # endif
54 # ifdef LONG_DOUBLE_COMPAT
55 /* Work around gas bug "multiple versions for symbol". */
56 weak_alias (__log2_compat, __log2_compat_alias)
57
58 LONG_DOUBLE_COMPAT_CHOOSE_libm_log2l (
59 compat_symbol (libm, __log2_compat_alias, log2l, FIRST_VERSION_libm_log2l), );
60 # endif
61 #endif
62