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| author | Ulrich Drepper <drepper@gmail.com> | 2011-10-12 11:27:51 -0400 |
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| committer | Ulrich Drepper <drepper@gmail.com> | 2011-10-12 11:27:51 -0400 |
| commit | 0ac5ae2335292908f39031b1ea9fe8edce433c0f (patch) | |
| tree | f9d26c8abc0de39d18d4c13e70f6022cdc6b461f /math/w_log2.c | |
| parent | a843a204a3e8a0dd53584dad3668771abaec84ac (diff) | |
| download | glibc-0ac5ae2335292908f39031b1ea9fe8edce433c0f.tar.gz glibc-0ac5ae2335292908f39031b1ea9fe8edce433c0f.tar.xz glibc-0ac5ae2335292908f39031b1ea9fe8edce433c0f.zip | |
Optimize libm
libm is now somewhat integrated with gcc's -ffinite-math-only option and lots of the wrapper functions have been optimized.
Diffstat (limited to 'math/w_log2.c')
| -rw-r--r-- | math/w_log2.c | 49 |
1 files changed, 33 insertions, 16 deletions
diff --git a/math/w_log2.c b/math/w_log2.c index 90d2dff5d6..6d420438d4 100644 --- a/math/w_log2.c +++ b/math/w_log2.c @@ -1,29 +1,46 @@ -/* - * wrapper log2(X) - */ +/* Copyright (C) 2011 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper <drepper@gmail.com>, 2011. + 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, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <fenv.h> #include <math.h> #include <math_private.h> + +/* wrapper log2(x) */ double -__log2 (double x) /* wrapper log2 */ +__log2 (double x) { -#ifdef _IEEE_LIBM - return __ieee754_log2 (x); -#else - double z; - z = __ieee754_log2 (x); - if (_LIB_VERSION == _IEEE_ || __isnan (x)) return z; - if (x <= 0.0) + if (__builtin_expect (x <= 0.0, 0) && _LIB_VERSION != _IEEE_) { if (x == 0.0) - return __kernel_standard (x, x, 48); /* log2 (0) */ + { + feraiseexcept (FE_DIVBYZERO); + return __kernel_standard (x, x, 48); /* log2(0) */ + } else - return __kernel_standard (x, x, 49); /* log2 (x < 0) */ + { + feraiseexcept (FE_INVALID); + return __kernel_standard (x, x, 49); /* log2(x<0) */ + } } - else - return z; -#endif + + return __ieee754_log2 (x); } weak_alias (__log2, log2) #ifdef NO_LONG_DOUBLE |