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49 lines
1.4 KiB
C
49 lines
1.4 KiB
C
/* Copyright (C) 2011, 2012 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <fenv.h>
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#include <math.h>
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#include <math_private.h>
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/* wrapper log2(x) */
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double
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__log2 (double x)
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{
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if (__builtin_expect (islessequal (x, 0.0), 0) && _LIB_VERSION != _IEEE_)
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{
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if (x == 0.0)
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{
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feraiseexcept (FE_DIVBYZERO);
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return __kernel_standard (x, x, 48); /* log2(0) */
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}
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else
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{
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feraiseexcept (FE_INVALID);
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return __kernel_standard (x, x, 49); /* log2(x<0) */
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}
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}
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return __ieee754_log2 (x);
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}
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weak_alias (__log2, log2)
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#ifdef NO_LONG_DOUBLE
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strong_alias (__log2, __log2l)
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weak_alias (__log2, log2l)
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#endif
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