4699cb8b5f
This patch makes dbl-64 logb use libm_alias_double. Both the dbl-64 and dbl-64/wordsize-64 versions are changed, and the ldbl-opt version is removed. Because of multiarch wrappers, the changed implementations are made not to define aliases at all if __logb is defined as a macro, as with other functions, so avoiding duplicate compat symbols while allowing those wrappers to be simplified. Tested for x86_64, and verified with build-many-glibcs.py that installed stripped shared libraries are unchanged (except on alpha where changes from using the wordsize-64 version are expected). * sysdeps/ieee754/dbl-64/s_logb.c: Include <libm-alias-double.h>. (logb): Define using libm_alias_double, only if [!__logb]. * sysdeps/ieee754/dbl-64/wordsize-64/s_logb.c: Include <libm-alias-double.h>. (logb): Define using libm_alias_double, only if [!__logb]. * sysdeps/ieee754/ldbl-opt/s_logb.c: Remove file. * sysdeps/powerpc/powerpc32/power4/fpu/multiarch/s_logb-ppc32.c (weak_alias): Do not undefine and redefine. (strong_alias): Likewise. * sysdeps/powerpc/powerpc64/fpu/multiarch/s_logb-ppc64.c (weak_alias): Likewise. (strong_alias): Likewise.
48 lines
1.3 KiB
C
48 lines
1.3 KiB
C
/* Compute radix independent exponent.
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Copyright (C) 2011-2017 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 <math.h>
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#include <math_private.h>
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#include <libm-alias-double.h>
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double
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__logb (double x)
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{
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int64_t ix, ex;
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EXTRACT_WORDS64 (ix, x);
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ix &= UINT64_C(0x7fffffffffffffff);
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if (ix == 0)
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return -1.0 / fabs (x);
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ex = ix >> 52;
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if (ex == 0x7ff)
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return x * x;
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if (__glibc_unlikely (ex == 0))
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{
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int m = __builtin_clzll (ix);
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ex -= m - 12;
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}
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return (double) (ex - 1023);
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}
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#ifndef __logb
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libm_alias_double (__logb, logb)
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#endif
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