2018-05-30 04:52:24 +08:00
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/* Multiply by integral power of radix.
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2021-01-03 03:32:25 +08:00
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Copyright (C) 2011-2021 Free Software Foundation, Inc.
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2018-05-30 04:52:24 +08:00
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2011-10-12 23:27:51 +08:00
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This file is part of the GNU C Library.
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1996-03-06 05:41:30 +08:00
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2011-10-12 23:27:51 +08:00
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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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1996-03-06 05:41:30 +08:00
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2011-10-12 23:27:51 +08:00
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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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2012-02-10 07:18:22 +08:00
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License along with the GNU C Library; if not, see
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Prefer https to http for gnu.org and fsf.org URLs
Also, change sources.redhat.com to sourceware.org.
This patch was automatically generated by running the following shell
script, which uses GNU sed, and which avoids modifying files imported
from upstream:
sed -ri '
s,(http|ftp)(://(.*\.)?(gnu|fsf|sourceware)\.org($|[^.]|\.[^a-z])),https\2,g
s,(http|ftp)(://(.*\.)?)sources\.redhat\.com($|[^.]|\.[^a-z]),https\2sourceware.org\4,g
' \
$(find $(git ls-files) -prune -type f \
! -name '*.po' \
! -name 'ChangeLog*' \
! -path COPYING ! -path COPYING.LIB \
! -path manual/fdl-1.3.texi ! -path manual/lgpl-2.1.texi \
! -path manual/texinfo.tex ! -path scripts/config.guess \
! -path scripts/config.sub ! -path scripts/install-sh \
! -path scripts/mkinstalldirs ! -path scripts/move-if-change \
! -path INSTALL ! -path locale/programs/charmap-kw.h \
! -path po/libc.pot ! -path sysdeps/gnu/errlist.c \
! '(' -name configure \
-execdir test -f configure.ac -o -f configure.in ';' ')' \
! '(' -name preconfigure \
-execdir test -f preconfigure.ac ';' ')' \
-print)
and then by running 'make dist-prepare' to regenerate files built
from the altered files, and then executing the following to cleanup:
chmod a+x sysdeps/unix/sysv/linux/riscv/configure
# Omit irrelevant whitespace and comment-only changes,
# perhaps from a slightly-different Autoconf version.
git checkout -f \
sysdeps/csky/configure \
sysdeps/hppa/configure \
sysdeps/riscv/configure \
sysdeps/unix/sysv/linux/csky/configure
# Omit changes that caused a pre-commit check to fail like this:
# remote: *** error: sysdeps/powerpc/powerpc64/ppc-mcount.S: trailing lines
git checkout -f \
sysdeps/powerpc/powerpc64/ppc-mcount.S \
sysdeps/unix/sysv/linux/s390/s390-64/syscall.S
# Omit change that caused a pre-commit check to fail like this:
# remote: *** error: sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S: last line does not end in newline
git checkout -f sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S
2019-09-07 13:40:42 +08:00
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<https://www.gnu.org/licenses/>. */
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1996-03-06 05:41:30 +08:00
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2005-12-14 23:06:39 +08:00
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#include <math.h>
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2011-10-08 17:16:04 +08:00
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#include <math_private.h>
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2019-07-16 23:17:22 +08:00
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#include <libm-alias-finite.h>
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2011-10-12 23:27:51 +08:00
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2018-05-30 04:52:24 +08:00
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static FLOAT
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2011-10-12 23:27:51 +08:00
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__attribute__ ((noinline))
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2018-05-30 04:52:24 +08:00
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invalid_fn (FLOAT x, FLOAT fn)
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1996-03-06 05:41:30 +08:00
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{
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2018-05-30 04:52:24 +08:00
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if (M_SUF (rint) (fn) != fn)
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Do not call __nan in scalb functions.
When libm functions return a NaN: if it is for NaN input, it should be
computed from that input (e.g. adding it to itself), so that payloads
are propagated and signaling NaNs quieted, while if it is for non-NaN
input, it should be produced by a computation such as
(x - x) / (x - x), which raises "invalid" at the same time as
producing an appropriate NaN, so avoiding any need for a call to
feraiseexcept.
Various libm functions, however, call __nan ("") (or __nanf or __nanl)
to determine the NaN to return, together with using feraiseexcept
(FE_INVALID) to raise the exception. sysdeps/generic/math_private.h
has an optimization for those functions with constant "" argument so
this doesn't actually involve a call to the __nan function, but it is
still not the preferred approach for producing NaNs. (The optimized
code also always uses the NAN macro, i.e. produces a default NaN for
float converted to whatever the target type is, and on some
architectures that may not be the same as the preferred default NaN
for double or long double.)
This patch fixes the scalb functions to use the conventional method of
generating NaNs and raising "invalid" with an appropriate
computation. (Most instances of this issue are in the complex
functions, where it can more readily be fixed once they have been made
type-generic and so only a third as many places need fixing. Some of
the complex functions use __nan ("") + __nan (""), where the addition
serves no purpose whatsoever.)
Tested for x86_64 and x86.
* math/e_scalb.c: Do not include <fenv.h>.
(invalid_fn): Do calculation resulting in NaN instead of raising
FE_INVALID and returning a NaN explicitly.
* math/e_scalbf.c: Do not include <fenv.h>.
(invalid_fn): Do calculation resulting in NaN instead of raising
FE_INVALID and returning a NaN explicitly.
* math/e_scalbl.c: Do not include <fenv.h>.
(invalid_fn): Do calculation resulting in NaN instead of raising
FE_INVALID and returning a NaN explicitly.
2016-08-05 04:50:31 +08:00
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return (fn - fn) / (fn - fn);
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2018-05-30 04:52:24 +08:00
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else if (fn > M_LIT (65000.0))
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return M_SUF (__scalbn) (x, 65000);
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2011-10-12 23:27:51 +08:00
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else
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2018-05-30 04:52:24 +08:00
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return M_SUF (__scalbn) (x,-65000);
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2011-10-12 23:27:51 +08:00
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}
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2018-05-30 04:52:24 +08:00
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FLOAT
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M_DECL_FUNC (__ieee754_scalb) (FLOAT x, FLOAT fn)
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2011-10-12 23:27:51 +08:00
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{
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2015-06-03 22:36:34 +08:00
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if (__glibc_unlikely (isnan (x)))
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2011-10-12 23:27:51 +08:00
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return x * fn;
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2015-06-03 22:36:34 +08:00
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if (__glibc_unlikely (!isfinite (fn)))
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2011-10-12 23:27:51 +08:00
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{
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2018-05-30 04:52:24 +08:00
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if (isnan (fn) || fn > M_LIT (0.0))
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2011-10-12 23:27:51 +08:00
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return x * fn;
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2018-05-30 04:52:24 +08:00
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if (x == M_LIT (0.0))
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2011-10-12 23:27:51 +08:00
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return x;
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return x / -fn;
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}
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2018-05-30 04:52:24 +08:00
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if (__glibc_unlikely (M_FABS (fn) >= M_LIT (0x1p31)
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|| (FLOAT) (int) fn != fn))
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2011-10-12 23:27:51 +08:00
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return invalid_fn (x, fn);
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2018-05-30 04:52:24 +08:00
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return M_SCALBN (x, (int) fn);
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1996-03-06 05:41:30 +08:00
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}
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2018-05-30 04:52:24 +08:00
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declare_mgen_finite_alias (__ieee754_scalb, __scalb)
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