glibc/sysdeps/ieee754/dbl-64/s_logb.c
Paul Eggert 581c785bf3 Update copyright dates with scripts/update-copyrights
I used these shell commands:

../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")

and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 7061 files FOO.

I then removed trailing white space from math/tgmath.h,
support/tst-support-open-dev-null-range.c, and
sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following
obscure pre-commit check failure diagnostics from Savannah.  I don't
know why I run into these diagnostics whereas others evidently do not.

remote: *** 912-#endif
remote: *** 913:
remote: *** 914-
remote: *** error: lines with trailing whitespace found
...
remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
2022-01-01 11:40:24 -08:00

49 lines
1.4 KiB
C

/* Compute radix independent exponent.
Copyright (C) 2011-2022 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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, see
<https://www.gnu.org/licenses/>. */
#include <math.h>
#include <math_private.h>
#include <libm-alias-double.h>
#include <fix-int-fp-convert-zero.h>
double
__logb (double x)
{
int64_t ix, ex;
EXTRACT_WORDS64 (ix, x);
ix &= UINT64_C(0x7fffffffffffffff);
if (ix == 0)
return -1.0 / fabs (x);
ex = ix >> 52;
if (ex == 0x7ff)
return x * x;
if (__glibc_unlikely (ex == 0))
{
int m = __builtin_clzll (ix);
ex -= m - 12;
}
if (FIX_INT_FP_CONVERT_ZERO && ex == 1023)
return 0.0;
return (double) (ex - 1023);
}
#ifndef __logb
libm_alias_double (__logb, logb)
#endif