mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-10 15:20:10 +00:00
math: Use wordsize-64 version for s_logb
- The resulting binary difference on 32 bits architecture is
minimum. On i686-linux-gnu (with architecture optimization
routine removed) there is no different using logb benchtests
- It helps wordsize-64 architectures that use ldbl-opt.
- It add some code simplification with reduction of duplicated
implementations.
Checked on powerpc-linux-gnu (built without --with-cpu, with
--with-cpu=power4 and with --with-cpu=power5+ and --disable-multi-arch),
powerpc64-linux-gnu (built without --with-cp and with --with-cpu=power5+
and --disable-multi-arch).
* sysdeps/ieee754/dbl-64/wordsize-64/s_logb.c: Move to ...
* sysdeps/ieee754/dbl-64/s_logb.c: ... here. Add work around for
powerpc32 integer 0 converting to -0.
Reviewed-by: Gabriel F. T. Gomes <gabrielftg@linux.ibm.com>
This commit is contained in:
Adhemerval Zanella
parent
0cccd37f70
commit
105f2ed368
@ -1,5 +1,9 @@
|
||||
2019-07-08 Adhemerval Zanella <adhemerval.zanella@linaro.org>
|
||||
|
||||
* sysdeps/ieee754/dbl-64/wordsize-64/s_logb.c: Move to ...
|
||||
* sysdeps/ieee754/dbl-64/s_logb.c: ... here. Add work around for
|
||||
powerpc32 integer 0 converting to -0.
|
||||
|
||||
* benchtests/Makefile (bench-math): Add logb.
|
||||
* benchtests/logb-inputs: New file.
|
||||
* benchtests/logbf-inputs: New file.
|
||||
|
||||
@ -1,22 +1,24 @@
|
||||
/* @(#)s_logb.c 5.1 93/09/24 */
|
||||
/*
|
||||
* ====================================================
|
||||
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
|
||||
*
|
||||
* Developed at SunPro, a Sun Microsystems, Inc. business.
|
||||
* Permission to use, copy, modify, and distribute this
|
||||
* software is freely granted, provided that this notice
|
||||
* is preserved.
|
||||
* ====================================================
|
||||
*/
|
||||
/* Compute radix independent exponent.
|
||||
Copyright (C) 2011-2019 Free Software Foundation, Inc.
|
||||
This file is part of the GNU C Library.
|
||||
Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.
|
||||
|
||||
/*
|
||||
* double logb(x)
|
||||
* IEEE 754 logb. Included to pass IEEE test suite. Not recommend.
|
||||
* Use ilogb instead.
|
||||
*/
|
||||
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
|
||||
<http://www.gnu.org/licenses/>. */
|
||||
|
||||
#include <math.h>
|
||||
|
||||
#include <math_private.h>
|
||||
#include <libm-alias-double.h>
|
||||
#include <fix-int-fp-convert-zero.h>
|
||||
@ -24,28 +26,23 @@
|
||||
double
|
||||
__logb (double x)
|
||||
{
|
||||
int32_t lx, ix, rix;
|
||||
int64_t ix, ex;
|
||||
|
||||
EXTRACT_WORDS (ix, lx, x);
|
||||
ix &= 0x7fffffff; /* high |x| */
|
||||
if ((ix | lx) == 0)
|
||||
EXTRACT_WORDS64 (ix, x);
|
||||
ix &= UINT64_C(0x7fffffffffffffff);
|
||||
if (ix == 0)
|
||||
return -1.0 / fabs (x);
|
||||
if (ix >= 0x7ff00000)
|
||||
ex = ix >> 52;
|
||||
if (ex == 0x7ff)
|
||||
return x * x;
|
||||
if (__glibc_unlikely ((rix = ix >> 20) == 0))
|
||||
if (__glibc_unlikely (ex == 0))
|
||||
{
|
||||
/* POSIX specifies that denormal number is treated as
|
||||
though it were normalized. */
|
||||
int ma;
|
||||
if (ix == 0)
|
||||
ma = __builtin_clz (lx) + 32;
|
||||
else
|
||||
ma = __builtin_clz (ix);
|
||||
rix -= ma - 12;
|
||||
int m = __builtin_clzll (ix);
|
||||
ex -= m - 12;
|
||||
}
|
||||
if (FIX_INT_FP_CONVERT_ZERO && rix == 1023)
|
||||
if (FIX_INT_FP_CONVERT_ZERO && ex == 1023)
|
||||
return 0.0;
|
||||
return (double) (rix - 1023);
|
||||
return (double) (ex - 1023);
|
||||
}
|
||||
#ifndef __logb
|
||||
libm_alias_double (__logb, logb)
|
||||
|
||||
@ -1,47 +0,0 @@
|
||||
/* Compute radix independent exponent.
|
||||
Copyright (C) 2011-2019 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, see
|
||||
<http://www.gnu.org/licenses/>. */
|
||||
|
||||
#include <math.h>
|
||||
|
||||
#include <math_private.h>
|
||||
#include <libm-alias-double.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;
|
||||
}
|
||||
return (double) (ex - 1023);
|
||||
}
|
||||
#ifndef __logb
|
||||
libm_alias_double (__logb, logb)
|
||||
#endif
|
||||
Loading…
Reference in New Issue
Block a user