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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 @@
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2019-07-08 Adhemerval Zanella <adhemerval.zanella@linaro.org>
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* sysdeps/ieee754/dbl-64/wordsize-64/s_logb.c: Move to ...
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* sysdeps/ieee754/dbl-64/s_logb.c: ... here. Add work around for
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powerpc32 integer 0 converting to -0.
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* benchtests/Makefile (bench-math): Add logb.
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* benchtests/logb-inputs: New file.
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* benchtests/logbf-inputs: New file.
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@ -1,22 +1,24 @@
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/* @(#)s_logb.c 5.1 93/09/24 */
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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/* Compute radix independent exponent.
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Copyright (C) 2011-2019 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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/*
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* double logb(x)
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* IEEE 754 logb. Included to pass IEEE test suite. Not recommend.
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* Use ilogb instead.
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*/
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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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#include <fix-int-fp-convert-zero.h>
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@ -24,28 +26,23 @@
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double
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__logb (double x)
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{
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int32_t lx, ix, rix;
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int64_t ix, ex;
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EXTRACT_WORDS (ix, lx, x);
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ix &= 0x7fffffff; /* high |x| */
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if ((ix | lx) == 0)
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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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if (ix >= 0x7ff00000)
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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 ((rix = ix >> 20) == 0))
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if (__glibc_unlikely (ex == 0))
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{
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/* POSIX specifies that denormal number is treated as
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though it were normalized. */
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int ma;
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if (ix == 0)
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ma = __builtin_clz (lx) + 32;
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else
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ma = __builtin_clz (ix);
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rix -= ma - 12;
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int m = __builtin_clzll (ix);
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ex -= m - 12;
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}
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if (FIX_INT_FP_CONVERT_ZERO && rix == 1023)
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if (FIX_INT_FP_CONVERT_ZERO && ex == 1023)
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return 0.0;
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return (double) (rix - 1023);
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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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@ -1,47 +0,0 @@
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/* Compute radix independent exponent.
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Copyright (C) 2011-2019 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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