Update.
1998-12-25 Ulrich Drepper <drepper@cygnus.com> * elf/dl-hash.h: Move to... * sysdeps/generic/dl-hash.h: ...here. Correct parameter type (must be unsigned char). Remove conditional from inner loop and rearrange binary operations (12-22% performance increase). * sysdeps/i386/i686/dl-hash.h: New file. Yet 10% faster than optimized generic version.
This commit is contained in:
Ulrich Drepper
parent
65c64a0b4a
commit
85f72e9c2a
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@ -1,3 +1,12 @@
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1998-12-25 Ulrich Drepper <drepper@cygnus.com>
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* elf/dl-hash.h: Move to...
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* sysdeps/generic/dl-hash.h: ...here. Correct parameter type (must
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be unsigned char). Remove conditional from inner loop and rearrange
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binary operations (12-22% performance increase).
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* sysdeps/i386/i686/dl-hash.h: New file. Yet 10% faster than
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optimized generic version.
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1998-12-23 Ulrich Drepper <drepper@cygnus.com>
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* elf/dl-lookup.c (do_lookup): If looking up an unversioned symbol
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@ -24,7 +24,8 @@ all: # Make this the default target; it will be defined in Rules.
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# List with all available character set descriptions.
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charmaps := $(filter-out $(addprefix charmaps/, CVS RCS %~), \
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$(wildcard charmaps/*))
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$(wildcard charmaps/[A-I]*) \
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$(wildcard charmaps/[J-Z]*))
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# List with all available character set descriptions.
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locales := $(filter-out $(addprefix locales/, CVS RCS %~), \
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@ -1,5 +1,5 @@
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/* Compute hash alue for given string according to ELF standard.
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Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.
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Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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@ -22,15 +22,15 @@
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/* This is the hashing function specified by the ELF ABI. In the
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first five operations now overflow is possible so we optimized it a
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first five operations no overflow is possible so we optimized it a
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bit. */
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static inline unsigned
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_dl_elf_hash (const char *name)
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static inline unsigned int
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_dl_elf_hash (const unsigned char *name)
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{
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unsigned long int hash = 0;
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if (*name != '\0')
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{
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hash = (hash << 4) + *name++;
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hash = *name++;
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if (*name != '\0')
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{
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hash = (hash << 4) + *name++;
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@ -48,15 +48,20 @@ _dl_elf_hash (const char *name)
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unsigned long int hi;
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hash = (hash << 4) + *name++;
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hi = hash & 0xf0000000;
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if (hi != 0)
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{
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hash ^= hi >> 24;
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/* The ELF ABI says `hash &= ~hi', but
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this is equivalent in this case and
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on some machines one insn instead of
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two. */
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hash ^= hi;
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}
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/* The algorithm specified in the ELF ABI is as
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follows:
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if (hi != 0)
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hash ^= hi >> 24;
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hash &= ~hi;
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But the following is equivalent and a lot
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faster, especially on modern processors. */
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hash ^= hi;
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hash ^= hi >> 24;
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}
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}
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}
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@ -0,0 +1,80 @@
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/* Compute hash alue for given string according to ELF standard.
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Copyright (C) 1998 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@cygnus.com>, 1998.
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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 Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#ifndef _DL_HASH_H
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#define _DL_HASH_H 1
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/* This is the hashing function specified by the ELF ABI. It is highly
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optimized for the PII processors. Though it will run on i586 it
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would be much slower than the generic C implementation. So don't
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use it. */
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static inline unsigned int
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_dl_elf_hash (const unsigned char *name)
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{
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unsigned int result;
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unsigned int temp0;
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unsigned int temp1;
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__asm__ __volatile__
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("movzbl (%1),%2\n\t"
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"testl %2, %2\n\t"
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"jz 1f\n\t"
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"movl %2, %0\n\t"
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"movzbl 1(%1), %2\n\t"
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"jecxz 1f\n\t"
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"shll $4, %0\n\t"
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"addl %2, %0\n\t"
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"movzbl 2(%1), %2\n\t"
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"jecxz 1f\n\t"
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"shll $4, %0\n\t"
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"addl %2, %0\n\t"
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"movzbl 3(%1), %2\n\t"
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"jecxz 1f\n\t"
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"shll $4, %0\n\t"
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"addl %2, %0\n\t"
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"movzbl 4(%1), %2\n\t"
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"jecxz 1f\n\t"
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"shll $4, %0\n\t"
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"addl $5, %1\n\t"
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"addl %2, %0\n\t"
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"movzbl (%1), %2\n\t"
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"jecxz 1f\n"
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"2:\t"
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"shll $4, %0\n\t"
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"movl $0xf0000000, %3\n\t"
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"incl %1\n\t"
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"addl %2, %0\n\t"
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"andl %0, %3\n\t"
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"andl $0x0fffffff, %0\n\t"
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"shrl $24, %3\n\t"
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"movzbl (%1), %2\n\t"
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"xorl %3, %0\n\t"
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"testl %2, %2\n\t"
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"jnz 2b\n"
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"1:\t"
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: "=&r" (result), "=r" (name), "=&c" (temp0), "=&r" (temp1)
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: "0" (0), "1" (name));
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return result;
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}
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#endif /* dl-hash.h */
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@ -1,5 +1,5 @@
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ifeq ($(subdir),misc)
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sysdep_routines += setfsgid setfsuid setresgid setresuid
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sysdep_routines += setfsgid setfsuid setresgid setresuid ioperm
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endif
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ifeq ($(subdir),signal)
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