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author | Ulrich Drepper <drepper@redhat.com> | 1998-12-26 09:30:54 +0000 |
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committer | Ulrich Drepper <drepper@redhat.com> | 1998-12-26 09:30:54 +0000 |
commit | 85f72e9c2a46601358e5e908053c13709b3003c3 (patch) | |
tree | 81d271ef44f1c5eeec78864acc54e471b13c9943 /sysdeps | |
parent | 65c64a0b4afc4814d11af5d185772eb48d72e6ce (diff) | |
download | glibc-85f72e9c2a46601358e5e908053c13709b3003c3.tar.gz glibc-85f72e9c2a46601358e5e908053c13709b3003c3.tar.xz glibc-85f72e9c2a46601358e5e908053c13709b3003c3.zip |
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.
Diffstat (limited to 'sysdeps')
-rw-r--r-- | sysdeps/generic/dl-hash.h | 74 | ||||
-rw-r--r-- | sysdeps/i386/i686/dl-hash.h | 80 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/arm/Makefile | 2 |
3 files changed, 155 insertions, 1 deletions
diff --git a/sysdeps/generic/dl-hash.h b/sysdeps/generic/dl-hash.h new file mode 100644 index 0000000000..fc17793324 --- /dev/null +++ b/sysdeps/generic/dl-hash.h @@ -0,0 +1,74 @@ +/* Compute hash alue for given string according to ELF standard. + Copyright (C) 1995, 1996, 1997, 1998 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 Library General Public License as + published by the Free Software Foundation; either version 2 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#ifndef _DL_HASH_H +#define _DL_HASH_H 1 + + +/* This is the hashing function specified by the ELF ABI. In the + first five operations no overflow is possible so we optimized it a + bit. */ +static inline unsigned int +_dl_elf_hash (const unsigned char *name) +{ + unsigned long int hash = 0; + if (*name != '\0') + { + hash = *name++; + if (*name != '\0') + { + hash = (hash << 4) + *name++; + if (*name != '\0') + { + hash = (hash << 4) + *name++; + if (*name != '\0') + { + hash = (hash << 4) + *name++; + if (*name != '\0') + { + hash = (hash << 4) + *name++; + while (*name != '\0') + { + unsigned long int hi; + hash = (hash << 4) + *name++; + hi = hash & 0xf0000000; + + /* The algorithm specified in the ELF ABI is as + follows: + + if (hi != 0) + hash ^= hi >> 24; + + hash &= ~hi; + + But the following is equivalent and a lot + faster, especially on modern processors. */ + + hash ^= hi; + hash ^= hi >> 24; + } + } + } + } + } + } + return hash; +} + +#endif /* dl-hash.h */ diff --git a/sysdeps/i386/i686/dl-hash.h b/sysdeps/i386/i686/dl-hash.h new file mode 100644 index 0000000000..809969cab0 --- /dev/null +++ b/sysdeps/i386/i686/dl-hash.h @@ -0,0 +1,80 @@ +/* Compute hash alue for given string according to ELF standard. + Copyright (C) 1998 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#ifndef _DL_HASH_H +#define _DL_HASH_H 1 + + +/* This is the hashing function specified by the ELF ABI. It is highly + optimized for the PII processors. Though it will run on i586 it + would be much slower than the generic C implementation. So don't + use it. */ +static inline unsigned int +_dl_elf_hash (const unsigned char *name) +{ + unsigned int result; + unsigned int temp0; + unsigned int temp1; + + __asm__ __volatile__ + ("movzbl (%1),%2\n\t" + "testl %2, %2\n\t" + "jz 1f\n\t" + "movl %2, %0\n\t" + "movzbl 1(%1), %2\n\t" + "jecxz 1f\n\t" + "shll $4, %0\n\t" + "addl %2, %0\n\t" + "movzbl 2(%1), %2\n\t" + "jecxz 1f\n\t" + "shll $4, %0\n\t" + "addl %2, %0\n\t" + "movzbl 3(%1), %2\n\t" + "jecxz 1f\n\t" + "shll $4, %0\n\t" + "addl %2, %0\n\t" + "movzbl 4(%1), %2\n\t" + "jecxz 1f\n\t" + "shll $4, %0\n\t" + "addl $5, %1\n\t" + "addl %2, %0\n\t" + "movzbl (%1), %2\n\t" + "jecxz 1f\n" + "2:\t" + "shll $4, %0\n\t" + "movl $0xf0000000, %3\n\t" + "incl %1\n\t" + "addl %2, %0\n\t" + "andl %0, %3\n\t" + "andl $0x0fffffff, %0\n\t" + "shrl $24, %3\n\t" + "movzbl (%1), %2\n\t" + "xorl %3, %0\n\t" + "testl %2, %2\n\t" + "jnz 2b\n" + "1:\t" + : "=&r" (result), "=r" (name), "=&c" (temp0), "=&r" (temp1) + : "0" (0), "1" (name)); + + return result; +} + +#endif /* dl-hash.h */ + diff --git a/sysdeps/unix/sysv/linux/arm/Makefile b/sysdeps/unix/sysv/linux/arm/Makefile index cebaa94134..d76698b405 100644 --- a/sysdeps/unix/sysv/linux/arm/Makefile +++ b/sysdeps/unix/sysv/linux/arm/Makefile @@ -1,5 +1,5 @@ ifeq ($(subdir),misc) -sysdep_routines += setfsgid setfsuid setresgid setresuid +sysdep_routines += setfsgid setfsuid setresgid setresuid ioperm endif ifeq ($(subdir),signal) |