From 85f72e9c2a46601358e5e908053c13709b3003c3 Mon Sep 17 00:00:00 2001 From: Ulrich Drepper Date: Sat, 26 Dec 1998 09:30:54 +0000 Subject: Update. 1998-12-25 Ulrich Drepper * 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. --- sysdeps/i386/i686/dl-hash.h | 80 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 80 insertions(+) create mode 100644 sysdeps/i386/i686/dl-hash.h (limited to 'sysdeps/i386/i686/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 , 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 */ + -- cgit 1.4.1