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79 lines
2.3 KiB
C
79 lines
2.3 KiB
C
/* Compute hash alue for given string according to ELF standard.
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Copyright (C) 1998, 2003, 2005 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 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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#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 unsigned int
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_dl_elf_hash (const 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" ((const unsigned char *) name));
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return result;
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}
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#endif /* dl-hash.h */
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