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.

1 files changed, 80 insertions, 0 deletions

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 */
+