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-rw-r--r--sysdeps/i386/i686/ffs.c45
1 files changed, 45 insertions, 0 deletions
diff --git a/sysdeps/i386/i686/ffs.c b/sysdeps/i386/i686/ffs.c
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+++ b/sysdeps/i386/i686/ffs.c
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+/* ffs -- find first set bit in a word, counted from least significant end.
+   For Intel 80x86, x>=6.
+   This file is part of the GNU C Library.
+   Copyright (C) 1991, 92, 93, 94, 97, 98 Free Software Foundation, Inc.
+   Contributed by Ulrich Drepper <drepper@cygnus.com>.
+
+   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.  */
+
+#include <string.h>
+
+#undef	ffs
+
+#ifdef	__GNUC__
+
+int
+__ffs (x)
+     int x;
+{
+  int cnt;
+  int tmp;
+
+  asm ("bsfl %2,%0\n"		/* Count low bits in X and store in %1.  */
+       "cmovel %1,%0\n"		/* If number was zero, use -1 as result.  */
+       : "=&r" (cnt), "=r" (tmp) : "rm" (x), "1" (-1));
+
+  return cnt + 1;
+}
+weak_alias (__ffs, ffs)
+
+#else
+#include <sysdeps/generic/ffs.c>
+#endif