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Diffstat (limited to 'sysdeps/i386/i686/ffs.c')
-rw-r--r--sysdeps/i386/i686/ffs.c45
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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