1 files changed, 53 insertions, 0 deletions
diff --git a/lib/libc/i386/string/ffs.S b/lib/libc/i386/string/ffs.S
new file mode 100644
index 0000000..450f586
--- /dev/null
+++ b/lib/libc/i386/string/ffs.S
@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 1993 Winning Strategies, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *      This product includes software developed by Winning Strategies, Inc.
+ * 4. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <machine/asm.h>
+__FBSDID("$FreeBSD$");
+
+/*
+ * ffs(value)
+ *	finds the first bit set in value and returns the index of 
+ *	that bit.  Bits are numbered starting from 1, starting at the
+ *	rightmost bit.  A return value of 0 means that the argument
+ *	was zero.
+ *
+ * Written by:
+ *	J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc.
+ */
+
+ENTRY(ffs)
+	bsfl	4(%esp),%eax
+	jz	L1	 		/* ZF is set if all bits are 0 */
+	incl	%eax			/* bits numbered from 1, not 0 */
+	ret
+
+	.align 2
+L1:	xorl	%eax,%eax		/* clear result */
+	ret