xref: /original-bsd/lib/libc/string/ffs.c (revision 65ba69af)
1 /*
2  * Copyright (c) 1987 Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms are permitted
6  * provided that the above copyright notice and this paragraph are
7  * duplicated in all such forms and that any documentation,
8  * advertising materials, and other materials related to such
9  * distribution and use acknowledge that the software was developed
10  * by the University of California, Berkeley.  The name of the
11  * University may not be used to endorse or promote products derived
12  * from this software without specific prior written permission.
13  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16  */
17 
18 #if defined(LIBC_SCCS) && !defined(lint)
19 static char sccsid[] = "@(#)ffs.c	5.2 (Berkeley) 06/27/88";
20 #endif /* LIBC_SCCS and not lint */
21 
22 /*
23  * ffs -- vax ffs instruction
24  */
25 ffs(mask)
26 	register long mask;
27 {
28 	register int cnt;
29 
30 	if (mask == 0)
31 		return(0);
32 	for (cnt = 1; !(mask & 1); cnt++)
33 		mask >>= 1;
34 	return(cnt);
35 }
36