1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 #pragma ident "%Z%%M% %I% %E% SMI" 28 29 /* 30 * Common implementation of ffs for kernel, mdb, and libc. Note that mdb 31 * renames ffs into mdb_ffs to avoid user-space clashes with the signature of 32 * ffs(3C). 33 */ 34 35 #if defined(_KERNEL) || defined(ffs) 36 #include <sys/int_types.h> 37 #define arg_t uintmax_t 38 #else 39 #pragma weak ffs = _ffs 40 #define arg_t int 41 #include "synonyms.h" 42 #endif 43 44 int 45 ffs(arg_t bits) 46 { 47 int i; 48 49 if (bits == 0) 50 return (0); 51 for (i = 1; ; i++, bits >>= 1) { 52 if (bits & 1) 53 break; 54 } 55 return (i); 56 } 57