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 2008 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* 28 * Common implementation of ffs for kernel, mdb, and libc. Note that mdb 29 * renames ffs into mdb_ffs to avoid user-space clashes with the signature of 30 * ffs(3C). 31 */ 32 33 #if defined(_KERNEL) || defined(ffs) 34 #include <sys/int_types.h> 35 #define arg_t uintmax_t 36 #else 37 #define arg_t int 38 #include "lint.h" 39 #endif 40 41 int 42 ffs(arg_t bits) 43 { 44 int i; 45 46 if (bits == 0) 47 return (0); 48 for (i = 1; ; i++, bits >>= 1) { 49 if (bits & 1) 50 break; 51 } 52 return (i); 53 } 54