1*69bb4bb4Scarlsonj /* 2*69bb4bb4Scarlsonj * CDDL HEADER START 3*69bb4bb4Scarlsonj * 4*69bb4bb4Scarlsonj * The contents of this file are subject to the terms of the 5*69bb4bb4Scarlsonj * Common Development and Distribution License (the "License"). 6*69bb4bb4Scarlsonj * You may not use this file except in compliance with the License. 7*69bb4bb4Scarlsonj * 8*69bb4bb4Scarlsonj * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9*69bb4bb4Scarlsonj * or http://www.opensolaris.org/os/licensing. 10*69bb4bb4Scarlsonj * See the License for the specific language governing permissions 11*69bb4bb4Scarlsonj * and limitations under the License. 12*69bb4bb4Scarlsonj * 13*69bb4bb4Scarlsonj * When distributing Covered Code, include this CDDL HEADER in each 14*69bb4bb4Scarlsonj * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15*69bb4bb4Scarlsonj * If applicable, add the following below this CDDL HEADER, with the 16*69bb4bb4Scarlsonj * fields enclosed by brackets "[]" replaced with your own identifying 17*69bb4bb4Scarlsonj * information: Portions Copyright [yyyy] [name of copyright owner] 18*69bb4bb4Scarlsonj * 19*69bb4bb4Scarlsonj * CDDL HEADER END 20*69bb4bb4Scarlsonj */ 21*69bb4bb4Scarlsonj 22*69bb4bb4Scarlsonj /* 23*69bb4bb4Scarlsonj * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 24*69bb4bb4Scarlsonj * Use is subject to license terms. 25*69bb4bb4Scarlsonj */ 26*69bb4bb4Scarlsonj 27*69bb4bb4Scarlsonj #pragma ident "%Z%%M% %I% %E% SMI" 28*69bb4bb4Scarlsonj 29*69bb4bb4Scarlsonj /* 30*69bb4bb4Scarlsonj * Common implementation of ffs for kernel, mdb, and libc. Note that mdb 31*69bb4bb4Scarlsonj * renames ffs into mdb_ffs to avoid user-space clashes with the signature of 32*69bb4bb4Scarlsonj * ffs(3C). 33*69bb4bb4Scarlsonj */ 34*69bb4bb4Scarlsonj 35*69bb4bb4Scarlsonj #if defined(_KERNEL) || defined(ffs) 36*69bb4bb4Scarlsonj #include <sys/int_types.h> 37*69bb4bb4Scarlsonj #define arg_t uintmax_t 38*69bb4bb4Scarlsonj #else 39*69bb4bb4Scarlsonj #pragma weak ffs = _ffs 40*69bb4bb4Scarlsonj #define arg_t int 41*69bb4bb4Scarlsonj #include "synonyms.h" 42*69bb4bb4Scarlsonj #endif 43*69bb4bb4Scarlsonj 44*69bb4bb4Scarlsonj int 45*69bb4bb4Scarlsonj ffs(arg_t bits) 46*69bb4bb4Scarlsonj { 47*69bb4bb4Scarlsonj int i; 48*69bb4bb4Scarlsonj 49*69bb4bb4Scarlsonj if (bits == 0) 50*69bb4bb4Scarlsonj return (0); 51*69bb4bb4Scarlsonj for (i = 1; ; i++, bits >>= 1) { 52*69bb4bb4Scarlsonj if (bits & 1) 53*69bb4bb4Scarlsonj break; 54*69bb4bb4Scarlsonj } 55*69bb4bb4Scarlsonj return (i); 56*69bb4bb4Scarlsonj } 57