17c478bd9Sstevel@tonic-gate /* 27c478bd9Sstevel@tonic-gate * CDDL HEADER START 37c478bd9Sstevel@tonic-gate * 47c478bd9Sstevel@tonic-gate * 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. 77c478bd9Sstevel@tonic-gate * 87c478bd9Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 97c478bd9Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing. 107c478bd9Sstevel@tonic-gate * See the License for the specific language governing permissions 117c478bd9Sstevel@tonic-gate * and limitations under the License. 127c478bd9Sstevel@tonic-gate * 137c478bd9Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each 147c478bd9Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 157c478bd9Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the 167c478bd9Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying 177c478bd9Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner] 187c478bd9Sstevel@tonic-gate * 197c478bd9Sstevel@tonic-gate * CDDL HEADER END 207c478bd9Sstevel@tonic-gate */ 21*69bb4bb4Scarlsonj 227c478bd9Sstevel@tonic-gate /* 23*69bb4bb4Scarlsonj * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 247c478bd9Sstevel@tonic-gate * Use is subject to license terms. 257c478bd9Sstevel@tonic-gate */ 267c478bd9Sstevel@tonic-gate 277c478bd9Sstevel@tonic-gate #pragma ident "%Z%%M% %I% %E% SMI" 287c478bd9Sstevel@tonic-gate 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 */ 347c478bd9Sstevel@tonic-gate 35*69bb4bb4Scarlsonj #if defined(_KERNEL) || defined(ffs) 36*69bb4bb4Scarlsonj #include <sys/int_types.h> 37*69bb4bb4Scarlsonj #define arg_t uintmax_t 38*69bb4bb4Scarlsonj #else 397c478bd9Sstevel@tonic-gate #pragma weak ffs = _ffs 40*69bb4bb4Scarlsonj #define arg_t int 417c478bd9Sstevel@tonic-gate #include "synonyms.h" 42*69bb4bb4Scarlsonj #endif 437c478bd9Sstevel@tonic-gate 447c478bd9Sstevel@tonic-gate int 45*69bb4bb4Scarlsonj ffs(arg_t bits) 467c478bd9Sstevel@tonic-gate { 47*69bb4bb4Scarlsonj int i; 487c478bd9Sstevel@tonic-gate 49*69bb4bb4Scarlsonj if (bits == 0) 507c478bd9Sstevel@tonic-gate return (0); 51*69bb4bb4Scarlsonj for (i = 1; ; i++, bits >>= 1) { 52*69bb4bb4Scarlsonj if (bits & 1) 53*69bb4bb4Scarlsonj break; 547c478bd9Sstevel@tonic-gate } 55*69bb4bb4Scarlsonj return (i); 567c478bd9Sstevel@tonic-gate } 57