/* * Copyright (c) 2006 Apple Computer, Inc. All Rights Reserved. * * @APPLE_LICENSE_OSREFERENCE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. The rights granted to you under the * License may not be used to create, or enable the creation or * redistribution of, unlawful or unlicensed copies of an Apple operating * system, or to circumvent, violate, or enable the circumvention or * violation of, any terms of an Apple operating system software license * agreement. * * Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_LICENSE_OSREFERENCE_HEADER_END@ */ /* Copyright (c) 1991 NeXT Computer, Inc. All rights reserved. * * File: machdep/i386/libc/ffs.c * Author: Bruce Martin, NeXT Computer, Inc. * * This file contains machine dependent code for the ffs function * on NeXT i386-based products. Currently tuned for the i486. * * HISTORY * 27-Sep-92 Bruce Martin (Bruce_Martin@NeXT.COM) * Created: stolen from Mike's code. */ unsigned ffs(unsigned mask) { unsigned bitpos; if (mask == 0) return 0; bitpos = 1; while ((mask & 0xff) == 0) { bitpos += 8; mask >>= 8; } while ((mask & 1) == 0) { bitpos += 1; mask >>= 1; } return bitpos; }