/* * Copyright (c) 2000 Apple Computer, Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * The contents of this file constitute Original Code as defined in and * are subject to the Apple Public Source License Version 1.1 (the * "License"). You may not use this file except in compliance with the * License. Please obtain a copy of the License at * http://www.apple.com/publicsource and read it before using this file. * * This 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 OR NON-INFRINGEMENT. Please see the * License for the specific language governing rights and limitations * under the License. * * @APPLE_LICENSE_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; }