diff options
| -rw-r--r-- | sys/lib/libkern/ffs.c | 67 |
1 files changed, 27 insertions, 40 deletions
diff --git a/sys/lib/libkern/ffs.c b/sys/lib/libkern/ffs.c index 4fac9223a1a..1a823fd9d3c 100644 --- a/sys/lib/libkern/ffs.c +++ b/sys/lib/libkern/ffs.c @@ -1,44 +1,15 @@ -/* $OpenBSD: ffs.c,v 1.3 1997/11/07 15:56:40 niklas Exp $ */ +/* $OpenBSD: ffs.c,v 1.4 2000/07/02 01:03:29 mickey Exp $ */ -/*- - * Copyright (c) 1990 The Regents of the University of California. - * All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * 3. All advertising materials mentioning features or use of this software - * must display the following acknowledgement: - * This product includes software developed by the University of - * California, Berkeley and its contributors. - * 4. Neither the name of the University nor the names of its contributors - * may be used to endorse or promote products derived from this software - * without specific prior written permission. - * - * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND - * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE - * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE - * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL - * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS - * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT - * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY - * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF - * SUCH DAMAGE. +/* + * Public domain. + * Written by Dale Rahn. */ #if defined(LIBC_SCCS) && !defined(lint) -/*static char *sccsid = "from: @(#)ffs.c 5.4 (Berkeley) 5/17/90";*/ -static char *rcsid = "$OpenBSD: ffs.c,v 1.3 1997/11/07 15:56:40 niklas Exp $"; +static char *rcsid = "$OpenBSD: ffs.c,v 1.4 2000/07/02 01:03:29 mickey Exp $"; #endif /* LIBC_SCCS and not lint */ -#ifndef _KERNEL +#if !defined(_KERNEL) && !defined(_STANDALONE) #include <string.h> #else #include <lib/libkern/libkern.h> @@ -52,10 +23,26 @@ ffs(mask) register int mask; { register int bit; + register unsigned int r = mask; + static const signed char t[16] = { + -28, 1, 2, 1, + 3, 1, 2, 1, + 4, 1, 2, 1, + 3, 1, 2, 1 }; + + bit = 0; + if (0 == (r & 0xffff)) { + bit += 16; + r >>= 16; + } + if (0 == (r & 0xff)) { + bit += 8; + r >>= 8; + } + if (0 == (r & 0xf)) { + bit += 4; + r >>= 4; + } - if (mask == 0) - return(0); - for (bit = 1; !(mask & 1); bit++) - mask >>= 1; - return(bit); + return (bit + t[ r & 0xf ]); } |