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@ -1,41 +1,15 @@ |
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/*- |
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* Copyright (c) 1990 The Regents of the University of California. |
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* All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* 3. All advertising materials mentioning features or use of this software |
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* must display the following acknowledgement: |
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* This product includes software developed by the University of |
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* California, Berkeley and its contributors. |
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* 4. Neither the name of the University nor the names of its contributors |
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* may be used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. |
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/* $OpenBSD: ffs.c,v 1.4 2000/07/02 01:00:01 mickey Exp $ */ |
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/* |
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* Public domain. |
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* Written by Dale Rahn. |
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*/ |
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#if defined(LIBC_SCCS) && !defined(lint) |
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static char *rcsid = "$OpenBSD: ffs.c,v 1.3 1996/08/19 08:34:01 tholo Exp $"; |
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static char *rcsid = "$OpenBSD: ffs.c,v 1.4 2000/07/02 01:00:01 mickey Exp $"; |
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#endif /* LIBC_SCCS and not lint */ |
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#ifndef _KERNEL |
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#if !defined(_KERNEL) && !defined(_STANDALONE) |
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#include <string.h> |
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#else |
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#include <lib/libkern/libkern.h> |
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@ -49,10 +23,26 @@ ffs(mask) |
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register int mask; |
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{ |
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register int bit; |
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register unsigned int r = mask; |
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static const signed char t[16] = { |
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-28, 1, 2, 1, |
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3, 1, 2, 1, |
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4, 1, 2, 1, |
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3, 1, 2, 1 }; |
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bit = 0; |
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if (0 == (r & 0xffff)) { |
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bit += 16; |
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r >>= 16; |
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} |
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if (0 == (r & 0xff)) { |
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bit += 8; |
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r >>= 8; |
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} |
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if (0 == (r & 0xf)) { |
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bit += 4; |
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r >>= 4; |
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} |
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if (mask == 0) |
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return(0); |
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for (bit = 1; !(mask & 1); bit++) |
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mask >>= 1; |
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return(bit); |
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return (bit + t[ r & 0xf ]); |
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} |