bitops.h

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00001 /*
00002  * Copyright (C) 2006 Ondrej Palkovsky
00003  * All rights reserved.
00004  *
00005  * Redistribution and use in source and binary forms, with or without
00006  * modification, are permitted provided that the following conditions
00007  * are met:
00008  *
00009  * - Redistributions of source code must retain the above copyright
00010  *   notice, this list of conditions and the following disclaimer.
00011  * - Redistributions in binary form must reproduce the above copyright
00012  *   notice, this list of conditions and the following disclaimer in the
00013  *   documentation and/or other materials provided with the distribution.
00014  * - The name of the author may not be used to endorse or promote products
00015  *   derived from this software without specific prior written permission.
00016  *
00017  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
00018  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
00019  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
00020  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
00021  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
00022  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
00023  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
00024  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
00025  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
00026  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00027  */
00028 
00035 #ifndef _BITOPS_H_
00036 #define _BITOPS_H_
00037 
00038 #include <typedefs.h>
00039 
00040 
00045 static inline int fnzb32(__u32 arg)
00046 {
00047         int n = 0;
00048 
00049         if (arg >> 16) { arg >>= 16;n += 16;}
00050         if (arg >> 8) { arg >>= 8; n += 8;}
00051         if (arg >> 4) { arg >>= 4; n += 4;}
00052         if (arg >> 2) { arg >>= 2; n+=2;}
00053         if (arg >> 1) { arg >>= 1; n+=1;}
00054         return n;
00055 }
00056 
00057 static inline int fnzb64(__u64 arg)
00058 {
00059         int n = 0;
00060 
00061         if (arg >> 32) { arg >>= 32;n += 32;}
00062         return n + fnzb32((__u32) arg);
00063 }
00064 
00065 #define fnzb(x) fnzb32(x)
00066 
00067 #endif
00068 

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