00001 /* Copyright (c) 2007, Dmitry Xmelkov 00002 All rights reserved. 00003 00004 Redistribution and use in source and binary forms, with or without 00005 modification, are permitted provided that the following conditions are met: 00006 00007 * Redistributions of source code must retain the above copyright 00008 notice, this list of conditions and the following disclaimer. 00009 * Redistributions in binary form must reproduce the above copyright 00010 notice, this list of conditions and the following disclaimer in 00011 the documentation and/or other materials provided with the 00012 distribution. 00013 * Neither the name of the copyright holders nor the names of 00014 contributors may be used to endorse or promote products derived 00015 from this software without specific prior written permission. 00016 00017 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 00018 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 00019 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 00020 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 00021 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 00022 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 00023 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 00024 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 00025 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 00026 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 00027 POSSIBILITY OF SUCH DAMAGE. */ 00028 00029 /* $Id: ntz.h 1217 2007-02-18 13:18:05Z dmix $ */ 00030 00031 #ifndef _NTZ_H 00032 #define _NTZ_H 00033 00034 /* Number of Tail Zeros: ntz(x)= (ffs(x) ? ffs(x)-1 : 16) 00035 It works with all: cpp, gcc and gas expressions. */ 00036 #define ntz(x) \ 00037 ( (1 & (((x) & 1) == 0)) \ 00038 + (1 & (((x) & 3) == 0)) \ 00039 + (1 & (((x) & 7) == 0)) \ 00040 + (1 & (((x) & 017) == 0)) \ 00041 + (1 & (((x) & 037) == 0)) \ 00042 + (1 & (((x) & 077) == 0)) \ 00043 + (1 & (((x) & 0177) == 0)) \ 00044 + (1 & (((x) & 0377) == 0)) \ 00045 + (1 & (((x) & 0777) == 0)) \ 00046 + (1 & (((x) & 01777) == 0)) \ 00047 + (1 & (((x) & 03777) == 0)) \ 00048 + (1 & (((x) & 07777) == 0)) \ 00049 + (1 & (((x) & 017777) == 0)) \ 00050 + (1 & (((x) & 037777) == 0)) \ 00051 + (1 & (((x) & 077777) == 0)) \ 00052 + (1 & (((x) & 0177777) == 0)) ) 00053 00054 #endif /* !_NTZ_H */