mirror of https://github.com/ArduPilot/ardupilot
55 lines
2.3 KiB
C
55 lines
2.3 KiB
C
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/* Copyright (c) 2007, Dmitry Xmelkov
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All rights reserved.
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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 are met:
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* 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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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the
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distribution.
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* Neither the name of the copyright holders nor the names of
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contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND 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 COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE. */
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/* $Id: ntz.h 1217 2007-02-18 13:18:05Z dmix $ */
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#ifndef _NTZ_H
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#define _NTZ_H
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/* Number of Tail Zeros: ntz(x)= (ffs(x) ? ffs(x)-1 : 16)
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It works with all: cpp, gcc and gas expressions. */
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#define ntz(x) \
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( (1 & (((x) & 1) == 0)) \
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+ (1 & (((x) & 3) == 0)) \
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+ (1 & (((x) & 7) == 0)) \
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+ (1 & (((x) & 017) == 0)) \
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+ (1 & (((x) & 037) == 0)) \
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+ (1 & (((x) & 077) == 0)) \
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+ (1 & (((x) & 0177) == 0)) \
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+ (1 & (((x) & 0377) == 0)) \
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+ (1 & (((x) & 0777) == 0)) \
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+ (1 & (((x) & 01777) == 0)) \
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+ (1 & (((x) & 03777) == 0)) \
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+ (1 & (((x) & 07777) == 0)) \
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+ (1 & (((x) & 017777) == 0)) \
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+ (1 & (((x) & 037777) == 0)) \
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+ (1 & (((x) & 077777) == 0)) \
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+ (1 & (((x) & 0177777) == 0)) )
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#endif /* !_NTZ_H */
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