μHAL (v2.7.9)
Part of the IPbus software repository
uhal
src
common
utilities
bits.cpp
Go to the documentation of this file.
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/*
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---------------------------------------------------------------------------
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This file is part of uHAL.
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uHAL is a hardware access library and programming framework
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originally developed for upgrades of the Level-1 trigger of the CMS
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experiment at CERN.
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uHAL is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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uHAL is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with uHAL. If not, see <http://www.gnu.org/licenses/>.
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Andrew Rose, Imperial College, London
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email: awr01 <AT> imperial.ac.uk
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Marc Magrans de Abril, CERN
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email: marc.magrans.de.abril <AT> cern.ch
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Tom Williams, Rutherford Appleton Laboratory, Oxfordshire
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email: tom.williams <AT> cern.ch
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---------------------------------------------------------------------------
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*/
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#include "
uhal/utilities/bits.hpp
"
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namespace
uhal
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{
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namespace
utilities
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{
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unsigned
int
TrailingRightBits
( uint32_t aValue )
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{
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// unsigned int lReturn = sizeof ( aValue ) * 8; // lReturn will be the number of zero bits on the right
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unsigned
int
lReturn =
sizeof
( aValue ) << 3;
// lReturn will be the number of zero bits on the right
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aValue &= -signed ( aValue );
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if
( aValue )
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{
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lReturn--;
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}
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if
( aValue & 0x0000FFFF )
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{
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lReturn -= 16;
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}
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if
( aValue & 0x00FF00FF )
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{
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lReturn -= 8;
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}
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if
( aValue & 0x0F0F0F0F )
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{
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lReturn -= 4;
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}
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if
( aValue & 0x33333333 )
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{
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lReturn -= 2;
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}
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if
( aValue & 0x55555555 )
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{
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lReturn -= 1;
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}
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return
lReturn;
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}
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}
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}
uhal
Definition:
HttpResponseGrammar.hpp:49
bits.hpp
uhal::utilities::TrailingRightBits
unsigned int TrailingRightBits(uint32_t aValue)
Helper function to calculate the number of zero-bits at the righthand end of a 32-bit number.
Definition:
bits.cpp:44
Generated on Tue Sep 22 2020 19:18:39 for μHAL (v2.7.9) by
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