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78 lines
2.2 KiB
C++
78 lines
2.2 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2012, 2013.
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This file is part of Sortix.
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Sortix is free software: you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation, either version 3 of the License, or (at your option) any later
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version.
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Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along with
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Sortix. If not, see <http://www.gnu.org/licenses/>.
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interlock.cpp
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Functions that perform non-atomic operations in an atomic manner.
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*******************************************************************************/
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#include <sortix/kernel/platform.h>
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#include <sortix/kernel/interlock.h>
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namespace Sortix {
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// TODO: This is likely not the most optimal way to perform these operations.
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ilret_t InterlockedModify(unsigned long* ptr,
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ilockfunc f,
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unsigned long user)
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{
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unsigned long old_value, new_value;
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do
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{
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old_value = *((volatile unsigned long*) ptr); /* TODO: Need volatile? */
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new_value = f(old_value, user);
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} while ( !__sync_bool_compare_and_swap(ptr, old_value, new_value) );
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ilret_t ret;
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ret.o = old_value;
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ret.n = new_value;
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return ret;
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}
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static unsigned long AddFunction(unsigned long val, unsigned long arg)
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{
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return val + arg;
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}
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static unsigned long SubFunction(unsigned long val, unsigned long arg)
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{
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return val - arg;
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}
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ilret_t InterlockedIncrement(unsigned long* ptr)
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{
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return InterlockedModify(ptr, AddFunction, 1);
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}
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ilret_t InterlockedDecrement(unsigned long* ptr)
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{
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return InterlockedModify(ptr, SubFunction, 1);
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}
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ilret_t InterlockedAdd(unsigned long* ptr, unsigned long arg)
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{
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return InterlockedModify(ptr, AddFunction, arg);
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}
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ilret_t InterlockedSub(unsigned long* ptr, unsigned long arg)
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{
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return InterlockedModify(ptr, SubFunction, arg);
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}
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} // namespace Sortix
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