libcruft-util/thread/ticketlock.cpp

46 lines
1.1 KiB
C++

/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Copyright 2018 Danny Robson <danny@nerdcruft.net>
*/
#include "ticketlock.hpp"
using util::thread::ticketlock;
///////////////////////////////////////////////////////////////////////////////
ticketlock::ticketlock ():
current (0),
next (0)
{ }
///////////////////////////////////////////////////////////////////////////////
void
ticketlock::lock (void)
{
auto self = next++;
while (current != self)
__asm__ volatile ("pause");
}
//-----------------------------------------------------------------------------
void
ticketlock::unlock (void)
{
++current;
}