86 lines
1.5 KiB
C++
86 lines
1.5 KiB
C++
#ifndef BOOST_SMART_PTR_DETAIL_SPINLOCK_GCC_ARM_HPP_INCLUDED
|
|
#define BOOST_SMART_PTR_DETAIL_SPINLOCK_GCC_ARM_HPP_INCLUDED
|
|
|
|
//
|
|
// Copyright (c) 2008 Peter Dimov
|
|
//
|
|
// Distributed under the Boost Software License, Version 1.0.
|
|
// See accompanying file LICENSE_1_0.txt or copy at
|
|
// http://www.boost.org/LICENSE_1_0.txt)
|
|
//
|
|
|
|
#include <boost/smart_ptr/detail/yield_k.hpp>
|
|
|
|
namespace boost
|
|
{
|
|
|
|
namespace detail
|
|
{
|
|
|
|
class spinlock
|
|
{
|
|
public:
|
|
|
|
int v_;
|
|
|
|
public:
|
|
|
|
bool try_lock()
|
|
{
|
|
int r;
|
|
|
|
__asm__ __volatile__(
|
|
"swp %0, %1, [%2]":
|
|
"=&r"( r ): // outputs
|
|
"r"( 1 ), "r"( &v_ ): // inputs
|
|
"memory", "cc" );
|
|
|
|
return r == 0;
|
|
}
|
|
|
|
void lock()
|
|
{
|
|
for( unsigned k = 0; !try_lock(); ++k )
|
|
{
|
|
boost::detail::yield( k );
|
|
}
|
|
}
|
|
|
|
void unlock()
|
|
{
|
|
__asm__ __volatile__( "" ::: "memory" );
|
|
*const_cast< int volatile* >( &v_ ) = 0;
|
|
}
|
|
|
|
public:
|
|
|
|
class scoped_lock
|
|
{
|
|
private:
|
|
|
|
spinlock & sp_;
|
|
|
|
scoped_lock( scoped_lock const & );
|
|
scoped_lock & operator=( scoped_lock const & );
|
|
|
|
public:
|
|
|
|
explicit scoped_lock( spinlock & sp ): sp_( sp )
|
|
{
|
|
sp.lock();
|
|
}
|
|
|
|
~scoped_lock()
|
|
{
|
|
sp_.unlock();
|
|
}
|
|
};
|
|
};
|
|
|
|
} // namespace detail
|
|
} // namespace boost
|
|
|
|
#define BOOST_DETAIL_SPINLOCK_INIT {0}
|
|
|
|
#endif // #ifndef BOOST_SMART_PTR_DETAIL_SPINLOCK_GCC_ARM_HPP_INCLUDED
|