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