122 lines
2.6 KiB
Plaintext
122 lines
2.6 KiB
Plaintext
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#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, 2011 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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#if defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7EM__) || defined(__ARM_ARCH_7S__)
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# define BOOST_SP_ARM_BARRIER "dmb"
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# define BOOST_SP_ARM_HAS_LDREX
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#elif defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__)
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# define BOOST_SP_ARM_BARRIER "mcr p15, 0, r0, c7, c10, 5"
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# define BOOST_SP_ARM_HAS_LDREX
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#else
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# define BOOST_SP_ARM_BARRIER ""
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#endif
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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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#ifdef BOOST_SP_ARM_HAS_LDREX
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__asm__ __volatile__(
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"ldrex %0, [%2]; \n"
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"cmp %0, %1; \n"
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"strexne %0, %1, [%2]; \n"
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BOOST_SP_ARM_BARRIER :
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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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#else
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__asm__ __volatile__(
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"swp %0, %1, [%2];\n"
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BOOST_SP_ARM_BARRIER :
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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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#endif
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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__( BOOST_SP_ARM_BARRIER ::: "memory" );
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*const_cast< int volatile* >( &v_ ) = 0;
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__asm__ __volatile__( BOOST_SP_ARM_BARRIER ::: "memory" );
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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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#undef BOOST_SP_ARM_BARRIER
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#undef BOOST_SP_ARM_HAS_LDREX
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#endif // #ifndef BOOST_SMART_PTR_DETAIL_SPINLOCK_GCC_ARM_HPP_INCLUDED
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