Chris@16: #ifndef BOOST_SMART_PTR_DETAIL_SPINLOCK_GCC_ARM_HPP_INCLUDED
Chris@16: #define BOOST_SMART_PTR_DETAIL_SPINLOCK_GCC_ARM_HPP_INCLUDED
Chris@16: 
Chris@16: //
Chris@16: //  Copyright (c) 2008, 2011 Peter Dimov
Chris@16: //
Chris@16: //  Distributed under the Boost Software License, Version 1.0.
Chris@16: //  See accompanying file LICENSE_1_0.txt or copy at
Chris@16: //  http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: 
Chris@16: #include <boost/smart_ptr/detail/yield_k.hpp>
Chris@16: 
Chris@16: #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__)
Chris@16: 
Chris@16: # define BOOST_SP_ARM_BARRIER "dmb"
Chris@16: # define BOOST_SP_ARM_HAS_LDREX
Chris@16: 
Chris@16: #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__)
Chris@16: 
Chris@16: # define BOOST_SP_ARM_BARRIER "mcr p15, 0, r0, c7, c10, 5"
Chris@16: # define BOOST_SP_ARM_HAS_LDREX
Chris@16: 
Chris@16: #else
Chris@16: 
Chris@16: # define BOOST_SP_ARM_BARRIER ""
Chris@16: 
Chris@16: #endif
Chris@16: 
Chris@16: namespace boost
Chris@16: {
Chris@16: 
Chris@16: namespace detail
Chris@16: {
Chris@16: 
Chris@16: class spinlock
Chris@16: {
Chris@16: public:
Chris@16: 
Chris@16:     int v_;
Chris@16: 
Chris@16: public:
Chris@16: 
Chris@16:     bool try_lock()
Chris@16:     {
Chris@16:         int r;
Chris@16: 
Chris@16: #ifdef BOOST_SP_ARM_HAS_LDREX
Chris@16: 
Chris@16:         __asm__ __volatile__(
Chris@16:             "ldrex %0, [%2]; \n"
Chris@16:             "cmp %0, %1; \n"
Chris@16:             "strexne %0, %1, [%2]; \n"
Chris@16:             BOOST_SP_ARM_BARRIER :
Chris@16:             "=&r"( r ): // outputs
Chris@16:             "r"( 1 ), "r"( &v_ ): // inputs
Chris@16:             "memory", "cc" );
Chris@16: 
Chris@16: #else
Chris@16: 
Chris@16:         __asm__ __volatile__(
Chris@16:             "swp %0, %1, [%2];\n"
Chris@16:             BOOST_SP_ARM_BARRIER :
Chris@16:             "=&r"( r ): // outputs
Chris@16:             "r"( 1 ), "r"( &v_ ): // inputs
Chris@16:             "memory", "cc" );
Chris@16: 
Chris@16: #endif
Chris@16: 
Chris@16:         return r == 0;
Chris@16:     }
Chris@16: 
Chris@16:     void lock()
Chris@16:     {
Chris@16:         for( unsigned k = 0; !try_lock(); ++k )
Chris@16:         {
Chris@16:             boost::detail::yield( k );
Chris@16:         }
Chris@16:     }
Chris@16: 
Chris@16:     void unlock()
Chris@16:     {
Chris@16:         __asm__ __volatile__( BOOST_SP_ARM_BARRIER ::: "memory" );
Chris@16:         *const_cast< int volatile* >( &v_ ) = 0;
Chris@16:     }
Chris@16: 
Chris@16: public:
Chris@16: 
Chris@16:     class scoped_lock
Chris@16:     {
Chris@16:     private:
Chris@16: 
Chris@16:         spinlock & sp_;
Chris@16: 
Chris@16:         scoped_lock( scoped_lock const & );
Chris@16:         scoped_lock & operator=( scoped_lock const & );
Chris@16: 
Chris@16:     public:
Chris@16: 
Chris@16:         explicit scoped_lock( spinlock & sp ): sp_( sp )
Chris@16:         {
Chris@16:             sp.lock();
Chris@16:         }
Chris@16: 
Chris@16:         ~scoped_lock()
Chris@16:         {
Chris@16:             sp_.unlock();
Chris@16:         }
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: } // namespace detail
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #define BOOST_DETAIL_SPINLOCK_INIT {0}
Chris@16: 
Chris@16: #undef BOOST_SP_ARM_BARRIER
Chris@16: #undef BOOST_SP_ARM_HAS_LDREX
Chris@16: 
Chris@16: #endif // #ifndef BOOST_SMART_PTR_DETAIL_SPINLOCK_GCC_ARM_HPP_INCLUDED