text: #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_X86_HPP_INCLUDED
  #define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_X86_HPP_INCLUDED
  
  // MS compatible compilers support #pragma once
  
  #if defined(_MSC_VER) && (_MSC_VER >= 1020)
  # pragma once
  #endif
  
  //
  //  detail/sp_counted_base_gcc_x86.hpp - g++ on 486+ or AMD64
  //
  //  Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
  //  Copyright 2004-2005 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)
  //
  //
  //  Lock-free algorithm by Alexander Terekhov
  //
  //  Thanks to Ben Hitchings for the #weak + (#shared != 0)
  //  formulation
  //
  
  #include <boost/smart_ptr/detail/sp_typeinfo_.hpp>
  #include <boost/smart_ptr/detail/sp_obsolete.hpp>
  #include <boost/config.hpp>
  
  #if defined(BOOST_SP_REPORT_IMPLEMENTATION)
  
  #include <boost/config/pragma_message.hpp>
  BOOST_PRAGMA_MESSAGE("Using g++/x86 sp_counted_base")
  
  #endif
  
  BOOST_SP_OBSOLETE()
  
  namespace lslboost
  {
  
  namespace detail
  {
  
  inline int atomic_exchange_and_add( int * pw, int dv )
  {
      // int r = *pw;
      // *pw += dv;
      // return r;
  
      int r;
  
      __asm__ __volatile__
      (
          "lock\n\t"
          "xadd %1, %0":
          "=m"( *pw ), "=r"( r ): // outputs (%0, %1)
          "m"( *pw ), "1"( dv ): // inputs (%2, %3 == %1)
          "memory", "cc" // clobbers
      );
  
      return r;
  }
  
  inline void atomic_increment( int * pw )
  {
      //atomic_exchange_and_add( pw, 1 );
  
      __asm__
      (
          "lock\n\t"
          "incl %0":
          "=m"( *pw ): // output (%0)
          "m"( *pw ): // input (%1)
          "cc" // clobbers
      );
  }
  
  inline int atomic_conditional_increment( int * pw )
  {
      // int rv = *pw;
      // if( rv != 0 ) ++*pw;
      // return rv;
  
      int rv, tmp;
  
      __asm__
      (
          "movl %0, %%eax\n\t"
          "0:\n\t"
          "test %%eax, %%eax\n\t"
          "je 1f\n\t"
          "movl %%eax, %2\n\t"
          "incl %2\n\t"
          "lock\n\t"
          "cmpxchgl %2, %0\n\t"
          "jne 0b\n\t"
          "1:":
          "=m"( *pw ), "=&a"( rv ), "=&r"( tmp ): // outputs (%0, %1, %2)
          "m"( *pw ): // input (%3)
          "cc" // clobbers
      );
  
      return rv;
  }
  
  class BOOST_SYMBOL_VISIBLE sp_counted_base
  {
  private:
  
      sp_counted_base( sp_counted_base const & );
      sp_counted_base & operator= ( sp_counted_base const & );
  
      int use_count_;        // #shared
      int weak_count_;       // #weak + (#shared != 0)
  
  public:
  
      sp_counted_base(): use_count_( 1 ), weak_count_( 1 )
      {
      }
  
      virtual ~sp_counted_base() // nothrow
      {
      }
  
      // dispose() is called when use_count_ drops to zero, to release
      // the resources managed by *this.
  
      virtual void dispose() = 0; // nothrow
  
      // destroy() is called when weak_count_ drops to zero.
  
      virtual void destroy() // nothrow
      {
          delete this;
      }
  
      virtual void * get_deleter( sp_typeinfo_ const & ti ) = 0;
      virtual void * get_local_deleter( sp_typeinfo_ const & ti ) = 0;
      virtual void * get_untyped_deleter() = 0;
  
      void add_ref_copy()
      {
          atomic_increment( &use_count_ );
      }
  
      bool add_ref_lock() // true on success
      {
          return atomic_conditional_increment( &use_count_ ) != 0;
      }
  
      void release() // nothrow
      {
          if( atomic_exchange_and_add( &use_count_, -1 ) == 1 )
          {
              dispose();
              weak_release();
          }
      }
  
      void weak_add_ref() // nothrow
      {
          atomic_increment( &weak_count_ );
      }
  
      void weak_release() // nothrow
      {
          if( atomic_exchange_and_add( &weak_count_, -1 ) == 1 )
          {
              destroy();
          }
      }
  
      long use_count() const // nothrow
      {
          return static_cast<int const volatile &>( use_count_ );
      }
  };
  
  } // namespace detail
  
  } // namespace lslboost
  
  #endif  // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_X86_HPP_INCLUDED
  