#ifndef BOOST_DETAIL_SP_COUNTED_BASE_GCC_IA64_HPP_INCLUDED

#define BOOST_DETAIL_SP_COUNTED_BASE_GCC_IA64_HPP_INCLUDED

//

//  detail/sp_counted_base_gcc_ia64.hpp - g++ on IA64

//

//  Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.

//  Copyright 2004-2006 Peter Dimov

//  Copyright 2005 Ben Hutchings

//

//  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

//

#include <typeinfo>

namespace boost

{

namespace detail

{

inline void atomic_increment( int * pw )

{

    // ++*pw;

    int tmp;

    // No barrier is required here but fetchadd always has an acquire or

    // release barrier associated with it.  We choose release as it should be

    // cheaper.

    __asm__ ("fetchadd4.rel %0=%1,1" :

         "=r"(tmp), "=m"(*pw) :

         "m"( *pw ));

}

inline int atomic_decrement( int * pw )

{

    // return --*pw;

    int rv;

    __asm__ ("     fetchadd4.rel %0=%1,-1 ;; \n"

             "     cmp.eq        p7,p0=1,%0 ;; \n"

             "(p7) ld4.acq       %0=%1    " :

             "=&r"(rv), "=m"(*pw) :

             "m"( *pw ) :

             "p7");

    return rv;

}

inline int atomic_conditional_increment( int * pw )

{

    // if( *pw != 0 ) ++*pw;

    // return *pw;

    int rv, tmp, tmp2;

    __asm__ ("0:   ld4          %0=%3           ;; \n"

         "     cmp.eq       p7,p0=0,%0        ;; \n"

         "(p7) br.cond.spnt 1f                \n"

         "     mov          ar.ccv=%0         \n"

         "     add          %1=1,%0           ;; \n"

         "     cmpxchg4.acq %2=%3,%1,ar.ccv ;; \n"

         "     cmp.ne       p7,p0=%0,%2       ;; \n"

         "(p7) br.cond.spnt 0b                \n"

         "     mov          %0=%1             ;; \n"

         "1:" : 

         "=&r"(rv), "=&r"(tmp), "=&r"(tmp2), "=m"(*pw) :

         "m"( *pw ) :

         "ar.ccv", "p7");

    return rv;

}

class 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( std::type_info const & ti ) = 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_decrement( &use_count_ ) == 0 )

        {

            dispose();

            weak_release();

        }

    }

    void weak_add_ref() // nothrow

    {

        atomic_increment( &weak_count_ );

    }

    void weak_release() // nothrow

    {

        if( atomic_decrement( &weak_count_ ) == 0 )

        {

            destroy();

        }

    }

    long use_count() const // nothrow

    {

        return static_cast<int const volatile &>( use_count_ ); // TODO use ld.acq here

    }

};

} // namespace detail

} // namespace boost

#endif  // #ifndef BOOST_DETAIL_SP_COUNTED_BASE_GCC_IA64_HPP_INCLUDED