williamr@2: #ifndef BOOST_DETAIL_SP_COUNTED_BASE_GCC_IA64_HPP_INCLUDED
williamr@2: #define BOOST_DETAIL_SP_COUNTED_BASE_GCC_IA64_HPP_INCLUDED
williamr@2: 
williamr@2: //
williamr@2: //  detail/sp_counted_base_gcc_ia64.hpp - g++ on IA64
williamr@2: //
williamr@2: //  Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
williamr@2: //  Copyright 2004-2006 Peter Dimov
williamr@2: //  Copyright 2005 Ben Hutchings
williamr@2: //
williamr@2: //  Distributed under the Boost Software License, Version 1.0. (See
williamr@2: //  accompanying file LICENSE_1_0.txt or copy at
williamr@2: //  http://www.boost.org/LICENSE_1_0.txt)
williamr@2: //
williamr@2: //
williamr@2: //  Lock-free algorithm by Alexander Terekhov
williamr@2: //
williamr@2: 
williamr@2: #include <typeinfo>
williamr@2: 
williamr@2: namespace boost
williamr@2: {
williamr@2: 
williamr@2: namespace detail
williamr@2: {
williamr@2: 
williamr@2: inline void atomic_increment( int * pw )
williamr@2: {
williamr@2:     // ++*pw;
williamr@2: 
williamr@2:     int tmp;
williamr@2: 
williamr@2:     // No barrier is required here but fetchadd always has an acquire or
williamr@2:     // release barrier associated with it.  We choose release as it should be
williamr@2:     // cheaper.
williamr@2:     __asm__ ("fetchadd4.rel %0=%1,1" :
williamr@2:          "=r"(tmp), "=m"(*pw) :
williamr@2:          "m"( *pw ));
williamr@2: }
williamr@2: 
williamr@2: inline int atomic_decrement( int * pw )
williamr@2: {
williamr@2:     // return --*pw;
williamr@2: 
williamr@2:     int rv;
williamr@2: 
williamr@2:     __asm__ ("     fetchadd4.rel %0=%1,-1 ;; \n"
williamr@2:              "     cmp.eq        p7,p0=1,%0 ;; \n"
williamr@2:              "(p7) ld4.acq       %0=%1    " :
williamr@2:              "=&r"(rv), "=m"(*pw) :
williamr@2:              "m"( *pw ) :
williamr@2:              "p7");
williamr@2: 
williamr@2:     return rv;
williamr@2: }
williamr@2: 
williamr@2: inline int atomic_conditional_increment( int * pw )
williamr@2: {
williamr@2:     // if( *pw != 0 ) ++*pw;
williamr@2:     // return *pw;
williamr@2: 
williamr@2:     int rv, tmp, tmp2;
williamr@2: 
williamr@2:     __asm__ ("0:   ld4          %0=%3           ;; \n"
williamr@2:          "     cmp.eq       p7,p0=0,%0        ;; \n"
williamr@2:          "(p7) br.cond.spnt 1f                \n"
williamr@2:          "     mov          ar.ccv=%0         \n"
williamr@2:          "     add          %1=1,%0           ;; \n"
williamr@2:          "     cmpxchg4.acq %2=%3,%1,ar.ccv ;; \n"
williamr@2:          "     cmp.ne       p7,p0=%0,%2       ;; \n"
williamr@2:          "(p7) br.cond.spnt 0b                \n"
williamr@2:          "     mov          %0=%1             ;; \n"
williamr@2:          "1:" : 
williamr@2:          "=&r"(rv), "=&r"(tmp), "=&r"(tmp2), "=m"(*pw) :
williamr@2:          "m"( *pw ) :
williamr@2:          "ar.ccv", "p7");
williamr@2: 
williamr@2:     return rv;
williamr@2: }
williamr@2: 
williamr@2: class sp_counted_base
williamr@2: {
williamr@2: private:
williamr@2: 
williamr@2:     sp_counted_base( sp_counted_base const & );
williamr@2:     sp_counted_base & operator= ( sp_counted_base const & );
williamr@2: 
williamr@2:     int use_count_;        // #shared
williamr@2:     int weak_count_;       // #weak + (#shared != 0)
williamr@2: 
williamr@2: public:
williamr@2: 
williamr@2:     sp_counted_base(): use_count_( 1 ), weak_count_( 1 )
williamr@2:     {
williamr@2:     }
williamr@2: 
williamr@2:     virtual ~sp_counted_base() // nothrow
williamr@2:     {
williamr@2:     }
williamr@2: 
williamr@2:     // dispose() is called when use_count_ drops to zero, to release
williamr@2:     // the resources managed by *this.
williamr@2: 
williamr@2:     virtual void dispose() = 0; // nothrow
williamr@2: 
williamr@2:     // destroy() is called when weak_count_ drops to zero.
williamr@2: 
williamr@2:     virtual void destroy() // nothrow
williamr@2:     {
williamr@2:         delete this;
williamr@2:     }
williamr@2: 
williamr@2:     virtual void * get_deleter( std::type_info const & ti ) = 0;
williamr@2: 
williamr@2:     void add_ref_copy()
williamr@2:     {
williamr@2:         atomic_increment( &use_count_ );
williamr@2:     }
williamr@2: 
williamr@2:     bool add_ref_lock() // true on success
williamr@2:     {
williamr@2:         return atomic_conditional_increment( &use_count_ ) != 0;
williamr@2:     }
williamr@2: 
williamr@2:     void release() // nothrow
williamr@2:     {
williamr@2:         if( atomic_decrement( &use_count_ ) == 0 )
williamr@2:         {
williamr@2:             dispose();
williamr@2:             weak_release();
williamr@2:         }
williamr@2:     }
williamr@2: 
williamr@2:     void weak_add_ref() // nothrow
williamr@2:     {
williamr@2:         atomic_increment( &weak_count_ );
williamr@2:     }
williamr@2: 
williamr@2:     void weak_release() // nothrow
williamr@2:     {
williamr@2:         if( atomic_decrement( &weak_count_ ) == 0 )
williamr@2:         {
williamr@2:             destroy();
williamr@2:         }
williamr@2:     }
williamr@2: 
williamr@2:     long use_count() const // nothrow
williamr@2:     {
williamr@2:         return static_cast<int const volatile &>( use_count_ ); // TODO use ld.acq here
williamr@2:     }
williamr@2: };
williamr@2: 
williamr@2: } // namespace detail
williamr@2: 
williamr@2: } // namespace boost
williamr@2: 
williamr@2: #endif  // #ifndef BOOST_DETAIL_SP_COUNTED_BASE_GCC_IA64_HPP_INCLUDED