smart_ptr/detail/sp_counted_base_gcc_ia64.hpp

0001 #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_IA64_HPP_INCLUDED
0002 #define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_IA64_HPP_INCLUDED
0003
0004 //
0005 //  detail/sp_counted_base_gcc_ia64.hpp - g++ on IA64
0006 //
0007 //  Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
0008 //  Copyright 2004-2006 Peter Dimov
0009 //  Copyright 2005 Ben Hutchings
0010 //
0011 //  Distributed under the Boost Software License, Version 1.0. (See
0012 //  accompanying file LICENSE_1_0.txt or copy at
0013 //  http://www.boost.org/LICENSE_1_0.txt)
0014 //
0015 //
0016 //  Lock-free algorithm by Alexander Terekhov
0017 //
0018
0019 #include <boost/smart_ptr/detail/sp_typeinfo_.hpp>
0020 #include <boost/smart_ptr/detail/sp_obsolete.hpp>
0021 #include <boost/config.hpp>
0022
0023 #if defined(BOOST_SP_REPORT_IMPLEMENTATION)
0024
0025 #include <boost/config/pragma_message.hpp>
0026 BOOST_PRAGMA_MESSAGE("Using g++/IA64 sp_counted_base")
0027
0028 #endif
0029
0030 BOOST_SP_OBSOLETE()
0031
0032 namespace boost
0033 {
0034
0035 namespace detail
0036 {
0037
0038 inline void atomic_increment( int * pw )
0039 {
0040     // ++*pw;
0041
0042     int tmp;
0043
0044     // No barrier is required here but fetchadd always has an acquire or
0045     // release barrier associated with it.  We choose release as it should be
0046     // cheaper.
0047     __asm__ ("fetchadd4.rel %0=%1,1" :
0048          "=r"(tmp), "=m"(*pw) :
0049          "m"( *pw ));
0050 }
0051
0052 inline int atomic_decrement( int * pw )
0053 {
0054     // return --*pw;
0055
0056     int rv;
0057
0058     __asm__ ("     fetchadd4.rel %0=%1,-1 ;; \n"
0059              "     cmp.eq        p7,p0=1,%0 ;; \n"
0060              "(p7) ld4.acq       %0=%1    " :
0061              "=&r"(rv), "=m"(*pw) :
0062              "m"( *pw ) :
0063              "p7");
0064
0065     return rv;
0066 }
0067
0068 inline int atomic_conditional_increment( int * pw )
0069 {
0070     // if( *pw != 0 ) ++*pw;
0071     // return *pw;
0072
0073     int rv, tmp, tmp2;
0074
0075     __asm__ ("0:   ld4          %0=%3           ;; \n"
0076          "     cmp.eq       p7,p0=0,%0        ;; \n"
0077          "(p7) br.cond.spnt 1f                \n"
0078          "     mov          ar.ccv=%0         \n"
0079          "     add          %1=1,%0           ;; \n"
0080          "     cmpxchg4.acq %2=%3,%1,ar.ccv ;; \n"
0081          "     cmp.ne       p7,p0=%0,%2       ;; \n"
0082          "(p7) br.cond.spnt 0b                \n"
0083          "     mov          %0=%1             ;; \n"
0084          "1:" :
0085          "=&r"(rv), "=&r"(tmp), "=&r"(tmp2), "=m"(*pw) :
0086          "m"( *pw ) :
0087          "ar.ccv", "p7");
0088
0089     return rv;
0090 }
0091
0092 class BOOST_SYMBOL_VISIBLE sp_counted_base
0093 {
0094 private:
0095
0096     sp_counted_base( sp_counted_base const & );
0097     sp_counted_base & operator= ( sp_counted_base const & );
0098
0099     int use_count_;        // #shared
0100     int weak_count_;       // #weak + (#shared != 0)
0101
0102 public:
0103
0104     sp_counted_base(): use_count_( 1 ), weak_count_( 1 )
0105     {
0106     }
0107
0108     virtual ~sp_counted_base() // nothrow
0109     {
0110     }
0111
0112     // dispose() is called when use_count_ drops to zero, to release
0113     // the resources managed by *this.
0114
0115     virtual void dispose() = 0; // nothrow
0116
0117     // destroy() is called when weak_count_ drops to zero.
0118
0119     virtual void destroy() // nothrow
0120     {
0121         delete this;
0122     }
0123
0124     virtual void * get_deleter( sp_typeinfo_ const & ti ) = 0;
0125     virtual void * get_local_deleter( sp_typeinfo_ const & ti ) = 0;
0126     virtual void * get_untyped_deleter() = 0;
0127
0128     void add_ref_copy()
0129     {
0130         atomic_increment( &use_count_ );
0131     }
0132
0133     bool add_ref_lock() // true on success
0134     {
0135         return atomic_conditional_increment( &use_count_ ) != 0;
0136     }
0137
0138     void release() // nothrow
0139     {
0140         if( atomic_decrement( &use_count_ ) == 0 )
0141         {
0142             dispose();
0143             weak_release();
0144         }
0145     }
0146
0147     void weak_add_ref() // nothrow
0148     {
0149         atomic_increment( &weak_count_ );
0150     }
0151
0152     void weak_release() // nothrow
0153     {
0154         if( atomic_decrement( &weak_count_ ) == 0 )
0155         {
0156             destroy();
0157         }
0158     }
0159
0160     long use_count() const // nothrow
0161     {
0162         return static_cast<int const volatile &>( use_count_ ); // TODO use ld.acq here
0163     }
0164 };
0165
0166 } // namespace detail
0167
0168 } // namespace boost
0169
0170 #endif  // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_IA64_HPP_INCLUDED