ceph/src/boost/boost/smart_ptr/detail/sp_counted_base_gcc_ia64.hpp

   1 #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_IA64_HPP_INCLUDED
   2 #define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_IA64_HPP_INCLUDED
   3
   4 //
   5 //  detail/sp_counted_base_gcc_ia64.hpp - g++ on IA64
   6 //
   7 //  Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
   8 //  Copyright 2004-2006 Peter Dimov
   9 //  Copyright 2005 Ben Hutchings
  10 //
  11 //  Distributed under the Boost Software License, Version 1.0. (See
  12 //  accompanying file LICENSE_1_0.txt or copy at
  13 //  http://www.boost.org/LICENSE_1_0.txt)
  14 //
  15 //
  16 //  Lock-free algorithm by Alexander Terekhov
  17 //
  18
  19 #include <boost/detail/sp_typeinfo.hpp>
  20
  21 namespace boost
  22 {
  23
  24 namespace detail
  25 {
  26
  27 inline void atomic_increment( int * pw )
  28 {
  29     // ++*pw;
  30
  31     int tmp;
  32
  33     // No barrier is required here but fetchadd always has an acquire or
  34     // release barrier associated with it.  We choose release as it should be
  35     // cheaper.
  36     __asm__ ("fetchadd4.rel %0=%1,1" :
  37          "=r"(tmp), "=m"(*pw) :
  38          "m"( *pw ));
  39 }
  40
  41 inline int atomic_decrement( int * pw )
  42 {
  43     // return --*pw;
  44
  45     int rv;
  46
  47     __asm__ ("     fetchadd4.rel %0=%1,-1 ;; \n"
  48              "     cmp.eq        p7,p0=1,%0 ;; \n"
  49              "(p7) ld4.acq       %0=%1    " :
  50              "=&r"(rv), "=m"(*pw) :
  51              "m"( *pw ) :
  52              "p7");
  53
  54     return rv;
  55 }
  56
  57 inline int atomic_conditional_increment( int * pw )
  58 {
  59     // if( *pw != 0 ) ++*pw;
  60     // return *pw;
  61
  62     int rv, tmp, tmp2;
  63
  64     __asm__ ("0:   ld4          %0=%3           ;; \n"
  65          "     cmp.eq       p7,p0=0,%0        ;; \n"
  66          "(p7) br.cond.spnt 1f                \n"
  67          "     mov          ar.ccv=%0         \n"
  68          "     add          %1=1,%0           ;; \n"
  69          "     cmpxchg4.acq %2=%3,%1,ar.ccv ;; \n"
  70          "     cmp.ne       p7,p0=%0,%2       ;; \n"
  71          "(p7) br.cond.spnt 0b                \n"
  72          "     mov          %0=%1             ;; \n"
  73          "1:" :
  74          "=&r"(rv), "=&r"(tmp), "=&r"(tmp2), "=m"(*pw) :
  75          "m"( *pw ) :
  76          "ar.ccv", "p7");
  77
  78     return rv;
  79 }
  80
  81 class sp_counted_base
  82 {
  83 private:
  84
  85     sp_counted_base( sp_counted_base const & );
  86     sp_counted_base & operator= ( sp_counted_base const & );
  87
  88     int use_count_;        // #shared
  89     int weak_count_;       // #weak + (#shared != 0)
  90
  91 public:
  92
  93     sp_counted_base(): use_count_( 1 ), weak_count_( 1 )
  94     {
  95     }
  96
  97     virtual ~sp_counted_base() // nothrow
  98     {
  99     }
 100
 101     // dispose() is called when use_count_ drops to zero, to release
 102     // the resources managed by *this.
 103
 104     virtual void dispose() = 0; // nothrow
 105
 106     // destroy() is called when weak_count_ drops to zero.
 107
 108     virtual void destroy() // nothrow
 109     {
 110         delete this;
 111     }
 112
 113     virtual void * get_deleter( sp_typeinfo const & ti ) = 0;
 114     virtual void * get_local_deleter( sp_typeinfo const & ti ) = 0;
 115     virtual void * get_untyped_deleter() = 0;
 116
 117     void add_ref_copy()
 118     {
 119         atomic_increment( &use_count_ );
 120     }
 121
 122     bool add_ref_lock() // true on success
 123     {
 124         return atomic_conditional_increment( &use_count_ ) != 0;
 125     }
 126
 127     void release() // nothrow
 128     {
 129         if( atomic_decrement( &use_count_ ) == 0 )
 130         {
 131             dispose();
 132             weak_release();
 133         }
 134     }
 135
 136     void weak_add_ref() // nothrow
 137     {
 138         atomic_increment( &weak_count_ );
 139     }
 140
 141     void weak_release() // nothrow
 142     {
 143         if( atomic_decrement( &weak_count_ ) == 0 )
 144         {
 145             destroy();
 146         }
 147     }
 148
 149     long use_count() const // nothrow
 150     {
 151         return static_cast<int const volatile &>( use_count_ ); // TODO use ld.acq here
 152     }
 153 };
 154
 155 } // namespace detail
 156
 157 } // namespace boost
 158
 159 #endif  // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_IA64_HPP_INCLUDED