ceph/src/boost/libs/smart_ptr/include/boost/smart_ptr/detail/sp_counted_base_gcc_ppc.hpp

   1 #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_PPC_HPP_INCLUDED
   2 #define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_PPC_HPP_INCLUDED
   3
   4 // MS compatible compilers support #pragma once
   5
   6 #if defined(_MSC_VER) && (_MSC_VER >= 1020)
   7 # pragma once
   8 #endif
   9
  10 //
  11 //  detail/sp_counted_base_gcc_ppc.hpp - g++ on PowerPC
  12 //
  13 //  Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
  14 //  Copyright 2004-2005 Peter Dimov
  15 //
  16 //  Distributed under the Boost Software License, Version 1.0. (See
  17 //  accompanying file LICENSE_1_0.txt or copy at
  18 //  http://www.boost.org/LICENSE_1_0.txt)
  19 //
  20 //
  21 //  Lock-free algorithm by Alexander Terekhov
  22 //
  23 //  Thanks to Ben Hitchings for the #weak + (#shared != 0)
  24 //  formulation
  25 //
  26
  27 #include <boost/detail/sp_typeinfo.hpp>
  28
  29 namespace boost
  30 {
  31
  32 namespace detail
  33 {
  34
  35 inline void atomic_increment( int * pw )
  36 {
  37     // ++*pw;
  38
  39     int tmp;
  40
  41     __asm__
  42     (
  43         "0:\n\t"
  44         "lwarx %1, 0, %2\n\t"
  45         "addi %1, %1, 1\n\t"
  46         "stwcx. %1, 0, %2\n\t"
  47         "bne- 0b":
  48
  49         "=m"( *pw ), "=&b"( tmp ):
  50         "r"( pw ), "m"( *pw ):
  51         "cc"
  52     );
  53 }
  54
  55 inline int atomic_decrement( int * pw )
  56 {
  57     // return --*pw;
  58
  59     int rv;
  60
  61     __asm__ __volatile__
  62     (
  63         "sync\n\t"
  64         "0:\n\t"
  65         "lwarx %1, 0, %2\n\t"
  66         "addi %1, %1, -1\n\t"
  67         "stwcx. %1, 0, %2\n\t"
  68         "bne- 0b\n\t"
  69         "isync":
  70
  71         "=m"( *pw ), "=&b"( rv ):
  72         "r"( pw ), "m"( *pw ):
  73         "memory", "cc"
  74     );
  75
  76     return rv;
  77 }
  78
  79 inline int atomic_conditional_increment( int * pw )
  80 {
  81     // if( *pw != 0 ) ++*pw;
  82     // return *pw;
  83
  84     int rv;
  85
  86     __asm__
  87     (
  88         "0:\n\t"
  89         "lwarx %1, 0, %2\n\t"
  90         "cmpwi %1, 0\n\t"
  91         "beq 1f\n\t"
  92         "addi %1, %1, 1\n\t"
  93         "1:\n\t"
  94         "stwcx. %1, 0, %2\n\t"
  95         "bne- 0b":
  96
  97         "=m"( *pw ), "=&b"( rv ):
  98         "r"( pw ), "m"( *pw ):
  99         "cc"
 100     );
 101
 102     return rv;
 103 }
 104
 105 class sp_counted_base
 106 {
 107 private:
 108
 109     sp_counted_base( sp_counted_base const & );
 110     sp_counted_base & operator= ( sp_counted_base const & );
 111
 112     int use_count_;        // #shared
 113     int weak_count_;       // #weak + (#shared != 0)
 114
 115 public:
 116
 117     sp_counted_base(): use_count_( 1 ), weak_count_( 1 )
 118     {
 119     }
 120
 121     virtual ~sp_counted_base() // nothrow
 122     {
 123     }
 124
 125     // dispose() is called when use_count_ drops to zero, to release
 126     // the resources managed by *this.
 127
 128     virtual void dispose() = 0; // nothrow
 129
 130     // destroy() is called when weak_count_ drops to zero.
 131
 132     virtual void destroy() // nothrow
 133     {
 134         delete this;
 135     }
 136
 137     virtual void * get_deleter( sp_typeinfo const & ti ) = 0;
 138     virtual void * get_untyped_deleter() = 0;
 139
 140     void add_ref_copy()
 141     {
 142         atomic_increment( &use_count_ );
 143     }
 144
 145     bool add_ref_lock() // true on success
 146     {
 147         return atomic_conditional_increment( &use_count_ ) != 0;
 148     }
 149
 150     void release() // nothrow
 151     {
 152         if( atomic_decrement( &use_count_ ) == 0 )
 153         {
 154             dispose();
 155             weak_release();
 156         }
 157     }
 158
 159     void weak_add_ref() // nothrow
 160     {
 161         atomic_increment( &weak_count_ );
 162     }
 163
 164     void weak_release() // nothrow
 165     {
 166         if( atomic_decrement( &weak_count_ ) == 0 )
 167         {
 168             destroy();
 169         }
 170     }
 171
 172     long use_count() const // nothrow
 173     {
 174         return static_cast<int const volatile &>( use_count_ );
 175     }
 176 };
 177
 178 } // namespace detail
 179
 180 } // namespace boost
 181
 182 #endif  // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_PPC_HPP_INCLUDED