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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_untyped_deleter() = 0; | |
115 | ||
116 | void add_ref_copy() | |
117 | { | |
118 | atomic_increment( &use_count_ ); | |
119 | } | |
120 | ||
121 | bool add_ref_lock() // true on success | |
122 | { | |
123 | return atomic_conditional_increment( &use_count_ ) != 0; | |
124 | } | |
125 | ||
126 | void release() // nothrow | |
127 | { | |
128 | if( atomic_decrement( &use_count_ ) == 0 ) | |
129 | { | |
130 | dispose(); | |
131 | weak_release(); | |
132 | } | |
133 | } | |
134 | ||
135 | void weak_add_ref() // nothrow | |
136 | { | |
137 | atomic_increment( &weak_count_ ); | |
138 | } | |
139 | ||
140 | void weak_release() // nothrow | |
141 | { | |
142 | if( atomic_decrement( &weak_count_ ) == 0 ) | |
143 | { | |
144 | destroy(); | |
145 | } | |
146 | } | |
147 | ||
148 | long use_count() const // nothrow | |
149 | { | |
150 | return static_cast<int const volatile &>( use_count_ ); // TODO use ld.acq here | |
151 | } | |
152 | }; | |
153 | ||
154 | } // namespace detail | |
155 | ||
156 | } // namespace boost | |
157 | ||
158 | #endif // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_IA64_HPP_INCLUDED |