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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 |