#ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_IA64_HPP_INCLUDED | |
#define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_IA64_HPP_INCLUDED | |
// | |
// detail/sp_counted_base_gcc_ia64.hpp - g++ on IA64 | |
// | |
// Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd. | |
// Copyright 2004-2006 Peter Dimov | |
// Copyright 2005 Ben Hutchings | |
// | |
// Distributed under the Boost Software License, Version 1.0. (See | |
// accompanying file LICENSE_1_0.txt or copy at | |
// http://www.boost.org/LICENSE_1_0.txt) | |
// | |
// | |
// Lock-free algorithm by Alexander Terekhov | |
// | |
#include <boost/detail/sp_typeinfo.hpp> | |
namespace boost | |
{ | |
namespace detail | |
{ | |
inline void atomic_increment( int * pw ) | |
{ | |
// ++*pw; | |
int tmp; | |
// No barrier is required here but fetchadd always has an acquire or | |
// release barrier associated with it. We choose release as it should be | |
// cheaper. | |
__asm__ ("fetchadd4.rel %0=%1,1" : | |
"=r"(tmp), "=m"(*pw) : | |
"m"( *pw )); | |
} | |
inline int atomic_decrement( int * pw ) | |
{ | |
// return --*pw; | |
int rv; | |
__asm__ (" fetchadd4.rel %0=%1,-1 ;; \n" | |
" cmp.eq p7,p0=1,%0 ;; \n" | |
"(p7) ld4.acq %0=%1 " : | |
"=&r"(rv), "=m"(*pw) : | |
"m"( *pw ) : | |
"p7"); | |
return rv; | |
} | |
inline int atomic_conditional_increment( int * pw ) | |
{ | |
// if( *pw != 0 ) ++*pw; | |
// return *pw; | |
int rv, tmp, tmp2; | |
__asm__ ("0: ld4 %0=%3 ;; \n" | |
" cmp.eq p7,p0=0,%0 ;; \n" | |
"(p7) br.cond.spnt 1f \n" | |
" mov ar.ccv=%0 \n" | |
" add %1=1,%0 ;; \n" | |
" cmpxchg4.acq %2=%3,%1,ar.ccv ;; \n" | |
" cmp.ne p7,p0=%0,%2 ;; \n" | |
"(p7) br.cond.spnt 0b \n" | |
" mov %0=%1 ;; \n" | |
"1:" : | |
"=&r"(rv), "=&r"(tmp), "=&r"(tmp2), "=m"(*pw) : | |
"m"( *pw ) : | |
"ar.ccv", "p7"); | |
return rv; | |
} | |
class sp_counted_base | |
{ | |
private: | |
sp_counted_base( sp_counted_base const & ); | |
sp_counted_base & operator= ( sp_counted_base const & ); | |
int use_count_; // #shared | |
int weak_count_; // #weak + (#shared != 0) | |
public: | |
sp_counted_base(): use_count_( 1 ), weak_count_( 1 ) | |
{ | |
} | |
virtual ~sp_counted_base() // nothrow | |
{ | |
} | |
// dispose() is called when use_count_ drops to zero, to release | |
// the resources managed by *this. | |
virtual void dispose() = 0; // nothrow | |
// destroy() is called when weak_count_ drops to zero. | |
virtual void destroy() // nothrow | |
{ | |
delete this; | |
} | |
virtual void * get_deleter( sp_typeinfo const & ti ) = 0; | |
void add_ref_copy() | |
{ | |
atomic_increment( &use_count_ ); | |
} | |
bool add_ref_lock() // true on success | |
{ | |
return atomic_conditional_increment( &use_count_ ) != 0; | |
} | |
void release() // nothrow | |
{ | |
if( atomic_decrement( &use_count_ ) == 0 ) | |
{ | |
dispose(); | |
weak_release(); | |
} | |
} | |
void weak_add_ref() // nothrow | |
{ | |
atomic_increment( &weak_count_ ); | |
} | |
void weak_release() // nothrow | |
{ | |
if( atomic_decrement( &weak_count_ ) == 0 ) | |
{ | |
destroy(); | |
} | |
} | |
long use_count() const // nothrow | |
{ | |
return static_cast<int const volatile &>( use_count_ ); // TODO use ld.acq here | |
} | |
}; | |
} // namespace detail | |
} // namespace boost | |
#endif // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_IA64_HPP_INCLUDED |