#ifndef BOOST_SMART_PTR_DETAIL_ATOMIC_COUNT_GCC_X86_HPP_INCLUDED | |
#define BOOST_SMART_PTR_DETAIL_ATOMIC_COUNT_GCC_X86_HPP_INCLUDED | |
// | |
// boost/detail/atomic_count_gcc_x86.hpp | |
// | |
// atomic_count for g++ on 486+/AMD64 | |
// | |
// Copyright 2007 Peter Dimov | |
// | |
// 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) | |
// | |
namespace boost | |
{ | |
namespace detail | |
{ | |
class atomic_count | |
{ | |
public: | |
explicit atomic_count( long v ) : value_( static_cast< int >( v ) ) {} | |
long operator++() | |
{ | |
return atomic_exchange_and_add( &value_, +1 ) + 1; | |
} | |
long operator--() | |
{ | |
return atomic_exchange_and_add( &value_, -1 ) - 1; | |
} | |
operator long() const | |
{ | |
return atomic_exchange_and_add( &value_, 0 ); | |
} | |
private: | |
atomic_count(atomic_count const &); | |
atomic_count & operator=(atomic_count const &); | |
mutable int value_; | |
private: | |
static int atomic_exchange_and_add( int * pw, int dv ) | |
{ | |
// int r = *pw; | |
// *pw += dv; | |
// return r; | |
int r; | |
__asm__ __volatile__ | |
( | |
"lock\n\t" | |
"xadd %1, %0": | |
"+m"( *pw ), "=r"( r ): // outputs (%0, %1) | |
"1"( dv ): // inputs (%2 == %1) | |
"memory", "cc" // clobbers | |
); | |
return r; | |
} | |
}; | |
} // namespace detail | |
} // namespace boost | |
#endif // #ifndef BOOST_SMART_PTR_DETAIL_ATOMIC_COUNT_GCC_X86_HPP_INCLUDED |