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Contents
#ifndef BOOST_DETAIL_ATOMIC_COUNT_GCC_X86_HPP_INCLUDED
#define BOOST_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 ) ) {}
void operator++()
{
__asm__
(
"lock\n\t"
"incl %0":
"+m"( value_ ): // output (%0)
: // inputs
"cc" // clobbers
);
}
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_DETAIL_ATOMIC_COUNT_SYNC_HPP_INCLUDED
Version data entries
30 entries across 30 versions & 5 rubygems