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src/boost/smart_ptr/detail/sp_counted_base_gcc_x86.hpp  view on Meta::CPAN

#ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_X86_HPP_INCLUDED
#define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_X86_HPP_INCLUDED

// MS compatible compilers support #pragma once

#if defined(_MSC_VER) && (_MSC_VER >= 1020)
# pragma once
#endif

//
//  detail/sp_counted_base_gcc_x86.hpp - g++ on 486+ or AMD64
//
//  Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
//  Copyright 2004-2005 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)
//
//
//  Lock-free algorithm by Alexander Terekhov
//
//  Thanks to Ben Hitchings for the #weak + (#shared != 0)
//  formulation
//

#include <boost/detail/sp_typeinfo.hpp>

namespace boost
{

namespace detail
{

inline 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)
        "m"( *pw ), "1"( dv ): // inputs (%2, %3 == %1)
        "memory", "cc" // clobbers
    );

    return r;
}

inline void atomic_increment( int * pw )
{
    //atomic_exchange_and_add( pw, 1 );

    __asm__
    (
        "lock\n\t"
        "incl %0":
        "=m"( *pw ): // output (%0)
        "m"( *pw ): // input (%1)
        "cc" // clobbers
    );
}

inline int atomic_conditional_increment( int * pw )
{
    // int rv = *pw;
    // if( rv != 0 ) ++*pw;
    // return rv;

    int rv, tmp;

    __asm__
    (
        "movl %0, %%eax\n\t"
        "0:\n\t"
        "test %%eax, %%eax\n\t"
        "je 1f\n\t"
        "movl %%eax, %2\n\t"
        "incl %2\n\t"