/****************************************************************************
**
** Copyright (C) 1992-2004 Trolltech AS. All rights reserved.
**
** This file is part of the core module of the Qt Toolkit.
**
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** as defined by Trolltech AS of Norway and appearing in the file
** LICENSE.QPL included in the packaging of this file.
**
** This file may be distributed and/or modified under the terms of the
** GNU General Public License version 2 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.
**
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**   information about Qt Commercial License Agreements.
** See http://www.trolltech.com/qpl/ for QPL licensing information.
** See http://www.trolltech.com/gpl/ for GPL licensing information.
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****************************************************************************/

#ifndef BOUNDSCHECKER_QATOMIC_H
#define BOUNDSCHECKER_QATOMIC_H

#include <qglobal.h>

__forceinline int q_atomic_xchg(int newval)
{
    static int lockvar = 0;
    int *pointer = &lockvar;

    __asm {
        mov EDX,pointer
        mov ECX,newval
        xchg dword ptr[EDX],ECX
        mov newval,ECX
    }
    return newval;
}

inline void q_atomic_lock()
{
    while (q_atomic_xchg(~0) != 0)
        ;
}

inline void q_atomic_unlock()
{
    q_atomic_xchg(0);
}

inline int q_atomic_test_and_set_int(volatile int *pointer, int expected, int newval)
{
    q_atomic_lock();
    if (*pointer == expected) {
        *pointer = newval;
        q_atomic_unlock();
        return 1;
    }
    q_atomic_unlock();
    return 0;
}

inline int q_atomic_test_and_set_ptr(volatile void *pointer, void *expected, void *newval)
{
    q_atomic_lock();
    if (*reinterpret_cast<void * volatile *>(pointer) == expected) {
        *reinterpret_cast<void * volatile *>(pointer) = newval;
        q_atomic_unlock();
        return 1;
    }
    q_atomic_unlock();
    return 0;
}

inline int q_atomic_increment(volatile int *pointer)
{
    q_atomic_lock();
    int ret = ++(*pointer);
    q_atomic_unlock();
    return ret;
}

inline int q_atomic_decrement(volatile int *pointer)
{
    q_atomic_lock();
    int ret = --(*pointer);
    q_atomic_unlock();
    return ret;
}

inline int q_atomic_set_int(volatile int *pointer, int newval)
{
    q_atomic_lock();
    int ret = *pointer;
    *pointer = newval;
    q_atomic_unlock();
    return ret;
}

inline void *q_atomic_set_ptr(volatile void *pointer, void *newval)
{
    q_atomic_lock();
    void *ret = *reinterpret_cast<void * volatile *>(pointer);
    *reinterpret_cast<void * volatile *>(pointer) = newval;
    q_atomic_unlock();
    return ret;

}

#endif // BOUNDSCHECKER_QATOMIC_H
