/****************************************************************************
**
** Copyright (C) 2001-2004 NovodeX AG.
** Copyright (C) 2004-2008 AGEIA Technologies, Inc.
** Copyright (C) 2008-2013 NVIDIA Corporation.
** Copyright (C) 2017 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
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** This file is part of Qt 3D Studio.
**
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** Alternatively, this file may be used under the terms of the GNU
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** the Free Software Foundation and appearing in the file LICENSE.GPL3
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#include "foundation/Qt3DS.h"
#include "foundation/Qt3DSAtomic.h"

#define PAUSE() asm("nop")

namespace qt3ds {
namespace foundation {

    void *atomicCompareExchangePointer(volatile void **dest, void *exch, void *comp)
    {
        return __sync_val_compare_and_swap((void **)dest, comp, exch);
    }

    QT3DSI32 atomicCompareExchange(volatile QT3DSI32 *dest, QT3DSI32 exch, QT3DSI32 comp)
    {
        return __sync_val_compare_and_swap(dest, comp, exch);
    }

    QT3DSI32 atomicIncrement(volatile QT3DSI32 *val) { return __sync_add_and_fetch(val, 1); }

    QT3DSI32 atomicDecrement(volatile QT3DSI32 *val) { return __sync_sub_and_fetch(val, 1); }

    QT3DSI32 atomicAdd(volatile QT3DSI32 *val, QT3DSI32 delta) { return __sync_add_and_fetch(val, delta); }

    QT3DSI32 atomicMax(volatile QT3DSI32 *val, QT3DSI32 val2)
    {
        QT3DSI32 oldVal, newVal;

        do {
            PAUSE();
            oldVal = *val;

            if (val2 > oldVal)
                newVal = val2;
            else
                newVal = oldVal;

        } while (atomicCompareExchange(val, newVal, oldVal) != oldVal);

        return *val;
    }

    QT3DSI32 atomicExchange(volatile QT3DSI32 *val, QT3DSI32 val2)
    {
        QT3DSI32 newVal, oldVal;

        do {
            PAUSE();
            oldVal = *val;
            newVal = val2;
        } while (atomicCompareExchange(val, newVal, oldVal) != oldVal);

        return oldVal;
    }

} // namespace foundation
} // namespace qt3ds