/******************************************************************************** Copyright (C) 1992-2006 Trolltech ASA. All rights reserved.**** This file is part of the QtCore module of the Qt Toolkit.**** This file may be used under the terms of the GNU General Public** License version 2.0 as published by the Free Software Foundation** and appearing in the file LICENSE.GPL included in the packaging of** this file.  Please review the following information to ensure GNU** General Public Licensing requirements will be met:** http://www.trolltech.com/products/qt/opensource.html**** If you are unsure which license is appropriate for your use, please** review the following information:** http://www.trolltech.com/products/qt/licensing.html or contact the** sales department at sales@trolltech.com.**** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.******************************************************************************/#include <qhash.h>#define UNLOCKED    {-1,-1,-1,-1}#define UNLOCKED2      UNLOCKED,UNLOCKED#define UNLOCKED4     UNLOCKED2,UNLOCKED2#define UNLOCKED8     UNLOCKED4,UNLOCKED4#define UNLOCKED16    UNLOCKED8,UNLOCKED8#define UNLOCKED32   UNLOCKED16,UNLOCKED16#define UNLOCKED64   UNLOCKED32,UNLOCKED32#define UNLOCKED128  UNLOCKED64,UNLOCKED64#define UNLOCKED256 UNLOCKED128,UNLOCKED128// use a 4k page for locksstatic int locks[256][4] = { UNLOCKED256 };int *getLock(volatile void *addr){ return locks[qHash(const_cast<void *>(addr)) % 256]; }static int *align16(int *lock){    ulong off = (((ulong) lock) % 16);    return off ? (int *)(ulong(lock) + 16 - off) : lock;}extern "C" {    int q_ldcw(volatile int *addr);    void q_atomic_lock(int *lock)    {        // ldcw requires a 16-byte aligned address        volatile int *x = align16(lock);        while (q_ldcw(x) == 0)	    ;    }    void q_atomic_unlock(int *lock)    { lock[0] = lock[1] = lock[2] = lock[3] = -1; }    int q_atomic_test_and_set_ptr(volatile void *ptr, void *expected, void *newval)    {	int *lock = getLock(ptr);	q_atomic_lock(lock);        if (*reinterpret_cast<void * volatile *>(ptr) == expected) {	    *reinterpret_cast<void * volatile *>(ptr) = newval;	    q_atomic_unlock(lock);	    return 1;        }	q_atomic_unlock(lock);	return 0;    }    void *q_atomic_set_ptr(volatile void *ptr, void *newval)    {        int *lock = getLock(ptr);	q_atomic_lock(lock);	void *oldval = *reinterpret_cast<void * volatile *>(ptr);        *reinterpret_cast<void * volatile *>(ptr) = newval;	q_atomic_unlock(lock);        return oldval;    }}