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/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see http://www.qt.io/terms-conditions. For further
** information use the contact form at http://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 or version 3 as published by the Free
** Software Foundation and appearing in the file LICENSE.LGPLv21 and
** LICENSE.LGPLv3 included in the packaging of this file. Please review the
** following information to ensure the GNU Lesser General Public License
** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** As a special exception, The Qt Company gives you certain additional
** rights. These rights are described in The Qt Company LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 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 the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include <QtCore/qglobal.h>
#include <QtCore/qhash.h>
QT_BEGIN_NAMESPACE
QT_USE_NAMESPACE
#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 locks
static 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; }
}
QT_END_NAMESPACE
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