/* $Id: thread-r0drv-nt.cpp 13262 2008-10-14 13:09:04Z vboxsync $ */
/** @file
 * IPRT - Threads, Ring-0 Driver, NT.
 */

/*
 * Copyright (C) 2006-2007 Sun Microsystems, Inc.
 *
 * This file is part of VirtualBox Open Source Edition (OSE), as
 * available from http://www.virtualbox.org. This file is free software;
 * you can redistribute it and/or modify it under the terms of the GNU
 * General Public License (GPL) as published by the Free Software
 * Foundation, in version 2 as it comes in the "COPYING" file of the
 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
 *
 * The contents of this file may alternatively be used under the terms
 * of the Common Development and Distribution License Version 1.0
 * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
 * VirtualBox OSE distribution, in which case the provisions of the
 * CDDL are applicable instead of those of the GPL.
 *
 * You may elect to license modified versions of this file under the
 * terms and conditions of either the GPL or the CDDL or both.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
 * Clara, CA 95054 USA or visit http://www.sun.com if you need
 * additional information or have any questions.
 */

/*******************************************************************************
*   Header Files                                                               *
*******************************************************************************/
#include "the-nt-kernel.h"

#include <iprt/thread.h>
#include <iprt/err.h>
#include <iprt/assert.h>
#include <iprt/asm.h>

__BEGIN_DECLS
NTSTATUS NTAPI ZwYieldExecution(void);
__END_DECLS


RTDECL(RTNATIVETHREAD) RTThreadNativeSelf(void)
{
    return (RTNATIVETHREAD)PsGetCurrentThread();
}


RTDECL(int)   RTThreadSleep(unsigned cMillies)
{
    LARGE_INTEGER Interval;
    Interval.QuadPart = -(int64_t)cMillies * 10000;
    NTSTATUS rcNt = KeDelayExecutionThread(KernelMode, TRUE, &Interval);
    switch (rcNt)
    {
        case STATUS_SUCCESS:
            return VINF_SUCCESS;
        case STATUS_ALERTED:
        case STATUS_USER_APC:
            return VERR_INTERRUPTED;
        default:
            return RTErrConvertFromNtStatus(rcNt);
    }
}


RTDECL(bool) RTThreadYield(void)
{
    return ZwYieldExecution() != STATUS_NO_YIELD_PERFORMED;
}


RTDECL(bool) RTThreadPreemptIsEnabled(RTTHREAD hThread)
{
    Assert(hThread == NIL_RTTHREAD);
    KIRQL Irql = KeGetCurrentIrql();
    if (Irql > APC_LEVEL)
        return false;
#if defined(RT_ARCH_X86) || defined(RT_ARCH_AMD64)
    if (!(ASMGetFlags() & 0x00000200 /* X86_EFL_IF */))
        return false;
#endif
    return true;
}


RTDECL(void) RTThreadPreemptDisable(PRTTHREADPREEMPTSTATE pState)
{
    AssertPtr(pState);
    Assert(pState->uchOldIrql == 255);
    Assert(KeGetCurrentIrql() <= DISPATCH_LEVEL);

    KeRaiseIrql(DISPATCH_LEVEL, &pState->uchOldIrql);
}


RTDECL(void) RTThreadPreemptRestore(PRTTHREADPREEMPTSTATE pState)
{
    AssertPtr(pState);

    KeLowerIrql(pState->uchOldIrql);
    pState->uchOldIrql = 255;
}