// Copyright (c) 2007-2009 Nokia Corporation and/or its subsidiary(-ies).

 // All rights reserved.

 // This component and the accompanying materials are made available

 // under the terms of the License "Eclipse Public License v1.0"

 // which accompanies this distribution, and is available

 // at the URL "http://www.eclipse.org/legal/epl-v10.html".

 //

 // Initial Contributors:

 // Nokia Corporation - initial contribution.

 //

 // Contributors:

 //

 // Description:

 // e32\nkernsmp\x86\ncsched.cia

 // 

 //

 #include <x86.h>

 #include <apic.h>

 // SubSchedulerLookupTable	: global data, type: TSubScheduler* [256];

 // BTraceLock				: global data, type: TSpinLock

 const TLinAddr TScheduler_Reschedule = (TLinAddr)&TScheduler::Reschedule;

 //const TLinAddr TheScheduler_iRescheduleNeededFlag = (TLinAddr)&TheScheduler.iRescheduleNeededFlag;

 const TLinAddr NKern_FastCounter = (TLinAddr)&NKern::FastCounter;

 const TLinAddr NKern_Lock = (TLinAddr)&NKern::Lock;

 const TLinAddr NKern_Unlock = (TLinAddr)&NKern::Unlock;

 const TLinAddr addressof_TheScheduler = (TLinAddr)&TheScheduler;

 const TUint32 new_thread_trace_header = ((8<<BTrace::ESizeIndex) + (BTrace::EContextIdPresent<<BTrace::EFlagsIndex*8) + (BTrace::ECpuUsage<<BTrace::ECategoryIndex*8) + (BTrace::ENewThreadContext<<BTrace::ESubCategoryIndex*8));

 extern "C" void __fastcall queue_dfcs(TSubScheduler* aS);

 extern "C" NThreadBase* __fastcall select_next_thread(TSubScheduler* aS);

 extern "C" void send_resched_ipis(TUint32 aMask);

 extern "C" void __fastcall do_forced_exit(NThreadBase* aT);

 extern "C" void NewThreadTrace(NThread* a);

 /***************************************************************************

 * Reschedule

 * Enter with:

 *		Kernel locked, interrupts enabled or disabled

 * Return with:

 *		Kernel unlocked, interrupts disabled

 *		EAX=0 if no reschedule occurred, 1 if it did

 *		ESI pointing to TSubScheduler for current CPU

 *		EDI pointing to current NThread

 ***************************************************************************/

 __NAKED__ void TScheduler::Reschedule()

 	{

 	asm("push 0 ");

 	asm("mov eax, ds:[%0]" : : "i" (X86_LOCAL_APIC_BASE + X86_LOCAL_APIC_OFFSET_ID));	// OK since kernel locked

 	asm("mov edi, %0" : : "i" (addressof_TheScheduler));

 	asm("shr eax, 24 ");

 	asm("mov esi, [eax*4+%0]" : : "i" (&SubSchedulerLookupTable));

 	asm("cli ");

 	asm("start_resched: ");

 //	_asm cmp dword ptr [esi]TSubScheduler.iRescheduleNeededFlag, 10000h		VC6 ignores the "dword ptr"

 	asm("lea eax, [esi+%0]" : : "i" _FOFF(TSubScheduler, iRescheduleNeededFlag));

 	asm("cmp dword ptr [eax], 0x10000 ");

 	asm("jb short resched_no_dfcs ");

 	asm("mov ecx, esi ");

 	asm("call %a0" : : "i" (&queue_dfcs));

 	asm("resched_no_dfcs: ");

 	asm("cmp byte ptr [esi+%0], 0" : : "i" _FOFF(TSubScheduler,iRescheduleNeededFlag));

 	asm("jz resched_not_needed ");

 	asm("sti ");

 	asm("mov dword ptr [esp], 1 ");

 	asm("mov ebp, [esi+%0]" : : "i"_FOFF(TSubScheduler, iCurrentThread));		// EBP -> original thread

 	asm("mov eax, cr0");

 	asm("push eax");

 	asm("mov [ebp+%0], esp" : : "i" _FOFF(NThreadBase, iSavedSP));			// Save original thread stack pointer

 	// We must move to a temporary stack before selecting the next thread.

 	// This is because another CPU may begin executing this thread before the

 	// select_next_thread() function returns and our stack would then be

 	// corrupted. We use the stack belonging to this CPU's initial thread since

 	// we are guaranteed that will never run on another CPU.

 	asm("mov ecx, [esi+%0]" : : "i" _FOFF(TSubScheduler, iInitialThread));

 	asm("mov esp, [ecx+%0]" : : "i" _FOFF(NThreadBase, iSavedSP));

 	asm("select_thread:");

 	asm("mov ecx, esi ");

 	asm("call %a0" : : "i" (&select_next_thread));

 	asm("mov ebx, eax ");

 	asm("cmp ebx, 0 ");

 	asm("jz no_thread ");

 	asm("mov esp, [ebx+%0]" : : "i" _FOFF(NThreadBase, iSavedSP)); // move to new thread's stack

 #ifdef BTRACE_CPU_USAGE

 	asm("cmp byte ptr %a0, 0" : : "i" (&BTraceData.iFilter[4]));

 	asm("jz short no_trace ");

 	asm("push ebx ");

 	asm("call %a0" : : "i" (NewThreadTrace));

 	asm("pop ebx ");

 	asm("no_trace: ");

 #endif	// BTRACE_CPU_USAGE

 	asm("cmp ebp, ebx ");

 	asm("je same_thread ");

 	asm("mov eax, [ebx+%0]" : : "i" _FOFF(NThreadBase, iStackBase));

 	asm("add eax, [ebx+%0]" : : "i" _FOFF(NThreadBase, iStackSize));

 	asm("mov ecx, [esi+60+%0]" : : "i" _FOFF(TSubScheduler, iExtras));		// iExtras[15] points to TSS

 	asm("mov [ecx+%0], eax" : : "i" _FOFF(TX86Tss, iEsp0));					// set ESP0 to top of new thread supervisor stack

 	asm("test byte ptr [ebx+%0], 2" : : "i" _FOFF(NThreadBase,i_ThrdAttr));	// test for address space switch

 	asm("jz short resched_no_as_switch ");

 	asm("call [edi+%0]" : : "i" _FOFF(TScheduler, iProcessHandler));		// call handler with

 														// EBX=pointer to new thread, EDI->scheduler, ESI->subscheduler

 	asm("resched_no_as_switch: ");

 	asm("same_thread: ");

 	asm("pop eax ");

 	asm("mov cr0, eax ");

 	asm("cli ");

 //	asm("cmp dword ptr [esi]TSubScheduler.iRescheduleNeededFlag, 0	VC6 ignores the "dword ptr"

 	asm("lea eax, [esi+%0]" : : "i" _FOFF(TSubScheduler, iRescheduleNeededFlag));

 	asm("cmp dword ptr [eax], 0 ");

 	asm("jnz start_resched ");

 	asm("resched_not_needed: ");

 	asm("mov edi, [esi+%0]" : : "i" _FOFF(TSubScheduler, iCurrentThread));

 	asm("cmp dword ptr [edi+%0], -3" : : "i" _FOFF(NThreadBase, iCsFunction)); // ECSDivertPending

 	asm("je resched_thread_divert ");

 	asm("mov dword ptr [esi+%0], 0" : : "i" _FOFF(TSubScheduler, iKernLockCount));

 	asm("pop eax ");

 	asm("ret ");

 	asm("resched_thread_divert: ");

 	asm("push edi ");

 	asm("xor eax, eax ");

 	asm("lock xchg eax, [esi+%0]" : : "i" _FOFF(TSubScheduler, iReschedIPIs));

 	asm("test eax, eax ");

 	asm("jz short no_resched_ipis ");

 	asm("push eax ");

 	asm("call %a0" : : "i" (&send_resched_ipis));

 	asm("add esp, 4 ");

 	asm("no_resched_ipis: ");

 	asm("sti ");

 	asm("mov ecx, [esp+12] ");			// SThreadReschedStack iReason 0 not run 1 unlock 2 IRQ

 	asm("cmp ecx, 2 ");

 	asm("ja short rtd_unknown ");		// unknown - die

 	asm("shl ecx, 2 ");					// reason * 4

 	asm("mov eax, 0xa1a ");

 	asm("shr eax, cl ");

 	asm("and eax, 15 ");

 	asm("mov gs, [esp+eax*4+16] ");		// restore GS

 	asm("pop ecx ");					// exiting thread pointer

 	asm("call %a0" : : "i" (&do_forced_exit));

 	asm("int 0xff ");					// should never get here

 	asm("rtd_unknown: ");

 	asm("int 0xff ");					// should never get here

 	// There is no thread ready to run

 	asm("no_thread: ");

 	asm("cli ");

 	asm("xor eax, eax ");

 	asm("lock xchg eax, [esi+%0]" : : "i" _FOFF(TSubScheduler, iReschedIPIs));

 	asm("test eax, eax ");

 	asm("jz short no_resched_ipis2 ");

 	asm("push eax ");

 	asm("call %a0" : : "i" (&send_resched_ipis));

 	asm("add esp, 4 ");

 	asm("no_resched_ipis2: ");

 	asm("sti ");

 	asm("hlt ");

 	asm("no_thread2: ");

 //	_asm cmp dword ptr [esi]TSubScheduler.iRescheduleNeededFlag, 10000h		VC6 ignores the "dword ptr"

 	asm("lea eax, [esi+%0]" : : "i" _FOFF(TSubScheduler, iRescheduleNeededFlag));

 	asm("cmp dword ptr [eax], 0x10000 ");

 	asm("jb short no_thread ");

 	asm("mov ecx, esi ");

 	asm("call %a0" : : "i" (&queue_dfcs));

 	asm("cmp byte ptr [esi+%0], 0" : : "i" _FOFF(TSubScheduler, iRescheduleNeededFlag));

 	asm("jz short no_thread2 ");

 	asm("jmp select_thread ");

 	}

 /** Disable interrupts to the specified level

 If aLevel = 0 does not affect interrupt state

 If aLevel <>0 disables all maskable interrupts.

 @param	aLevel level to which to disable

 @return	Cookie to pass into RestoreInterrupts()

 */

 EXPORT_C __NAKED__ TInt NKern::DisableInterrupts(TInt /*aLevel*/)

 	{

 	asm("pushfd");

 	asm("mov ecx, [esp+4]");

 	asm("pop eax");

 	asm("and eax, 0x200");

 	asm("test ecx, ecx");

 	asm("jz disable_ints_0");

 	asm("cli");

 	asm("disable_ints_0:");

 	asm("ret");

 	}

 /** Disable all maskable interrupts

 @return	Cookie to pass into RestoreInterrupts()

 */

 EXPORT_C __NAKED__ TInt NKern::DisableAllInterrupts()

 	{

 	asm("pushfd");

 	asm("pop eax");

 	asm("and eax, 0x200");

 	asm("cli");

 	asm("ret");

 	}

 /** Restore interrupt mask to state preceding a DisableInterrupts() call

 @param	aLevel Cookie returned by Disable(All)Interrupts()

 */

 EXPORT_C __NAKED__ void NKern::RestoreInterrupts(TInt aLevel)

 	{

 	asm("test byte ptr [esp+5], 2");	// test saved I flag

 	asm("jz restore_irq_off");			// jump if clear

 	asm("sti");							// else reenable interrupts

 	asm("ret");

 	asm("restore_irq_off:");

 	asm("cli");

 	asm("ret");

 	}

 /** Enable all maskable interrupts

 @internalComponent

 */

 EXPORT_C __NAKED__ void NKern::EnableAllInterrupts()

 	{

 	asm("sti");

 	asm("ret");

 	}

 /**	Unlocks the kernel

 	Decrements iKernCSLocked; if it becomes zero and IDFCs or a reschedule are

 	pending, calls the scheduler to process them.

 	@pre	Thread or IDFC context. Don't call from ISRs.

  */

 EXPORT_C __NAKED__ void NKern::Unlock()

 	{

 	asm("mov eax, ds:[%0]" : : "i" (X86_LOCAL_APIC_BASE + X86_LOCAL_APIC_OFFSET_ID)); // OK since kernel locked

 	asm("shr eax, 24 ");

 	asm("push esi ");

 	asm("mov esi, [eax*4+%0]" : : "i" (&SubSchedulerLookupTable));

 #ifdef _DEBUG

 	asm("cmp dword ptr [esi+%0], 0" : : "i" _FOFF(TSubScheduler, iKernLockCount));

 	asm("jg short _dbg1 ");

 	asm("int 0xff ");

 	asm("_dbg1: ");

 #endif

 	asm("cli ");

 	asm("dec dword ptr [esi+%0]" : : "i" _FOFF(TSubScheduler, iKernLockCount));

 	asm("jnz short still_locked ");

 //	asm("cmp dword ptr [esi]TSubScheduler.iRescheduleNeededFlag, 0	VC6 ignores the "dword ptr"

 	asm("lea eax, [esi+%0]" : : "i" _FOFF(TSubScheduler, iRescheduleNeededFlag));

 	asm("cmp dword ptr [eax], 0 ");

 	asm("jz short no_resched ");

 	asm("mov dword ptr [esi+%0], 1" : : "i" _FOFF(TSubScheduler, iKernLockCount));

 	asm("push edi ");

 	asm("push ebp ");

 	asm("push ebx ");

 	asm("push gs ");

 	asm("push fs ");

 	asm("sti ");

 	// Reschedule - return with local interrupts disabled, iKernLockCount=0

 	asm("push 1 ");

 	asm("call %a0" : : "i" (TScheduler_Reschedule));

 	asm("add esp, 4 ");

 	asm("xor eax, eax ");

 	asm("lock xchg eax, [esi+%0]" : : "i" _FOFF(TSubScheduler, iReschedIPIs));

 	asm("test eax, eax ");

 	asm("jz short no_resched_ipis_ul ");

 	asm("unlock_do_resched_ipis: ");

 	asm("push eax ");

 	asm("call %a0" : : "i" (&send_resched_ipis));

 	asm("add esp, 4 ");

 	asm("no_resched_ipis_ul: ");

 	asm("pop fs ");

 	asm("pop gs ");

 	asm("pop ebx ");

 	asm("pop ebp ");

 	asm("pop edi ");

 	asm("still_locked: ");

 	asm("sti ");

 	asm("pop esi ");

 	asm("ret ");

 	asm("no_resched: ");

 	asm("xor eax, eax ");

 	asm("lock xchg eax, [esi+%0]" : : "i" _FOFF(TSubScheduler, iReschedIPIs));

 	asm("test eax, eax ");

 	asm("jz short still_locked ");

 	asm("push edi ");

 	asm("push ebp ");

 	asm("push ebx ");

 	asm("push gs ");

 	asm("push fs ");

 	asm("jmp short unlock_do_resched_ipis ");

 	}

 /**	Locks the kernel

 	Defer IDFCs and preemption

 	@pre	Thread or IDFC context. Don't call from ISRs.

  */

 EXPORT_C __NAKED__ void NKern::Lock()

 	{

 	asm("cli");		// stop thread migration between reading APIC ID and subscheduler stuff

 	asm("mov eax, ds:[%0]" : : "i"(X86_LOCAL_APIC_BASE + X86_LOCAL_APIC_OFFSET_ID));

 	asm("shr eax, 24");

 	asm("mov ecx, [eax*4+%0]" : : "i"(&SubSchedulerLookupTable));

 	asm("inc dword ptr [ecx+%0]": : "i"_FOFF(TSubScheduler, iKernLockCount));

 	asm("sti");

 	asm("ret");

 	}

 /**	Locks the kernel and returns a pointer to the current thread

 	Defer IDFCs and preemption

 	@pre	Thread or IDFC context. Don't call from ISRs.

  */

 EXPORT_C __NAKED__ NThread* NKern::LockC()

 	{

 	asm("cli");		// stop thread migration between reading APIC ID and subscheduler stuff

 	asm("mov eax, ds:[%0]" : : "i"(X86_LOCAL_APIC_BASE + X86_LOCAL_APIC_OFFSET_ID));

 	asm("shr eax, 24");

 	asm("mov ecx, [eax*4+%0]" : : "i"(&SubSchedulerLookupTable));

 	asm("inc dword ptr [ecx+%0]": : "i"_FOFF(TSubScheduler, iKernLockCount));

 	asm("mov eax, [ecx+%0]" : : "i"_FOFF(TSubScheduler, iCurrentThread));

 	asm("sti");

 	asm("ret");

 	}

 /**	Allows IDFCs and rescheduling if they are pending.

 	If IDFCs or a reschedule are pending and iKernCSLocked is exactly equal to 1

 	calls the scheduler to process the IDFCs and possibly reschedule.

 	@return	Nonzero if a reschedule actually occurred, zero if not.

 	@pre	Thread or IDFC context. Don't call from ISRs.

  */

 EXPORT_C __NAKED__ TInt NKern::PreemptionPoint()

 	{

 	asm("mov eax, ds:[%0]" : : "i"(X86_LOCAL_APIC_BASE + X86_LOCAL_APIC_OFFSET_ID));

 	asm("shr eax, 24");

 	asm("mov ecx, [eax*4+%0]" : : "i"(&SubSchedulerLookupTable));

 #ifdef _DEBUG

 	asm("cmp dword ptr [ecx+%0], 0": : "i"_FOFF(TSubScheduler, iKernLockCount));

 	asm("jg _dbg1_pp");

 	asm("int 0xff");

 	asm("_dbg1_pp:");

 #endif

 	asm("cmp dword ptr [ecx+%0], 1": : "i"_FOFF(TSubScheduler, iKernLockCount));

 	asm("jnz still_locked_pp");

 //	asm("cmp dword ptr [ecx]TSubScheduler.iRescheduleNeededFlag, 0		VC6 ignores the "dword ptr"

 	asm("lea eax, [ecx+%0]": : "i"_FOFF(TSubScheduler, iRescheduleNeededFlag));

 	asm("cmp dword ptr [eax], 0");

 	asm("jnz do_resched");

 	asm("cli");

 	asm("lock xchg eax, [ecx+%0]": : "i"_FOFF(TSubScheduler, iReschedIPIs));

 	asm("test eax, eax");

 	asm("jz pp_no_resched_ipis");

 	asm("push eax");

 	asm("call %a0": :"i"(&send_resched_ipis));

 	asm("add esp, 4");

 	asm("pp_no_resched_ipis:");

 	asm("sti");

 	asm("still_locked_pp:");

 	asm("xor eax, eax");

 	asm("ret");

 	asm("do_resched:");

 	asm("call %a0" : : "i"(NKern_Unlock));

 	asm("call %a0" : : "i"(NKern_Lock));

 	asm("mov eax, 1");

 	asm("ret");

 	}

 /** Complete the saving of a thread's context

 This saves the FPU registers if necessary once we know that we are definitely

 switching threads.

 @internalComponent

 */

 __NAKED__ void NThread::CompleteContextSave()

 	{

 	THISCALL_PROLOG0()

 	asm("mov edx, [ecx+%0]": : "i"_FOFF(NThreadBase,iSavedSP));	// EDX points to saved state on thread stack

 	asm("test byte ptr [edx], 8");						// test thread's saved TS flag

 	asm("jnz no_fpu");									// if set, thread did not use FPU

 	asm("clts");

 	asm("fnsave [ecx+%0]": : "i"_FOFF(NThread, iCoprocessorState));	// else thread did use FPU - save its state

 	asm("or byte ptr [edx], 8");						// set TS flag so thread aborts next time it uses FPU

 	asm("fwait");

 	asm("no_fpu:");

 	THISCALL_EPILOG0()

 	}

 /** Check if the kernel is locked the specified number of times.

 	@param aCount	The number of times the kernel should be locked

 					If zero, tests if it is locked at all

 	@return TRUE if the tested condition is true.

 	@internalTechnology

 */

 EXPORT_C __NAKED__ TBool NKern::KernelLocked(TInt /*aCount*/)

 	{

 	asm("pushfd");

 	asm("cli");

 	asm("mov eax, ds:[%0]" : : "i"(X86_LOCAL_APIC_BASE + X86_LOCAL_APIC_OFFSET_ID));

 	asm("shr eax, 24");

 	asm("mov eax, [eax*4+%0]" : : "i"(&SubSchedulerLookupTable));

 	asm("mov edx, [eax+%0]": : "i"_FOFF(TSubScheduler, iKernLockCount));

 	asm("popfd");

 	asm("cmp edx, 0");

 	asm("jz not_locked");

 	asm("mov eax, [esp+4]");

 	asm("cmp eax, 0");

 	asm("jz locked");

 	asm("cmp eax, edx");

 	asm("jnz not_locked");

 	asm("locked:");

 	asm("mov eax, 1");

 	asm("ret");

 	asm("not_locked:");

 	asm("xor eax, eax");

 	asm("ret");

 	}

 // Only call this if thread migration is disabled, i.e.

 // interrupts disabled, kernel locked or current thread in 'freeze cpu' mode

 extern "C" __NAKED__ TSubScheduler& SubScheduler()

 	{

 	asm("mov eax, ds:[%0]" : : "i"(X86_LOCAL_APIC_BASE + X86_LOCAL_APIC_OFFSET_ID));

 	asm("shr eax, 24");

 	asm("mov eax, [eax*4+%0]" : : "i"(&SubSchedulerLookupTable));

 	asm("ret");

 	}

 /** Returns the NThread control block for the currently scheduled thread.

     Note that this is the calling thread if called from a thread context, or the

 	interrupted thread if called from an interrupt context.

 	@return A pointer to the NThread for the currently scheduled thread.

 	@pre Call in any context.

 */

 EXPORT_C __NAKED__ NThread* NKern::CurrentThread()

 	{

 	asm("pushfd");

 	asm("cli");		// stop thread migration between reading APIC ID and thread pointer

 	asm("mov eax, ds:[%0]" : : "i"(X86_LOCAL_APIC_BASE + X86_LOCAL_APIC_OFFSET_ID));

 	asm("shr eax, 24");

 	asm("mov eax, [eax*4+%0]" : : "i"(&SubSchedulerLookupTable));

 	asm("cmp eax, 0");

 	asm("jz done");

 	asm("test al, 3");

 	asm("jnz bad_ct");

 	asm("mov eax, [eax+%0]": : "i"_FOFF(TSubScheduler, iCurrentThread));

 	asm("done:");

 	asm("popfd");

 	asm("ret");

 	asm("bad_ct:");

 	asm("popfd");

 	asm("xor eax, eax");

 	asm("ret");

 	}

 /** Returns the NThread control block for the currently scheduled thread.

     Note that this is the calling thread if called from a thread context, or the

 	interrupted thread if called from an interrupt context.

 	@return A pointer to the NThread for the currently scheduled thread.

 	@pre Call with migration disabled - i.e. from an ISR, IDFC, with interrupts

 			disabled or with preemption disabled.

 */

 extern "C" __NAKED__ NThread* NCurrentThreadL()

 	{

 	asm("mov eax, ds:[%0]" : : "i"(X86_LOCAL_APIC_BASE + X86_LOCAL_APIC_OFFSET_ID));

 	asm("shr eax, 24");

 	asm("mov eax, [eax*4+%0]" : : "i"(&SubSchedulerLookupTable));

 	asm("mov eax, [eax+%0]": : "i"_FOFF(TSubScheduler, iCurrentThread));

 	asm("ret");

 	}

 /** Returns the CPU number of the calling CPU.

 	@return the CPU number of the calling CPU.

 	@pre Call in any context.

 */

 EXPORT_C __NAKED__ TInt NKern::CurrentCpu()

 	{

 	asm("xor eax, eax");

 	asm("str ax");

 	asm("sub al, 0x28");

 	asm("shr al, 3");

 	asm("ret");

 	}

 /**	Return the current processor context type (thread, IDFC or interrupt)

 	@return	A value from NKern::TContext enumeration (but never EEscaped)

 	@pre	Any context

 	@see	NKern::TContext

  */

 EXPORT_C __NAKED__ TInt NKern::CurrentContext()

 	{

 	asm("pushfd");

 	asm("cli");		// stop thread migration between reading APIC ID and subscheduler stuff

 	asm("mov edx, ds:[%0]": :"i"(X86_LOCAL_APIC_BASE + X86_LOCAL_APIC_OFFSET_ID));

 	asm("xor eax, eax");

 	asm("shr edx, 24");

 	asm("mov edx, [edx*4+%0]" : : "i"(&SubSchedulerLookupTable));

 	asm("cmp edx, eax");

 	asm("jz bad_cc");

 	asm("test dl, 3");

 	asm("jnz bad_cc");

 	asm("cmp eax, [edx+52+%0]": : "i"_FOFF(TSubScheduler,iExtras)); // i_IrqNestCount

 	asm("jle irq");

 	asm("cmp al, [edx+%0]": : "i"_FOFF(TSubScheduler, iInIDFC));

 	asm("jz thread");

 	asm("jmp idfc");

 	asm("bad_cc:");			// no subscheduler yet [initialising] - return EInterrupt

 	asm("irq:");			// return NKern::EInterrupt [=2]

 	asm("inc eax");

 	asm("idfc:");			// return NKern::EIDFC [=1]

 	asm("inc eax");

 	asm("thread:");			// return NKern::EThread [=0]

 	asm("popfd");

 	asm("ret");

 	}

 #ifdef __USE_LOGICAL_DEST_MODE__

 extern "C" __NAKED__ void __fastcall do_send_resched_ipis(TUint32)

 	{

 	asm("shl ecx, 24 ");		// CPUs mask into bits 24-31

 	asm("jz short sri0 ");		// no CPUs, so nothing to do

 	asm("pushfd ");

 	asm("cli ");

 	asm("mov ds:[%0], ecx" : : "i" (X86_LOCAL_APIC_BASE + X86_LOCAL_APIC_OFFSET_ICRH));

 	asm("mov eax, %0" : : "i" (RESCHED_IPI_VECTOR | 0x4800));

 	asm("mov ds:[%0], eax" : : "i" (X86_LOCAL_APIC_BASE + X86_LOCAL_APIC_OFFSET_ICRL));

 	asm("popfd ");

 	asm("sri0: ");

 	asm("ret ");

 	}

 #endif

 extern "C" __NAKED__ void __fastcall send_ipi(TUint32)

 	{

 	asm("pushfd ");

 	asm("cli ");

 	asm("mov ds:[%0], ecx" : : "i" (X86_LOCAL_APIC_BASE + X86_LOCAL_APIC_OFFSET_ICRH));

 	asm("mov eax, %0" : : "i" (RESCHED_IPI_VECTOR | 0x4000));

 	asm("mov ds:[%0], eax" : : "i" (X86_LOCAL_APIC_BASE + X86_LOCAL_APIC_OFFSET_ICRL));

 	asm("popfd ");

 	asm("ret ");

 	}

 // Send a reschedule IPI to the current processor

 // *** DON'T DO ANY TRACING OR INSTRUMENTATION ***

 extern "C" __NAKED__ void send_self_resched_ipi()

 	{

 	asm("pushfd ");

 	asm("cli ");

 	asm("xor ecx, ecx ");

 	asm("mov ds:[%0], ecx" : : "i" (X86_LOCAL_APIC_BASE + X86_LOCAL_APIC_OFFSET_ICRH));

 	asm("mov eax, %0" : : "i" (RESCHED_IPI_VECTOR | 0x44000));	// destination shorthand = self

 	asm("mov ds:[%0], eax" : : "i" (X86_LOCAL_APIC_BASE + X86_LOCAL_APIC_OFFSET_ICRL));

 	asm("popfd ");

 	asm("ret ");

 	}

 extern "C" __NAKED__ void send_irq_ipi(TSubScheduler*)

 	{

 	asm("mov ecx, [esp+4] ");

 	asm("pushfd ");

 	asm("mov edx, [ecx+%0]" : : "i" _FOFF(TSubScheduler, i_APICID));

 	asm("cli ");

 	asm("mov ds:[%0], edx" : : "i" (X86_LOCAL_APIC_BASE + X86_LOCAL_APIC_OFFSET_ICRH));

 	asm("mov eax, %0" : : "i" (TRANSFERRED_IRQ_VECTOR | 0x4000));

 	asm("mov ds:[%0], eax" : : "i" (X86_LOCAL_APIC_BASE + X86_LOCAL_APIC_OFFSET_ICRL));

 	asm("popfd ");

 	asm("ret ");

 	}