os/kernelhwsrv/kernel/eka/euser/epoc/win32/uc_trp.cpp
author sl@SLION-WIN7.fritz.box
Fri, 15 Jun 2012 03:10:57 +0200
changeset 0 bde4ae8d615e
permissions -rw-r--r--
First public contribution.
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// Copyright (c) 1995-2009 Nokia Corporation and/or its subsidiary(-ies).
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// All rights reserved.
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// This component and the accompanying materials are made available
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// under the terms of the License "Eclipse Public License v1.0"
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// which accompanies this distribution, and is available
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// at the URL "http://www.eclipse.org/legal/epl-v10.html".
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//
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// Initial Contributors:
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// Nokia Corporation - initial contribution.
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//
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// Contributors:
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//
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// Description:
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// e32\euser\epoc\win32\uc_trp.cpp
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// 
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//
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#include <u32exec.h>
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#include <e32panic.h>
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#include "uc_std.h"
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GLREF_C void Panic(TCdtPanic);
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#ifndef __LEAVE_EQUALS_THROW__
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// __thiscall - parameter is expected to be removed by this function
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EXPORT_C TInt TTrap::Trap(TInt &aResult)
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//
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// Save the enter frame state and return 0.
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//
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	{
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	// compiler generates push ebp; mov ebp,esp here
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	// hence correct action for Leave() is to restore ebp then mov esp,ebp; pop ebp; ret 4
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	aResult=KErrNone;
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	iResult=(&aResult);
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	_asm mov eax, this
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	_asm mov [eax], ebx
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	_asm mov [eax+4], esi
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	_asm mov [eax+8], edi
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	_asm mov [eax+12], ebp
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	_asm mov [eax+16], ds
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	_asm mov [eax+20], es
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	_asm mov [eax+24], fs
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	_asm mov [eax+28], gs
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	_asm mov edx, [ebp]
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	_asm mov [eax+32], edx
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	_asm mov edx, [ebp+4]
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	_asm mov [eax+36], edx
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	TTrapHandler* h = Exec::PushTrapFrame(this);
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	if (h != NULL)
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		h->Trap();
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	return(0);
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	}
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// __cdecl - this function will leave parameter on the stack
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// but it will return to the instruction after the call to TTrap::Trap()
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// and this expects a parameter to be popped from the stack
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// so we must return with a ret 4, rather than leaving the compiler to generate a ret 0
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EXPORT_C void User::Leave(TInt aReason)
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/**
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Leaves the currently executing function, unwinds the call stack, and returns
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from the most recently entered trap harness.
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@param aReason The value returned from the most recent call to TRAP or TRAPD.
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               This is known as the reason code and, typically, it gives the
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               reason for the environment or user error causing this leave
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               to occur.
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@see TRAP
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@see TRAPD              
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*/
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	{
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	TTrap *pT=Exec::PopTrapFrame();
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    if (!pT)
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        ::Panic(EUserLeaveWithoutTrap);
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	TTrapHandler *pH=pT->iHandler;
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	*pT->iResult=aReason;
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	if (pH!=NULL)
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		pH->Leave(aReason);
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	_asm mov eax, pT
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	_asm mov ebp, [eax+12]
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	_asm mov esp, ebp
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	_asm mov ebx, [eax]
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	_asm mov esi, [eax+4]
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	_asm mov edi, [eax+8]
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	_asm mov ds, [eax+16]
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	_asm mov es, [eax+20]
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	_asm mov fs, [eax+24]
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	_asm mov gs, [eax+28]
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	_asm mov edx, [eax+32]
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	_asm mov [ebp], edx
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	_asm mov edx, [eax+36]
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	_asm mov [ebp+4], edx
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	_asm mov eax, 1
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	_asm pop ebp
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	_asm ret 4
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	}
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#endif // !__LEAVE_EQUALS_THROW__