// Copyright (c) 1997-2009 Nokia Corporation and/or its subsidiary(-ies).
// All rights reserved.
// This component and the accompanying materials are made available
// under the terms of "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:
//

#include <setjmp.h>
#include <cpudefs.h>

extern "C" {

EXPORT_C __NAKED__ int setjmp(jmp_buf __jmpb)
	{
	asm ("mov eax, [esp+4]"); // eax = __jmpb
	asm ("mov [eax],    ebx");
	asm ("mov [eax+4],  esi");
	asm ("mov [eax+8],  edi");

	// Get caller's ESP by popping the parameter and the return address (8 bytes) from current ESP value
	asm ("mov edx, esp"); 
	asm ("add edx, 8"); 
	asm ("mov [eax+12], edx");	// caller's ESP
	asm ("mov [eax+16], ds");
	asm ("mov [eax+20], es");
	asm ("mov [eax+24], fs");
	asm ("mov [eax+28], gs");
	asm ("mov [eax+32], ebp");	// caller's EBP (stack frame)
	asm ("mov edx, [esp]");		// Save the retaddr because it's also the
	asm ("mov [eax+36], edx");	// place in the calling function to which longjmp() must return to
	asm ("mov eax, 0");
	asm ("ret");
	}

EXPORT_C __NAKED__ void longjmp(jmp_buf __jmpb, int __retval)
	{
	asm("mov eax, [esp+4]");	// eax = __jmpb

	// If __retval is 0 (KErrNone?) change it to a non-zero value
	asm("mov edx, [esp+8]");	// edx = __retval
	asm("cmp edx, 0");
	asm("jne is_not_zero");
	asm("inc edx"); 
	asm("is_not_zero:");	
	asm("mov [eax+40],edx");	// __jmpb[10]=__retval

	asm("mov ebp, [eax+12]");
	asm("mov esp, ebp");		// restore setjmp caller's ESP 
	asm("mov ebx, [eax]");
	asm("mov esi, [eax+4]");
	asm("mov edi, [eax+8]");
	asm("mov ds, [eax+16]");
	asm("mov es, [eax+20]");
	asm("mov fs, [eax+24]");
	asm("mov gs, [eax+28]");

	asm("mov ebp, [eax+32]"); // restore setjmp caller's EBP
		
	asm("mov eax, [eax+36]"); // push return address on stack
	asm("push eax");
	asm("mov eax,edx");	
	asm("ret");				// magically ret's to instruction following call to setjmp() with eax==__retval
	}

} // extern "C"