LPVOID VirtualInit (DWORD virtualPages, DWORD physicalPages)
{
	/* Check for straight out wrong cases. */
	if (virtualPages < physicalPages)
	{
		print_error("Fewer virtual pages than physical pages");
		return NULL;
	}
	if (virtualPages > MAX_VIRTUAL_PAGES)
	{
		print_error("Too many virtual pages");
		return NULL;
	}
	if (physicalPages > MAX_PHYSICAL_PAGES)
	{
		print_error("Too many physical pages");
		return NULL;
	}

	/* First initialize global variables. */
	crt_frame = -1;
	memory = NULL;
	physicalMemory = NULL;
	virtualMemory = NULL;
	memoryPages = physicalPages;
	swapPages = virtualPages;

	/* Try to set up files for use with memory.*/
	hndRam = CreateFile(RAM_FILE,
		GENERIC_READ | GENERIC_WRITE,
		FILE_SHARE_READ | FILE_SHARE_WRITE,
		NULL,
		CREATE_ALWAYS,
		FILE_ATTRIBUTE_NORMAL,
		NULL);
	if (hndRam == INVALID_HANDLE_VALUE)
	{
		error_message(__FILE__, __LINE__);
		return NULL;
	}

	hndSwap = CreateFile(SWAP_FILE,
		GENERIC_READ | GENERIC_WRITE,
		FILE_SHARE_READ | FILE_SHARE_WRITE,
		NULL,
		CREATE_ALWAYS,
		FILE_ATTRIBUTE_NORMAL,
		0);
	if (hndSwap == INVALID_HANDLE_VALUE)
	{
		error_message(__FILE__, __LINE__);
		return NULL;
	}

	/*allocate memory in process space*/
	memory = VirtualAlloc(memory,
		virtualPages * pageSize,
		MEM_COMMIT,
		PAGE_NOACCESS);

	if (memory == NULL)
	{
		error_message(__FILE__, __LINE__);
		return NULL;
	}

	/* Create file mappings. */
	hndRamMapping = CreateFileMapping(hndRam,
		NULL,
		PAGE_READWRITE,
		0,
		physicalPages * pageSize,
		NULL);
	if (hndRamMapping == NULL)
	{
		error_message(__FILE__, __LINE__);
		return NULL;
	}

	hndSwapMapping = CreateFileMapping(hndSwap,
		NULL,
		PAGE_READWRITE,
		0,
		virtualPages * pageSize,
		NULL);
	if (hndSwapMapping == NULL)
	{
		error_message(__FILE__, __LINE__);
		return NULL;
	}

	/* map physical memory */
	physicalMemory = (char*)MapViewOfFile(hndRamMapping,
		FILE_MAP_WRITE,
		0,
		0,
		0);

	printf("\nPhysical memory at: 0x%x (NULL at: 0x%x)\n", physicalMemory, NULL);

	if (physicalMemory == NULL)
	{
		error_message(__FILE__, __LINE__);
		return NULL;
	}

	/* map virtual memory. */
	virtualMemory = (char*)MapViewOfFile(hndSwapMapping,
		FILE_MAP_WRITE,
		0,
		0,
		0);
	if (virtualMemory == NULL)
	{
		error_message(__FILE__, __LINE__);
		return NULL;
	}


	/*set interrupt handler*/
	handler = AddVectoredExceptionHandler(1, PageFaultVectoredHandler);
	if (handler == NULL)
	{
		error_message(__FILE__, __LINE__);
		return NULL;
	}

	/* initialize data structures */
	init_mem_pages(pages, MAX_PHYSICAL_PAGES);
	init_mem_frames(frames, MAX_VIRTUAL_PAGES);

	return memory;
}