Format of HyperPAD data area:
Offset	Size	Description	)
 -16h	DWORD	pointer to ??? FAR function
 -12h	DWORD	pointer to callback setting function
		[C calling conventions, (*callback)(int (_loadds far *)()) ]
 -0Eh 6 BYTEs	signature "BRC001"
 -08h	DWORD	pointer to previous INT 7D handler
 -04h	DWORD	pointer to ??? data
 00h		HyperPAD INT 7D handler