INT 78 - HugeRealMode Driver - INSTALLATION CHECK                               
	AX = 0000h
Return: AX = DBCAh if installed
Program: the HugeRealMode driver was published in the German DOS Extra Nr. 20
	  (1992), and makes a 4G flat address space (for both data and code)
	  available to real-mode DOS programs
SeeAlso: AX=0001h