INT 10,FF - Update DESQView/TopView Virtual Screen Regen Buffer

	AH = FF
	CX = number of characters changed
	ES:DI = pointer to first character in buffer to change,  ES is
		set to segment returned by INT 10,FE

	returns nothing

	- the physical screen does not get updated until INT 10,FF is
	  called in TopView
	- it is not necessary to make this call under DESQView since it
	  handles updates automatically
	- calling this function under DESQView will cancel the automatic
	  update mode