INT 10 - FRIEZE v7.41+ - INSTALLATION CHECK

	AH = 0Fh
	SI = F123h
	DI = 321Fh
Return: AH = number of character columns
	AL = display mode (see #00010 at AH=00h)
	BH = active page (see AH=05h)
	SI = DI = F345h if installed
Notes:	if mode was set with bit 7 set ("no blanking"), the returned mode will
	  also have bit 7 set
	EGA, VGA, and UltraVision return either AL=03h (color) or AL=07h
	  (monochrome) in all extended-row text modes
SeeAlso: AH=0Fh"VIDEO",AH=4Bh"FRIEZE"