INT 10,F - Get Video State

	AH = 0F

	on return:
	AH = number of screen columns
	AL = mode currently set (see VIDEO MODES)
	BH = current display page

	- video modes greater than 13h on EGA, MCGA and VGA indicate
	  INT 10,0 was called with the high bit of the mode (AL) set
	  to 1, meaning the display does not need cleared
	- function returns byte value at 40:49;  On EGA, MCGA and
	  VGA bit 7 of register AL is determined by bit 7 of BIOS Data
	  Area byte 40:87.   This bit is usually set by INT 10,0
	  with bit 7 of the requested mode (in AL) set to 1