INT 10,3 - Read Cursor Position and Size

	AH = 03
	BH = video page

	on return:
	CH = cursor starting scan line (low order 5 bits)
	CL = cursor ending scan line (low order 5 bits)
	DH = row
	DL = column

	- returns data from BIOS DATA AREA locations 40:50, 40:60 and 40:61
	- the 6845 can also be used to read the cursor position
	- the return data can be circumvented by direct port I/O to the 6845
	  CRT Controller since this function returns the data found in the
	  BIOS Data Area without actually checking the controller