INT 49 - TI Professional PCIBM PC - CRT - SET PROTECTED STATUS AREA
	AH = 15h
	CL = row at which to start status area, or 00h to cancel
	CH = 00h
Return: nothing
Desc:	set a protected area of the screen which will not be affected by TTY
	  writes or the scrolls they may generate
Notes:	AH=00h,04h,05h,0Bh,0Ch,0Dh,0Fh are documented as NOPs
	the current cursor position must be above the status area in order to
	  set the protected area
SeeAlso: AH=01h,AH=02h