INT 62 u - FGDRIVER v4.02 - "FG_GETLINES" - GET TEXT ROWS FOR CURR VIDEO MODE
	AX = 0047h
Return: AX = number of text rows on screen in current video mode
Note:	the FGDRIVER functions are rearranged with each major release, but
	  their parameters do not change (see #03474 at AX=0000h)
SeeAlso: AX=00AFh,AX=00C2h