INT 62 u - FGDRIVER v4.02 - "FG_VBHANDLE" - GET ACTIVE VIRTUAL BUFFER'S HANDLE
	AX = 00D3h
Return: AX = handle for active virtual buffer
Note:	the FGDRIVER functions are rearranged with each major release, but
	  their parameters do not change (see #03474)
SeeAlso: AX=00CCh,AX=00D4h