INT 62 u - FGDRIVER v4.02 - "FG_VBADDR" - GET ADDRESS OF VIRTUAL BUFFER
	AX = 00CCh
	BX = virtual buffer handle (0000h-001Fh)
Return: DX:AX -> virtual buffer
Note:	the FGDRIVER functions are rearranged with each major release, but
	  their parameters do not change (see #03474)
SeeAlso: AX=00CDh,AX=00CEh,AX=00CFh,AX=00D3h