Bitfields for Compaq advanced video functionality:
Bit(s)	Description	)
 31	future graphics extensions (reserved, set to 0)
 30-16	reserved
 15-12	available video memory in 256K blocks, less one (0000 = 256K, etc.)
 11-8	reserved
 7	QVision modes supported
 6	Advanced VGA modes supported
 5	Accelerated VGA modes supported
 4	standard VGA modes supported
 3-2	reserved
 1	132-column modes supported
 0	reserved