Bitfields for VESA/VBE video mode number:
Bit(s)	Description	)
 15	preserve display memory on mode change
 14	(VBE v2.0+) use linear (flat) frame buffer
 13	(VBE/AF 1.0P) VBE/AF initializes accelerator hardware
 12	reserved for VBE/AF
 11	(VBE v3.0) user user-specified CRTC refresh rate values
 10-9	reserved for future expansion
 8-0	video mode number (0xxh are non-VESA modes, 1xxh are VESA-defined)