Format of VESA VBE CRTC Information Block:
Offset	Size	Description	)
 00h	WORD	total number of pixels horizontally
 02h	WORD	horizontal sync start (in pixels)
 04h	WORD	horizontal sync end (in pixels)
 06h	WORD	total number of scan lines
 08h	WORD	vertical sync start (in scan lines)
 0Ah	WORD	vertical sync end (in scan lines)
 0Ch	BYTE	flags (see #04084)
 0Dh	DWORD	pixel clock, in Hz
 11h	WORD	refresh rate, in 0.01 Hz units
		this field MUST be set to pixel_clock / (HTotal * VTotal),
		  even though it may not actually be used by the VBE
 13h 40 BYTEs	reserved