INT 10 - VESA SuperVGA BIOS - CPU VIDEO MEMORY CONTROL

	AX = 4F05h
	BH = subfunction
	    00h select video memory window
		DX = window address in video memory (in granularity units)
	    01h get video memory window
		Return: DX = window address in video memory (in gran. units)
	BL = window number
	    00h window A
	    01h window B
	ES = selector for memory-mapped registers (VBE 2.0+, when called from
	      32-bit protected mode)
Return: AL = 4Fh if function supported
	AH = status
	    00h successful
	    01h failed
Note:	when using an accelerated video mode under VBE/AF v1.0P, the
	  application must call EnableDirectAccess before switching banks if
	  bit 9 of the video mode attributes flag is set (see #00080)
BUG:	Phoenix S3 Trio64V+ v1.02-02 reportedly returns garbage in DX for
	  subfunction 01h
SeeAlso: AX=4F01h,AX=4F06h,AX=4F07h,AX=7000h/BX=0004h