INT 10 - VESA SuperVGA BIOS - GET VBE/AF v1.0P DEVICE CONTEXT BUFFER

	AX = 4F0Bh
	BL = subfunction
	    00h get length of device context buffer
	    01h initialize device context buffer
		ES:DI -> real-mode address of buffer (see #00089)
Return: AL = 4Fh if function supported
	AH = status
	    00h successful
		CX = number of bytes required for buffer (if BL=00h on entry)
		ES:DI buffer initialized (if BL=01h on entry)
	    01h failed
Note:	this interface description is derived from the draft VBE/AF proposal
	  (version 1.0P, document revsion 0.12P, dated 13jan95)
SeeAlso: AX=4F00h,AX=4F01h,AX=4F17h