Int 10h, 12h /BL=10h    Return Video Configuration                   EGA, VGA

    Returns video configuration information.

        Entry   AH = 12h
                BL = 10h

        Return  BH = Display mode in effect
                    | 00h   Color mode (03Dxh port addresses)
                    | 01h   Monochrome mode (03Bxh port addresses)
                BL = Amount of video RAM
                    | 00h   64K
                    | 01h   128K
                    | 02h   192K
                    | 03h   256K
                CH = Adapter (feature) bits  (valid on EGA only)
                CL = Switch setting

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    The value returned in CL (Switch setting) represents the DIP
    switch settings on the EGA. The Adapter bits (CH) is defined as
    follows:

                        Adapter bits (CH)

                        7 6 5 4 3 2 1 0
                        x x x x . . . .       Unused
                        . . . . x x . .       Reserved
                        . . . . . . x .       FEAT1 (pin 17)
                        . . . . . . . x       FEAT0 (pin 19)