2115  wb++?- VMAINC - Video Port Control

        "Video Memory Address Increment"

        i---mmjj

        i    = Address increment mode:
                0 => increment after writing $2118/reading $2139
                1 => increment after writing $2119/reading $213a
            Note that a word write stores low first, then high. Thus, if you're
            storing a word value to $2118/9, you'll probably want to set 1
            here.

        j    = Address increment amount
            00 = Normal increment by 1

            01 = Increment by 32

                 Useful for reading / writing a normal tilemap
                 when one would like to have the target address
                 move to the next row upon increment.

            10 = Increment by 128

                 Useful for reading / writing a mode 7 tilemap
                 when one would like to have the target address
                 move to the next row upon increment.

            11 = Increment by 128

                 (Note: Same as address increment amount '10' above)

        m    = Address remapping
            00 = No remapping

            # 0x00, 0x01, 0x02, 0x03, ..., 0x1F => 0x00, 0x08, 0x10, 0x18, ..., 0xF8
            # 0x20, 0x21, 0x22, 0x23, ..., 0x3F => 0x01, 0x09, 0x11, 0x19, ..., 0xF9
            01 = Remap addressing aaaaaaaa BBBccccc => aaaaaaaa cccccBBB

            # 0x00, 0x01, 0x02, 0x03, ..., 0x3F => 0x00, 0x08, 0x10, 0x18, ..., 0x1F8
            # 0x40, 0x41, 0x42, 0x43, ..., 0x7F => 0x01, 0x09, 0x11, 0x19, ..., 0x1F9
            10 = Remap addressing aaaaaaaB BBcccccc => aaaaaaac cccccBBB

            # 0x00, 0x01, 0x02, 0x03, ..., 0x7F => 0x00, 0x08, 0x10, 0x18, ..., 0x3F8
            # 0x80, 0x81, 0x82, 0x83, ..., 0xFF => 0x00, 0x09, 0x11, 0x19, ..., 0x3F9
            11 = Remap addressing aaaaaaBB Bccccccc => aaaaaacc cccccBBB

            The "remap" modes basically implement address translation. If
            $2116/7 are set to #$0003, then word address #$0018 will be written
            instead, and $2116/7 will be incremented to $0004.