Constants

      LMem_CRTPortBase = $463
      LMem_BufferLength= $44c
      LMem_NumberOfRows= $484
      LMem_NumberOfCols= $44a
      LMem_CurrentMode = $449
      LMem_BIOSFlags   = $489

    These are for internal use.   They  refer to low memory addresses for
    video card information.

      MonoCard         =    1
      ColorCard        =    2

    These are used to determine which monitor the unit should display to.

      Blink            =  128
      Black            =    0
      Blue             =    1
      Green            =    2
      Cyan             =    3
      Red              =    4
      Magenta          =    5
      Brown            =    6
      LightGray        =    7
      LightGrey        =    7
      DarkGray         =    8
      DarkGrey         =    8
      LightBlue        =    9
      LightGreen       =   10
      LightCyan        =   11
      LightRed         =   12
      LightMagenta     =   13
      Yellow           =   14
      White            =   15

    These simply replace the CRT constants.