HiRes                    Sets Screen to High-Resolution Mode

 HiRes;                                                                  [TP]

    Sets the display to a 640x200 "black-and-white" display, clearing the
    screen as it does so.

          Notes:    X coordinates (columns) range from 0..639; Y
                    coordinates (rows) range from 0..199. To get back to a
                    regular text display, call Textmode.

                    Text can also be displayed in this mode, allowing 80 x
                    25 characters.

                    This display mode uses a black background, while
                    allowing the pixel dots to have one of 16 colors by
                    using HiResColor.

                    This procedure also resets the graphics window to
                    (0,0),(639,199), destroying any previous graphics
                    window setting.

  -------------------------------- Example ---------------------------------

           HiRes;                   { set to 640x200 monochrome mode }