Draft4 being ported to Pitrex (Vectrex)

Описание: This is Ken Chisholm's "Draft4" program from around 1975, being ported to the Vectrex (1982). It does run on the Vectrex in native 6809 code but this particular version is actually running on a Raspberry Pi Zero in a PiTrex cartridge - mainly because it's a better development environment but also because it flickers less at the start of the game when more vectors are being drawn. The native Vectrex version will probably forgo the board background, and use an overlay instead to draw the checkerboard. The code in the video is not quite finished; I'm still working on the error messages and the picking up and moving of pieces.
(There is some debugging information at the bottom of the display. The number on the right is the computer's evaluation of the strength of its position versus that of the human opponent)