FORTH for the PC-G850(V)(S)

[robve]

Forth850 is now available: https://github.com/Robert-van-Engelen/Forth850

It has 294 words in an 8K executable, including 2xx and Dxx words for double cells, 256 byte string buffers PAD, TIB and TMP, string operations, exceptions THROW and CATCH, VALUE, 2VALUE, FORGET, VOCABULARY, simple graphics with DRAW and VIEW, port IO with OUT and INP.

It's super fast by design and written from scratch in Z80 assembly (see the README in the repository for details). Not only does the nqueens benchmark run in only 0.865 seconds, compiling Forth source is speedy too without noticeable delays.

A nice feature of Forth850 is that the size of the free dictionary space is user-definable. This is done by setting USERxxxx in the Monitor to the size of the Forth system. At minimum the system requires 9K e.g. USER23FF to accommodate the 8K executable with minimal stacks and dictionary space. The largest is USER75FF with about 21K of free dictionary space.

I've included a forth850.wav file to load the Forth 850 binary via a cassette interface. I will look into serial later. I need to acquire a serial cable first.

Things that will be nice to add (in progress):

• an additional extended "full version" with additional built-in Forth words
• with an improved command line editor, like Forth500
• ability to load Forth source code from the TEXT editor
• serial IO to communicate via RS232 and load source code
  

- Rob