*** M E M O R U M ***

Like Martin, I wrote my own assembler. In my case it runs under CP/M on the MTX, and is self-hosting (it can assemble itself). Fairly crude compaired to what is avalable today, but good enough for what I wanted, and the right price. Dave has a copy at http://primrosebank.net/computers/cpm/cpm_mtx_us...

Agreed, so USERNOD allows extensions to the NODDY language, but not so much for display enhancements. From my quick scan of Martin's full ROM listing, it looks as though NODDY used VS5, so by changing this before calling PLOD it might be possible to change the colours used. However this is a text mo...

System variable USERNOD (0xFAA1). Presumably called at some point in NODDY processing. No idea what you can do with it.

Bill.

One of the issues with using the MTX assembler is that the location of the code changes depending upon the size of the machine being used. This has two implications: 1. When using the USR() function to call the assembler, you have to use a system variable to determine the correct address. I managed ...

I don't do facebook, so I have no opinion as to what is there, However, I'm not sure that even the forum is a good long term place for technical information. At the moment the MTX forum is not very busy, but I also lurk on the Raspberry Pi forum, and there the good technical stuff is prone to get lo...

Having worked out where the MTX BASIC variables are hiding in memory, a little bit of machine code provides a reasonable speed-up of my game. It is still not fast, but the new version (attached) is not quite as slow.

Bill.

Dave,

Feel free to post this on your site if you wish, It is probably more findable there long term.

Either post my PDF or turn it into a web page. Drop me an email if you want the editable version (Libre Office or I can save it as Word).

Bill.

The variable name table and variable values table are both in high memory above 0xC000 and so are restricted to less than 16KB in total (the system variables etc. are also in high memory). This could be a limitation in some cases. The "virtual memory" contains in order: BASIC Listing NODDY...

I have been trying to understand exactly where and how MTX BASIC stores the values of its variables in memory. As far as I know this has not been fully documented (Dave will undoubtedly correct me if I am wrong). The attached document records what I have concluded so far. Paul Daniels has obviously ...

Mark, If you want to avoid reflections in the coax, the source and destination impedances must match the characteristic impedance of the cable. See, for example, http://en.wikipedia.org/wiki/Reflections_of_signals_on_conducting_lines. It may be that for 9.6kb or even 19.2kb serial transmission over ...