Using f9dasm to decompile 4051 cartridge code

[WaveyDipole]

Dave, thanks. Yes that does make sense and I appreciate the clarification as to what 'pseudo' means in this instance. I did wonder whether it something like that and whether certain memory locations were used for multiple purposes as in your explanation of REGISTER13 vs DIMSUBSCRIP as well as registers holding a single 16-bit value vs two 8-bit ones. I will have to consider how to lay out the information in my document.

 

[daver2]

No problem.

Dave

 

[Vermithrax]

Monty:

I noticed that the [MMMM];J (Jump) command seems to work in most 4051 emulations that load DEBUG through the EXEC function, but not in in Falter's version of the 4051 Emulator with Board Bucket DDT.

I want to look more closely into the disassembly, but I was also looking for the BASIC command that lists the expansion ROM calls.

Do you recall what that command is?

Nelson

 

[nikola-wan]

CALL "CLIST" works on a 4051 and the 4051 emulator but it requires the vintagetek.org MAXIROM pack which has 4051 Enhanced BASIC (never released to production) with that CALL.

There is no CLIST call in the 4051 BASIC ROM, nor in the 4052 or 4054 BASIC ROMs.

The 4052A and 4054A have an undocumented CALL "CLIST" (underscored characters are control characters) that was finally published in a Tekniques article.

Only other way to find expansion ROMs in any 4050 computer is to try one of the CALLs. I use this in my Tektronix 4050 GPIB Flash Drive main menu program during first time setup to detect specific option ROMs so I can disable main menu selections that won't run due to missing option ROMs.

Use the 4051 option ROM user manuals at http://www.bitsavers.org/pdf/tektronix/405x/ to pick a CALL to use.