Psion Organiser II Assembler

Looking for PSION Organiser II Software
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amenjet
Posts: 43
Joined: Sun Aug 22, 2021 6:56 am

Psion Organiser II Assembler

Post by amenjet »

I don't know if anyone is interested but I have just made the repository for an assembler I wrote a while back public.
When I was working on the top slot adapter PCB I needed to create some assembly language to run on the organiser and access the IO ports.
The Psion assembler runs on DOS so I decided to take time out to write an assembler for the 6303 that can output the relocatable code that the
organiser uses. It's written in Tcl so should be portable to any almost machine. It's just one file so easy to copy places.
It supports macros and expressions. Not all directives from the original Psion assembler are supported, just enough to assemble the XDICT example
that Psion gave. It should be pretty easy to add any missing directives.

It's pretty fast, even though it is a four pass assembler. If you do decide to assemble the XDICT code you will find that this assembler give slightly smaller code as it generates minimal code for all instructions, unlike the Psion assembler which, for some unknown reason used a 16 bit address for accessing a memory location that could be accessed using zero page accesses.

The top slot adapter:
https://youtu.be/OjPG9-fXxJ4
https://youtu.be/E4JlnzxkZ0U

The repository for the assembler
https://github.com/blackjetrock/psion-org2-assembler

Andrew
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