8-bit acorn software: other • Re: Running a Program from ROM / Sideways Rom

The big question here is "Do you have the source code?"
If you do, although a service ROM has an additional layer of complexity over a simple assembler program, in that it needs a header and a routine to respond to a call for unrecognised commands, this is fairly simple stuff and JGH may even have a program that can generate something.

If you don't, then you have two options:

• Put it in ROM for easy access but have it copied to the original location in memory when it needs to run. There are at least two ways to do this:
  • Use the ROM filing system as already mentioned. The advantage of that is that it is easier and there is a tool to automate it. It is probably also more tube-compatible. The disadvantage is the ROMFS is fairly slow and you need to selected it first, with *ROM, before you can run files from it.

[*]Write a wrapper that copies the code from ROM down to its original location in RAM and which responds to the unrecognised ROM service call. That would execute faster and work even when DFS or TAPE was the selected filing system. If you wanted to support the tube, though, you'd have to go to some trouble to do that.

Statistics: Posted by jgharston — Tue Jan 16, 2024 12:18 am