How to create/add a new address space in a Loader?

[hippietrail]

I'm making some loaders for the '80s microcomputer the TI-99/4A which had an unusual architecture.

As well as the usual address space the CPU can access with ROM and RAM it also had a "GROM" address space which was graphics RAM and where byte code called GPL (graphics programming language) resided. I want to add a "GROM" address space.

I don't usually program in Java. I can find protected addAddressSpace() member function in DefaultAddressFactory.java but since it's protected I can't call it. The only code I can find which does use it is in GadpClient.java and VarnodeContext.java, which both extend DefaultAddressFactory

This is getting too far down the Java rabbit hole for me and my naïve attempts to implement it are failing. I can't find any Ghidra Loader which adds an additional address space either.

[ryanmkurtz]

Address spaces are defined by a processor, not a loader. So, it will have to be added to your TI-99/4A processor module (.slaspec file) for Ghidra to know about it.

[hippietrail]

Ah I started thinking it could be something like that. This is an odd platform and the CPU can't access the GROM address space. It communicates via a couple of hardware registers.
I'm not sure if a better approach could be to define an abstract processor that wraps both the CPU and the GROM+GPL. Or maybe it would need a .slaspec for the TMS990 CPU and another for the GROM+GPL. I haven't looked at how loaders for platforms with multiple different processors work. Maybe it's simply not a good fit for Ghidra.