I've not needed long jumps so far, as I'm only planning to write fairly small ARM functions (poly rasterization), so everything is relocatable so far
As for the ARM emulation, I did a quick test and got my ARM screen clear function running on an x86 build with a bodged version of the ARM core from VisualboyAdvance
I'm wondering if there's a 'GPL workaround' possible by keeping the ARM emulation (and eventual debugging) as a separate program - a GPL'd tool, which could be used to help develop closed-source games if desired.
But the ARM emulator needs access to pretty much all of the target app's data memory... don't really fancy using windows messaging to request individual reads/writes (!!!). Although it would be possible....
I need to read up on Win32 stuff, and see if/how I can get 2 apps to communicate/share memory efficiently...