Making some progress, but it seems like the ".S" file isn't being looked at a tall. What should link a ".S" file to using the tool specified as the assembler ?
The link is in the "tool" as such the "Cross GCC Assembler". The tool is linked to a file type and in the preferences you can add filename wild cards to file types. The tool decides where to look for files where to put the compilation output.
This is why I made "Arduino C compiler" "Arduino C++ compiler" ....
This is a area I completely rewrote to get everything in 1 eclipse project. The sequence of processing the files is at least "mysterious" so I would not spend to much time trying to plug in assembly only using the gui.
Is inline assembly an option for you?
Best regards
Jantje
Maybe, but it seems a shame the previous functionality (that just worked) has been removed.
I agree it is removed functionality. Getting it to work in one project was a big pain. I had a real hard time and I was sometimes next to hopeless. So now 'm pleased it works. Not including the assembler was a small "cost". I see no reason why I could not add the assembler back in. Apart from
1) I have no test code.
2) I have no need.
Both are things you could help out with

Best regards
Jantje