Hi enribarb, I think that .rel files ("relocatable" ) of SDCC
are conceptually the same as .o files: relocatable binary code
ready to be linked into an executable.
I know you asked for something else, it's just to let you know
of this possible alternative: some time ago I have configured
my Eclipse IDE to compile with SDCC and GNU make. Here are
the steps I followed:
andrear.altervista.org/home/sdcceclipse.php
(to be honest: that configuration required a bit too much
effort, but I think in the end you get a good tool that helps
your writing with highlighting/references/etc.)
Don't punch me, but for MSX C code I use Visual Studio (the tool I know most since I use it at work), and sometimes even a plain text editor; then I compile by invoking a batch file from a command line window...