For those compilers (and most of the assemblers) which don't support straighforward way from the SFR(x,y) definition to an expandable macro, I'd suggest to write a custom preprocessor.

Given the sfr file will have a simple syntax (one definition per line etc.) so it is easy to parse it, to write such a preprocessor is a semitrivial task.

So it will end up as an extra line in the makefile or .bat file.

Just an idea.

Jan Waclawek