I found this really interesting thesis on the Roland Supersaw emulation and tried to get it done in Pd.
Unfortunately, there is a part where it is needed to manipulate large numbers like 17019.9518580080 (see page 12) and these can't be handled by Pd vanilla. I tried to round them but the result isn't what is expected. I also tried [expr] and this gave worst results.
So apparently, I have to rely on externals to get this done. Coding one in C is out of reach for me for the now. Would PDlua be able to handle those numbers?