Backend to start with

Dear Mr. Evan Cheng:

I am adding a new target which is similar to SPARC.
Actually, it does not seem to be a similar one, but I am trying to modify LLVM SPARC backend to make my goal because SPARC looks like the smallest and complete one in the LLVM backend examples. So this is why I had mentioned SPARC.

But, I realized that my question was not appropriate. It looks like my question has no focus such that answer can't be simply replied.
Anyway, thank you.

Seung Jae Lee