Porting Toshiba TLCS-900 - Help

[GSL]

Dear all,
 
I am going to port GCC for Toshiba TLCS-900 
series microcontroller. I studied its source a little bit and I am completely 
lost (too many files). I wonder if someone can give me some 
pointers/hints on doing porting. Any suggestion are very 
welcome.
 
Thanks in advance,
Chi-Chung Liu