porting gcc to a different architecture

[Marco Marcello]

Hi, I have to modify gcc to use it with an ARM-based architecture with
some coprocessors...
I have some knowledge about C,C++, assembly and the ARM instruction set,
but I don't know how gcc works...
can anybody tell me which files I have to modify to adapt the ARM gcc
compiler?
well the difference is that I have to map some operations on the
coprocessors
Thanx a lot