porting GDB to a new target

[Ramana]

Hi,

   I want to port GDB to AVR on my personnel interest.

I went to through the GDB internals doc and came to know that first i
need to understand the target architecture details, AVR in my case.
But i am not clear on these lines

1. What are the initial steps i should follow to complete this?
2. What target dependency functions i need to implement and what
target details determine
    these?
2. What all target architecture details i should consider and how they
are related to each other
    architecture detail in porting. e.g. call frame implementation
varies with presence/use of
    frame pointer etc
3. Where can i get the target architecture details? mainly i am looking for AVR.

Any online source link would be very helpful.

Thanks in advance.

Regards,
Ram