eCos porting to MPC8555 with WiMax board

[madhulingeswara reddy vennapusa]

hai all,
          I am tring to port ecos to MPC 8555 processor with WiMax
board. I found major areas that needs to be change and those are
serial,ethernet drivers, inturrupt handling, memory management. now my
quetions are

Does porting eCos to a new processor depend on both processor and board?
Is there any other areas that need to be change?
I am thinking to use MPC 8260 as base line is it correct or not?
plz some one clear my doubts at the earliest.