You also have to watch out for the "implementation dependent" stuff...packing and ordering.
That was why I did the test software, using the simulator I will reveal my compiler's interworking.
I'm not concerned about compatability at the moment, the same test software has to be done on a different compiler if I need to port it to a different platform.
I personally would store the message in an unsigned long, and mask and shift to get the different fields.
I wonder how would the c compiler treat the bitfields? would it >> and & or would it do it more efficiently. It is exciting to see the output of the compiler in assembly and see how it is done.
Thanks Dennis and Dan, I wonder what Andy have to say?
Mahmood