The address of a function is not fixed before files are linked. So I am not able to set the address of trap instructions before linking.
If I set the address for every trap instructions one by one ( by hand :-) ), it is a very tired job for there are many functions and there should be many traps.
And the thing become more trouble because wherever I insert some instructions, all of later functions' addresses shoule be adjusted. So I should link the files again.
Then insert a trap after a function,then link again ,then insert again.....
Is there a more efficient idea?