ARM Data Abort error exception debugging
So now I understand that I'm getting a ARM Data Abort exception - I see how to trap the exception itself (a bad address in the STL library), but I would like to walk back up the stack frame before the exception. I'm using the IAR toolchain, and it tells me the call stack is unavailable after the exception - is there a trick way to convince the tool to show me the call stack? Thanks for all the quick help!
Answer
if you look at the ARM ARM (ARM Architecture Reference Manual, just google "arm arm"), Programmers Model -> Processor modes and Registers sections. When in abort mode you are priveledged so you can switch from abort to say supervisor and then make a copy of r13, then switch back to abort mode and dump the stack from the copy of r13. Your r14 also tells you where the abort occurred.
I wouldnt be surprised if this abort was from an alignment. Trying to read/write a word with an address with something other than zeros in the lower two bits or a halfword with the lsbit of the address set. Actually if you take the link register and a dump of the registers (r0-r12) since abort and user/supervisor use the same register space, you can look at the instruction that caused the abort and the address to see if it was indeed an alignment problem or something else. Note that the pc is one, two or three instructions ahead depending on the mode thumb or arm that had the abort, if you are not using thumb at all then this nothing to worry about.