Re: single-stepping remote target fails

Ramana Radhakrishnan
2005-06-23T16:57:40Z

On Thu, 2005-06-23 at 11:40 -0400, Chad Phillips wrote:
> >On Thu, Jun 23, 2005 at 11:18:28AM -0400, Chad Phillips wrote:
> >> Problem 1.
> >> Single stepping in C source only steps by single machine instruction.
> >> I had expected that GDB might try to set breakpoints on the next
> >> instruction and then continue, but I see no such requests from GDB.
> >> How does GDB cause single steps through C (any high level language)
> >> source?
> >It does hardware single steps until the source line of the $pc changes.
>
> Interesting. It makes no requests to set breakpoints. If I explicitly
> set breakpoints, they work. But when I issue the step command, I get
> no breakpoint commands at my proxy application from GDB. Any Ideas?

Can your stub single step by itself without the debugger ? Guess you can
do with the JTAG on. Does your remote stub support the single stepping
packet ?

In any case do a set debug remote 1 just before you single step and
paste the output log over here. That could help answering.

cheers
Ramana

>
> >> Problem 2.
> >> When I issue the step command (or si, n, ni) to the target, GDB does
> >> a _lot_ of memory reads. It reads from the start of main up to the
> >> current PC (in main). What is it doing, and how can I make it stop?
>
> >Preumably it is doing prologue analysis. You need to work out (A) why
> >it triggered the prolgoue analyzer and (B) whether you should be using
> >unwind information instead of prologue analysis.
>
> Thanks. That make sense.
>
> -Chad