Re: next

[Jeremy Bennett <jeremy.bennett@embecosm.com>]

On Thu, 2009-07-02 at 16:39 +0530, nagaraju.m wrote:
> Hi all,
> 
>     I have ported gdb-6.8 to my target. But when i am debugging using 
> new gdb i found that Next command is not working. Even i use next it is 
> just single stepping...
> 
>     Can any one please help me out.
> 
> Thanks in advance,
> Nagaraju.M

Hi Nagaraju,

I ran into the same problem with a port of GDB I did last year. From
memory, in that case, the problem was with my prologue analysis, giving
GDB some very strange information, which confused "next".

How do "step", "stepi" and "continue" behave for you?

If you are connecting to your target remotely, you can glean a lot of
information by looking at the Remote Serial Protocol (RSP) packet
exchanges. "next" may use some single instruction stepping if it thinks
it is currently in a function prologue or the middle of a high level
instruction, to get to the clean start of a high level instruction. It
will then set a breakpoint after that high level instruction and run to
that breakpoint. "next" could be failing if it can't single step, or it
can't get reliable information about the start of high level
instructions or end of function prologues, or if breakpoints aren't
working correctly.

I wrote an application note last year on RSP, which has some GDB client
function traces for various GDB commands. I didn't include "next", but
"step" and "continue" may help you.

        http://www.embecosm.com/download/ean4.html

Hope this is useful.


Jeremy

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