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Re: Breakpoints


Whenever I have seen gdb step through source, it always uses multiple 's'
packets--- it doesn't set breakpoints at all.

b.g.

David Williams wrote:

> My question is still does GDB need to set more than one breakpoint when
> stepping through source? Thinking about it a little more GDB should have
> all of the information available to decide whether a branch will occur. It
> has the current value of all the registers (esp CCR) so it can work it out
> - the real question is does it use this information?
>
> Dave.
>
> ----------
> From:   Mark Salter[SMTP:msalter@cygnus.com]
> Sent:   Thursday, December 23, 1999 2:09 AM
> To:     kevinb@cygnus.com
> Cc:     davidwilliams@ozemail.com.au; gdb@sourceware.cygnus.com
> Subject:        Re: Breakpoints
>
> >>>>> Kevin Buettner writes:
>
> > On Dec 22,  2:29pm, David Williams wrote:
> >> Does GDB ever need to set more than one breakpoint when stepping through
> >> source code? I have not (as yet) seen this type of behaviour.
>
> > Can the target do a singlestep in hardware or do you have to do
> > software emulation?  If the latter, when you're stepping by machine
> > instruction, you'd need two breakpoints on a conditional branch;
> > one for the branch target, the other for the instruction after the
> > branch.
>
> Even in the latter case, the stub can evaluate the condition of the
> branch to see which way its going to go.
>
> --Mark

--
William A. Gatliff
Senior Design Engineer
Komatsu Mining Systems
To teach is to learn.




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