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Re: Breakpoints
- To: "davidwilliams at ozemail dot com dot au" <davidwilliams at ozemail dot com dot au>
- Subject: Re: Breakpoints
- From: William Gatliff <gatliff at haulpak dot com>
- Date: Mon, 03 Jan 2000 08:57:36 -0600
- CC: "gdb at sourceware dot cygnus dot com" <gdb at sourceware dot cygnus dot com>
- Organization: Komatsu Mining Systems, Inc.
- References: <01BF4D1C.4AD8ABC0.davidwilliams@ozemail.com.au>
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.