Re: ARM7, remote GDB, Software Breakpoints

[Quality Quorum <qqi@theworld.com>]

On Wed, 12 Feb 2003, Torsten Mohr wrote:

> Hi,
>
> thanks for your hint.
>
> > > 1. I could handle HW breakpoints, how can i tell GDB that it should
> > > use HW breakpoints?  Just answering requests for SW breakpoints with
> > > "ENN" doesn't seem to make GDB use HW breakpoints.
> >
> > You have to implement commands starting with 'Z' and 'z' in order to
> > support hw breakpoints.
>
> Yes, i do that.  According to GDB remote protocol, when i answer
> a request for "Z0..." with "ENN" (means "i can't handle software
> breakpoints"), GDB doesn't try hardware breakpoints.

As far as understand in order to set hw-breakpoint, user should explicitly
say that he/she wants hw-breakpoint (I do not remember precise syntax), '
'breakpoint' is always a software breakpoint.

>
> But maybe, when i have some hardware that doesn't run in RAM,
> but in Flash-ROM, i think i'd rather like to have HW breakpoints.
> Also, when i don't answer with "ENN", but with "" (empty),
> GDB doesn't try HW breakpoints.
>
>
> > It is very strange, because gdb works exactly this way. I am wondering do
> > you have 'step' command implemented?
>
> Oops, my misinterpretation of that protocol.  Yes, it just works
> as it is.  Great.
>
>
> > > 3. Thumb mode is not handled at all at the moment, what do i need
> > > to do to handle Thumb mode?
> > > If GDB downloads a program into the target and sets the PC to a
> > > certain address, how does my server know if it should execute this
> > > in ARM or in Thumb mode?
>
>
> Thanks,
> Torsten.
>

Thanks,

Aleksey