support for multiple ARM register banks in GDB

support for multiple ARM register banks in GDB

[Brendan Kehoe]

Hi folks,

Is anyone already looking at GDB's port to the ARM, and in particular
what it believes is the single register bank on the chip?  For
processors like the ARM7TDMI, there are a few register banks depending
on the current mode of the ARM.  In order to debug (not C++) exceptions
on an ARM embedded target, it's necessary to be able to look at a
specific bank's register like r13_irq.  This sort of stuff appears to be
in place in the simulator, but not in GDB itself.

I'm curious if the ARM support under GDB mainly intended for RTOS-based
stuff, versus full-fledged embedded development?  (sic)

Thanks for any tips,
B

Re: support for multiple ARM register banks in GDB

[Daniel Jacobowitz]

On Thu, May 11, 2006 at 03:50:37PM +0100, Brendan Kehoe wrote:
> Hi folks,
> 
> Is anyone already looking at GDB's port to the ARM, and in particular
> what it believes is the single register bank on the chip?  For
> processors like the ARM7TDMI, there are a few register banks depending
> on the current mode of the ARM.  In order to debug (not C++) exceptions
> on an ARM embedded target, it's necessary to be able to look at a
> specific bank's register like r13_irq.  This sort of stuff appears to be
> in place in the simulator, but not in GDB itself.

I've implemented banked register support, as a sample application of
the XML-based register description work I've posted about several
times.  The GDB client and the RDI-based GDB stub we ship in
the 2006-Q1 CodeSourcery release includes support for banked registers.
Of course, if your target isn't RDI-based, that doesn't directly help
you.  But it shouldn't be hard to do for a custom debug stub either.

(It took all of an hour or two once the XML bits were in place, so I'd
say it was a successful test run).

-- 
Daniel Jacobowitz
CodeSourcery

Re: support for multiple ARM register banks in GDB

[Mark Kettenis]

> Date: Thu, 11 May 2006 15:50:37 +0100
> From: Brendan Kehoe <brendan@zen.org>
> 
> I'm curious if the ARM support under GDB mainly intended for RTOS-based
> stuff, versus full-fledged embedded development?  (sic)

Dunno if it answers your question, but OpenBSD/arm is fully supported
as a native target, and OpenBSD isn't an RTOS!  It isn't an embedded
OS either.

Mark