Re: An article about the Cygnus tree

["Russ.Shaw" <russell@webaxs.net>]

I think there should be a newsgroup for the gnu tools etc, for applications
involving embedded systems. comp.arch.embedded is more hardware oriented.
What about a comp.gnu.embedded for all questions on installation, development,
use, and abuse of gnu/cygnus/open-source tools for embedded systems?


Michael Sokolov wrote:
> 
> And while I think this is stated clearly enough in the article itself, let me
> repeat: the previous point (that I wasn't even sure what to call it) is the
> essense of the problem that needs a solution: there is a sore lack of public
> tutorial information on this animal. There is a home for the GNU project and
> there are home pages for all GNU projects, and as a result, everyone knows what
> they are and where to get them. But it's very hard to explain to a newcomer
> what the Cygnus tree is. See below.
> 

-- 
*******************************************
*   Russell Shaw, B.Eng, M.Eng(Research)  *
*      email: russell@webaxs.net          *
*      Victoria, Australia                *
*******************************************
From eliz@delorie.com Mon Sep 04 22:49:00 2000
From: Eli Zaretskii <eliz@delorie.com>
To: hjl@lucon.org
Cc: kettenis@wins.uva.nl, gdb@sourceware.cygnus.com
Subject: Re: gdb doesn't work very well with dynamic linked binaries
Date: Mon, 04 Sep 2000 22:49:00 -0000
Message-id: <200009050548.BAA05890@indy.delorie.com>
References: <20000901192328.A28312@valinux.com> <200009041047.LAA10659@phal.cygnus.co.uk> <20000904084934.A11100@lucon.org> <200009041751.e84HprD11517@debye.wins.uva.nl> <20000904164458.A12270@lucon.org>
X-SW-Source: 2000-09/msg00025.html
Content-length: 1721

> 
> Date: Mon, 4 Sep 2000 16:44:58 -0700
> From: "H . J . Lu" <hjl@lucon.org>
> 
> 1. Delete hardware watchpoints to free hardware debug registers. Set 4
> hardware watchpoints. Then delete/disable one hardware watchpoint. Set
> another hardware watchpoint. Can gdb free a hardware debug register
> when I delete/disable the hardware watchpoint which uses it?
> 2. Watch for different values on a viariable with one hardware debug
> register. That is do
> 
> (gdb) watch foobar == 1
> (gdb) watch foobar == 2
> (gdb) watch foobar == 3
> (gdb) watch foobar == 4
> (gdb) watch foobar == 5
> 
> only using one hardware debug register.
> 
> I have reported them long before 5.0 was released. But at least #1
> still doesn't work right in 5.0 under Linux/ia32.

These are not GDB/ia32 issues per se: the above features are all
implemented in the DJGPP port of GDB and work in v5.0.  Every
x86-based target should be able to lift the relevant parts of
go32-nat.c and use them almost verbatim.  You get debug register
sharing through reference counts, and the ability to watch large
regions (up to 16 bytes) using multiple registers.  (The required
infrastructure in high-level GDB application code, mostly in
breakpoint.c, is also working since v5.0.)

What is missing is something that we discussed here some time ago: a
unified handling for debug registers common for ALL ia32 targets.  If
you want to get this done before 5.1 is out, I'm for it.  I said in
the past that I'm willing to volunteer to pull the code out of
go32-nat.c and generalize it as appropriate, as the first step towards
this goal.  Provided that it's decided to do that for 5.1, of course
(otherwise, I have too many other important things to do ;-).