From mboxrd@z Thu Jan  1 00:00:00 1970
From: jtc@redback.com (J.T. Conklin)
To: markom@opencores.org
Cc: gdb@sources.redhat.com
Subject: Re: HW breakpoints, watchpoints and trace
Date: Thu, 17 May 2001 10:31:00 -0000
Message-id: <5mheyjubks.fsf@jtc.redback.com>
References: <3B022218.5A59D75F@opencores.org>
X-SW-Source: 2001-05/msg00293.html

>>>>> "Marko" == Marko Mlinar <markom@opencores.org> writes:
Marko> I have a question: Our processor (or1k) has a lot of HW
Marko> debugging capabilities and I was wondering what would be the
Marko> best solution to include them into user interface.

Marko> e.g.: We can create HW watchpoint as
Marko> "watchpoint_event" = $1234 == 506 && ( $50 > 70 && $50 <= 120
Marko> || !write_to_address_occured (4567))

Marko> (Sorry about this freaky pseudo code, but I hope you get my
Marko> point) 

Actually, I'm a bit confused.

Marko> We could surely add special command which would support such
Marko> functionality, but I would like to have this functionality
Marko> detected automaticaly using break or hbreak.

Note that GDB already supports hardware watchpoints on several
targets.  See the watch, awatch, and rwatch commands for details.

The low-level guts of GDB only supports read, write, or access watch-
points on memory locations, but the high level CLI takes expressions.
So with "watch foo > 3", GDB would get an event when "foo" is changed,
and then it would evaluate "foo > 3".  

>From your above pseudo code, it appears that the or1k processor might
be able to evaluate the entire expression.  GDB has no support for such
a thing.  I suggest getting basic hardware watchpoints working before 
taking on such a project.

        --jtc

-- 
J.T. Conklin
RedBack Networks