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Re: Display of read/access watchpoints when HAVE_NONSTEPPABLE_WATCHPOINT
- From: Ulrich Weigand <weigand at i1 dot informatik dot uni-erlangen dot de>
- To: pkoning at equallogic dot com (Paul Koning)
- Cc: weigand at i1 dot informatik dot uni-erlangen dot de, orjan dot friberg at axis dot com, kettenis at chello dot nl, gdb-patches at sources dot redhat dot com, eliz at gnu dot org, drow at false dot org
- Date: Thu, 6 May 2004 23:38:02 +0200 (CEST)
- Subject: Re: Display of read/access watchpoints when HAVE_NONSTEPPABLE_WATCHPOINT
> My experience was that the old code worked if you had only a
> watchpoint active, but it would produce the wrong results if you had
> both watchpoints and breakpoints active. The reason was that the scan
> for matching break/watch points would conclude that the target break
> had happened due to a non-matching watchpoint and would proceed,
> rather than break.
But this error scenario should only apply to read/access watchpoints,
never write watchpoints. A write watchpoint should never be misdetected ...
> That doesn't seem like a good idea. Why would it be reasonable to
> treat the two differently?
Because a write watchpoints can be handled without hardware support to
provide the address, while read/access watchpoints fundamentally
cannot be.
Bye,
Ulrich
--
Dr. Ulrich Weigand
weigand@informatik.uni-erlangen.de