From: Jan Kratochvil <jan.kratochvil@redhat.com>
To: Joel Brobecker <brobecker@adacore.com>
Cc: Eli Zaretskii <eliz@gnu.org>, gdb-patches@sourceware.org
Subject: Re: [patch 3/4] Fix hw watchpoints #2: reordered / simultaneously hit
Date: Tue, 17 Nov 2009 15:31:00 -0000 [thread overview]
Message-ID: <20091117152912.GA29979@host0.dyn.jankratochvil.net> (raw)
In-Reply-To: <20091117141139.GA5266@adacore.com>
On Tue, 17 Nov 2009 15:11:39 +0100, Joel Brobecker wrote:
> > ??? Why? What's wrong with bitfields that we should avoid them?
>
> It makes access to the field more difficult and require more instructions.
While true...
0000000000000000 <get>:
0: 0f b6 47 04 movzbl 0x4(%rdi),%eax
+ 4: 83 e0 01 and $0x1,%eax
c3 retq
0000000000000010 <set>:
- 10: c6 47 04 01 movb $0x1,0x4(%rdi)
+ 10: 80 4f 04 01 orb $0x1,0x4(%rdi)
... one may miss turning it to a flag for sharing the byte for other flags in
future possibly creating the struct needlessly larger.
But OK.
Regards,
Jan
next prev parent reply other threads:[~2009-11-17 15:31 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-16 3:42 Jan Kratochvil
2009-11-17 0:12 ` Joel Brobecker
2009-11-17 4:03 ` Eli Zaretskii
2009-11-17 14:13 ` Joel Brobecker
2009-11-17 15:31 ` Jan Kratochvil [this message]
2009-11-17 19:18 ` Eli Zaretskii
2009-11-17 19:42 ` Joel Brobecker
2009-11-17 22:18 ` Eli Zaretskii
2009-11-17 19:20 ` Eli Zaretskii
2009-11-18 10:09 ` Jan Kratochvil
2009-11-18 11:36 ` Pedro Alves
2009-11-20 16:58 ` Pedro Alves
2009-11-20 17:06 ` Pedro Alves
2009-11-20 17:15 ` Jan Kratochvil
2009-11-20 17:10 ` Daniel Jacobowitz
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20091117152912.GA29979@host0.dyn.jankratochvil.net \
--to=jan.kratochvil@redhat.com \
--cc=brobecker@adacore.com \
--cc=eliz@gnu.org \
--cc=gdb-patches@sourceware.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox