From: Joel Brobecker <brobecker@adacore.com>
To: Chen Gang <gang.chen.5i5j@gmail.com>
Cc: Andreas Schwab <schwab@linux-m68k.org>, gdb-patches@sourceware.org
Subject: Re: [PATCH] gdb/hppa-tdep.c: Fix a logical typo bug found by compiler warning
Date: Wed, 15 Oct 2014 15:00:00 -0000 [thread overview]
Message-ID: <20141015150049.GD25846@adacore.com> (raw)
In-Reply-To: <543D98F3.2030009@gmail.com>
> On 10/15/2014 05:29 AM, Andreas Schwab wrote:
> > Chen Gang <gang.chen.5i5j@gmail.com> writes:
> >
> >> && (((inst >> 6) & 0xf) == 0x8
> >> - || (inst >> 6) & 0xf) == 0x9))
> >> + || ((inst >> 6) & 0xf) == 0x9)))
> >
> > ((inst >> 6) & 0xe) == 8
> >
> > Andreas.
> >
>
> I guess, your fixing may like below, which will be a different logical
> working flow.
I think Andreas is telling you that...
((inst >> 6) & 0xf) == 0x8
|| ((inst >> 6) & 0xf) == 0x9
... is logically equivalent to ...
((inst >> 6) & 0xe) == 8
In other word, if it does not matter if bit 7 is set or not
(the difference between 0x8 and 0x9) all you have to do is mask it.
That way, you test both conditions with one comparison instead of 2.
--
Joel
next prev parent reply other threads:[~2014-10-15 15:00 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-14 21:21 Chen Gang
2014-10-14 21:29 ` Andreas Schwab
2014-10-14 21:43 ` Chen Gang
2014-10-15 15:00 ` Joel Brobecker [this message]
[not found] <d6q0acpdxmm7g52oqylkjjb2.1413419448973@email.android.com>
2014-10-16 7:06 ` Andreas Schwab
2014-10-16 7:38 ` Chen Gang
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=20141015150049.GD25846@adacore.com \
--to=brobecker@adacore.com \
--cc=gang.chen.5i5j@gmail.com \
--cc=gdb-patches@sourceware.org \
--cc=schwab@linux-m68k.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