From: Richard Henderson <rth@twiddle.net>
To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Anthony Liguori <aliguori@us.ibm.com>,
QEMU Developers <qemu-devel@nongnu.org>,
Gleb Natapov <gleb@redhat.com>
Subject: Re: [Qemu-devel] [PATCH] Fix comparison which always returned false
Date: Tue, 15 Jun 2010 17:27:38 -0700 [thread overview]
Message-ID: <4C181A7A.7040107@twiddle.net> (raw)
In-Reply-To: <4C17F075.7010606@codemonkey.ws>
On 06/15/2010 02:28 PM, Anthony Liguori wrote:
> On 06/15/2010 04:03 PM, Stefan Weil wrote:
>> Comparing an 8 bit value with ~0 does not work as expected.
>> Replace ~0 by UINT8_MAX in comparison and also in assignment
>> (and fix coding style, too).
>>
>
> Because when the uint8_t gets promoted, it doesn't get zero filled. I'd
> rather something a bit more obvious like HPET_INVALID_COUNT.
Er, yes it does. The problem is that it *did* get zero-extended,
but ~0 is 0xffffffff, so the comparison fails.
But I really agree with Jan Kiszka down-thread -- why do we need
to signal this as a special case at all?
r~
next prev parent reply other threads:[~2010-06-16 0:28 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-15 21:03 [Qemu-devel] [PATCH] Fix comparison which always returned false Stefan Weil
2010-06-15 21:28 ` Anthony Liguori
2010-06-16 0:27 ` Richard Henderson [this message]
2010-06-16 12:34 ` Anthony Liguori
2010-06-15 21:28 ` [Qemu-devel] " Jan Kiszka
2010-06-16 4:30 ` Gleb Natapov
2010-06-15 21:41 ` [Qemu-devel] " malc
2010-06-15 21:44 ` malc
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