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Date: Tue, 15 Jun 2010 17:27:38 -0700
From: Richard Henderson <rth@twiddle.net>
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Subject: Re: [Qemu-devel] [PATCH] Fix comparison which always returned false
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To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Anthony Liguori <aliguori@us.ibm.com>, QEMU Developers <qemu-devel@nongnu.org>, Gleb Natapov <gleb@redhat.com>

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~