Re: What would it take....

Da Zheng <[email protected]> Wed, 23 Dec 2009 19:28:35 +0800
Newsgroups gmane.os.hurd.l4,gmane.os.hurd.general,gmane.os.hurd.bugs
Message-ID <[email protected]>
Samuel Thibault wrote:
> Samuel Thibault, le Wed 23 Dec 2009 10:26:09 +0100, a écrit :
>> Da Zheng, le Wed 23 Dec 2009 16:46:34 +0800, a écrit :
>>>> If you use volatile, the compiler won't
>>>> optimise instructions so it would "work" too ; note however that it's
>>>> not SMP safe (it may even not be premption-safe, depending on which
>>>> instruction the compiler eventually uses).
>>> We don't need both? If there is only volatile, instructions might be executed out of order and compilers might also reorder instructions.
>> Volatile prevents from compiler reorder.
> 
> Oops, sorry, of course not. You need the memory clobber for that. Or use
> a function call and not assume that ordering will be correct for local
> variables.
That's what I expect.

Zheng Da