Re: (*(unsigned long *)&jiffies)++;

Ingo Oeser (ingo.oeser@informatik.tu-chemnitz.de)
Tue, 11 Jan 2000 10:09:52 +0100 (CET)

On Mon, 10 Jan 2000, Tigran Aivazian wrote:
> On Fri, 7 Jan 2000, Petko Manolov wrote:
> > AFAIK incl _lock_ the bus even without "lock" in fornt of the
> > instruction
> > on 386 machine. Or at least i386 instruction set manual say so.
> > But there is no word about all this in the newest manual i got from
> > Intel. Is this changed on i[56]86?
>
> The section 7.1.2.1 (of Intel PIII, Volume III) says that automatic
> LOCK-ing is done:
>
> * When executing an XCHG instruction that references memory.

ok, but what about the whole family. So i[345]86 and P II, too?
Are any buggy mask revisions known, that break this assumption?

Would be nice instruction for binary semaphores ;) For other
things it doesn't reduce any costs :(

> I know we all can read and cut'n'paste but sometimes it is nice to find
> useful facts in a single email message :)

Agree ;) <Put in persistent archive...>

Regards

Ingo Oeser

-- 
Feel the power of the penguin - run linux@your.pc
<esc>:x




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