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Date: Tue, 25 Feb 2003 14:31:48 -0500 (EST)
From: "Richard B. Johnson" <root@chaos.analogic.com>
Reply-To: root@chaos.analogic.com
To: Daniel Jacobowitz <dan@debian.org>
cc: Linux kernel <linux-kernel@vger.kernel.org>
Subject: Re: atomic_t (24 bits???)
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On Tue, 25 Feb 2003, Daniel Jacobowitz wrote:

> On Tue, Feb 25, 2003 at 02:11:11PM -0500, Richard B. Johnson wrote:
> > 
> > In ../linux/include/asm/atomic.h, for versions 2.4.18 and
> > above as far as I've checked, there are repeated warnings
> > "Note that the guaranteed useful range of an atomic_t is
> > only 24 bits."
> > 
> > I fail to see any reason why as atomic_t is typdefed to a
> > volatile int which, on ix86 seems to be 32 bits.
> > 
> > Does anybody know if this is just some old comments from a
> > previous atomic_t type of, perhaps, char[3]?  
> 
> There are other platforms where you can't reliably use the whole word. 
> Some ARM atomic_t implementations are like this, although I don't know
> if the one in the kernel is.
> 
> -- 
> Daniel Jacobowitz
> MontaVista Software                         Debian GNU/Linux Developer
> 
Okay. Thanks.


Cheers,
Dick Johnson
Penguin : Linux version 2.4.18 on an i686 machine (797.90 BogoMips).
Why is the government concerned about the lunatic fringe? Think about it.


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