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Date: Thu, 25 Jul 2002 00:39:44 +0100
From: Jamie Lokier <lk@tantalophile.demon.co.uk>
To: Linus Torvalds <torvalds@transmeta.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: type safe lists (was Re: PATCH: type safe(r) list_entry repacement: generic_out_cast)
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Linus Torvalds wrote:
> >> As long as your pointers are 32bit this seems to be ok. But on 
> >> 64bit implementations pointers are not (unsigned long) so this cast 
> >> seems to be wrong.
> >
> >A pointer fits into unsigned long on all 64bit linux ports.
> >The kernel very heavily relies on that.
> 
> Not just the kernel, afaik.  I think it's rather tightly integrated into
> gcc internals too (ie pointers are eventually just converted to SI
> inside the compiler, and making a non-SI pointer would be hard). 

That can't be the case, as how would GCC represent 64-bit pointers on
platforms like the Alpha, which support 64-bit, 32-bit, 16-bit and 8-bit
types?  64-bits must be DImode simply because QImode is the smallest
mode, and required for the 8-bit type.

-- Jamie

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