Message-ID: <508870D4.6010104@zytor.com>
Date: Wed, 24 Oct 2012 15:51:00 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Juri Lelli <juri.lelli@gmail.com>
CC: peterz@infradead.org, tglx@linutronix.de, mingo@redhat.com,
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        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Ingo Molnar <mingo@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 02/16] math128, x86_64: Implement {mul,add}_u128 in 64bit
 asm
References: <1351115634-8420-1-git-send-email-juri.lelli@gmail.com> <1351115634-8420-3-git-send-email-juri.lelli@gmail.com> <50886B43.3080001@zytor.com> <50886FFB.8070802@gmail.com>
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On 10/24/2012 03:47 PM, Juri Lelli wrote:
>>
>> How could this work since u128 presumably has not yet been defined as a
>> structure?  After all, isn't it the absence of ARCH_HAS_INT128 which
>> makes that happen?
> 
> Sorry, you were not in the Cc list of the previous patch in the patchset,
> so you probably missed that. I should have triple checked git send-email
> Cc list. Sorry about that.
> 
> I'll add you there.
> 

Hmm... you realize that at least on some platform the u128 as a union is
going to perform worse than the plain __int128, right?  As such IMO it
would be better if the union was only defined if needed.

	-hpa

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