linux-kernel - Re: The type of bitops

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <51885AA0.4090807@zytor.com>
Date:	Mon, 06 May 2013 18:36:32 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
CC:	linux-arch <linux-arch@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: The type of bitops

On 05/06/2013 05:51 PM, Linus Torvalds wrote:
> 
>> 4. Do some macro hacks so the bitops are dependent on the size of the
>>    argument.
> 
> That sounds insane. Just *how* could the size of the argument even
> matter? Seriously, there's no *difference* between a 32-bit or a
> 64-bit index. The code is the same, there's no possible reason to make
> it be different.
> 

The only reason on x86 would be to avoid the REX prefix.  Hardly worth
it, though.

	-hpa

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/