linux-kernel - Re: [PATCH] Reduce the number of expensive division instructions done by _parse

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: <1328805722.6099.5.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC>
Date:	Thu, 09 Feb 2012 17:42:02 +0100
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	David Howells <dhowells@...hat.com>
Cc:	adobriyan@...il.com, torvalds@...ux-foundation.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Reduce the number of expensive division instructions
 done by _parse_integer()

Le jeudi 09 février 2012 à 17:28 +0100, Eric Dumazet a écrit :

> You could avoid the divide and have cleaner code I think.
> 
> 	unsigned long long next = *res * base + val;
> 
> 	if (next < *res)
> 		overflow = 1;
> 	*res = next;
> 

Oh well, this one is better.

        unsigned long long next = *res * base;

        if (next < *res)
                overflow = 1;
        *res = next + val;




--
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/