From: Jeffrey Walton <noloader@gmail.com>
To: Kostas Savvidis <ksavvidis@gmail.com>
Cc: "gcc-help@gcc.gnu.org" <gcc-help@gcc.gnu.org>
Subject: Re: 128-bit integer - nonsensical documentation?
Date: Wed, 26 Aug 2015 11:44:00 -0000 [thread overview]
Message-ID: <CAH8yC8ndCNLA62k6mNMO80TOfrE_3-wXsz2oy=rqQaU1cL90QQ@mail.gmail.com> (raw)
In-Reply-To: <1B1111BE-E274-4C80-8189-22B78D77647A@gmail.com>
On Wed, Aug 26, 2015 at 7:04 AM, Kostas Savvidis <ksavvidis@gmail.com> wrote:
> The online documentation contains the attached passage as part of the "C-Extensions” chapter. There are no actual machines which have an " integer mode wide enough to hold 128 bits” as the document puts it. This would be a harmless confusion if it didn’t go on to say “… long long integer less than 128 bits wide” (???!!!) Whereas in reality "long long int” is 64 bits everywhere i have seen.
>
On 64-bit platforms, a 128-bit integer is available. I don't know how
widespread it is, but its available on the Intel Mac I use and some of
my P4 machines.
When using OpenSSL, if you configure with enable-ec_nistp_64_gcc_128,
then Elliptic Curve Diffie-Hellman is about 2x to 4x faster. You have
to enable enable-ec_nistp_64_gcc_128 manually because OpenSSL's
configure cannot detect it. See, for example
https://wiki.openssl.org/index.php/Compilation_and_Installation.
Jeff
next prev parent reply other threads:[~2015-08-26 11:44 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-26 11:04 Kostas Savvidis
2015-08-26 11:44 ` Jeffrey Walton [this message]
2015-08-26 12:13 ` David Brown
2015-08-26 16:02 ` Martin Sebor
2015-08-27 7:12 ` David Brown
2015-08-27 9:32 ` Jonathan Wakely
2015-08-27 9:42 ` Marc Glisse
2015-08-27 9:43 ` Jonathan Wakely
2015-08-27 15:09 ` Martin Sebor
2015-08-28 6:54 ` David Brown
2015-08-28 15:30 ` Martin Sebor
2015-08-26 12:22 ` Jonathan Wakely
2015-08-26 12:32 ` Kostas Savvidis
2015-08-26 12:39 ` Jonathan Wakely
2015-08-26 12:47 ` Jeffrey Walton
2015-08-26 12:47 ` David Brown
2015-08-26 12:48 ` Jeffrey Walton
2015-08-26 12:51 ` Marc Glisse
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