From: "George Spelvin" <linux@horizon.com>
To: linux@horizon.com, mpn@google.com, vda.linux@googlemail.com
Cc: hughd@google.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] lib: vsprintf: Optimize division by 10000
Date: 24 Sep 2012 09:56:14 -0400 [thread overview]
Message-ID: <20120924135614.24704.qmail@science.horizon.com> (raw)
In-Reply-To: <xa1tfw67d24j.fsf@mina86.com>
Michal Nazarewicz <mpn@google.com> wrote:
> Didn't some SPARCs have 32x32->32 multiply? I remember reading some
> rant from a GMP developer about how SPARC is broken that way.
SPARCv9 only has 64x64->64; there's no 128-bit result version.
That cuts large-integer math speed by a factor of 4 (very
crude approximation), to the same speed as 32x32->64.
SPARCv8 UMUL puts the high half of the 64-bit result into the Y
register, and SPARCv7 has a multiply-step instruction (MULScc) which
does likewise.
next prev parent reply other threads:[~2012-09-24 13:56 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-03 5:21 [PATCH 1/4] lib: vsprintf: Optimize division by 10 for small integers George Spelvin
2012-08-03 5:21 ` [PATCH 2/4] lib: vsprintf: Optimize division by 10000 George Spelvin
2012-09-23 17:30 ` Michal Nazarewicz
2012-09-24 12:16 ` George Spelvin
2012-09-24 12:41 ` Michal Nazarewicz
2012-09-24 13:56 ` George Spelvin [this message]
2012-09-24 15:14 ` Geert Uytterhoeven
2012-09-24 15:48 ` George Spelvin
2012-09-24 9:03 ` Denys Vlasenko
2012-09-24 12:35 ` George Spelvin
2012-09-24 15:02 ` Denys Vlasenko
2012-08-03 5:21 ` [PATCH 3/4] lib: vsprintf: Optimize put_dec_trunc8 George Spelvin
2012-09-23 14:18 ` Rabin Vincent
2012-09-24 11:13 ` George Spelvin
2012-09-24 14:33 ` George Spelvin
2012-09-24 14:53 ` Michal Nazarewicz
2012-09-24 14:57 ` Michal Nazarewicz
2012-09-23 18:22 ` Michal Nazarewicz
2012-09-24 11:46 ` George Spelvin
2012-09-24 12:29 ` Michal Nazarewicz
2012-09-24 13:49 ` George Spelvin
2012-09-24 15:06 ` Michal Nazarewicz
2012-09-25 11:44 ` George Spelvin
2012-09-25 13:00 ` Denys Vlasenko
2012-08-03 5:21 ` [PATCH 4/4] lib: vsprintf: Fix broken comments George Spelvin
2012-09-23 17:22 ` [PATCH 1/4] lib: vsprintf: Optimize division by 10 for small integers Michal Nazarewicz
2012-09-24 14:18 ` George Spelvin
2012-09-24 9:06 ` Denys Vlasenko
2012-09-24 11:27 ` George Spelvin
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