From: "Måns Rullgård" <mans@mansr.com>
To: Matt Sealey <neko@bakuhatsu.net>
Cc: "Stephen Boyd" <sboyd@codeaurora.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Jean-Christophe PLAGNIOL-VILLARD" <plagnioj@jcrosoft.com>,
"Christopher Covington" <cov@codeaurora.org>,
"Russell King - ARM Linux" <linux@arm.linux.org.uk>,
"Måns Rullgård" <mans@mansr.com>,
"Rob Herring" <robherring2@gmail.com>
Subject: Re: [PATCH v2] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions
Date: Sat, 09 Nov 2013 18:20:38 +0000 [thread overview]
Message-ID: <yw1x38n5wi6h.fsf@unicorn.mansr.com> (raw)
In-Reply-To: <CAHCPf3tCTUEX6oDLUndZwt=Hk+YxsKjPO96N=Zhx82+_LM66sQ@mail.gmail.com> (Matt Sealey's message of "Sat, 9 Nov 2013 00:46:11 -0600")
Matt Sealey <neko@bakuhatsu.net> writes:
> BTW has there been any evaluation of the penalty for the extra
> branching, or the performance hit for the ARMv7-without-division
> cases?
The branches themselves probably have minimal overhead. There will
however be code to preserve call-clobbered registers (and move the
values to/from r0/r1) that would not be needed if the div instructions
were done inline (obviously such a kernel could only run on hardware
with division support).
--
Måns Rullgård
mans@mansr.com
next prev parent reply other threads:[~2013-11-09 18:20 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-08 23:00 Stephen Boyd
2013-11-09 6:46 ` Matt Sealey
2013-11-09 18:20 ` Måns Rullgård [this message]
2013-11-12 1:23 ` Stephen Boyd
2013-11-10 5:03 ` Nicolas Pitre
2013-11-12 2:34 ` Stephen Boyd
2013-11-12 11:28 ` Måns Rullgård
2013-11-12 14:01 ` Nicolas Pitre
2013-11-12 14:04 ` Russell King - ARM Linux
2013-11-12 14:16 ` Nicolas Pitre
2013-11-12 14:17 ` Ben Dooks
2013-11-12 14:32 ` Nicolas Pitre
2013-11-12 14:40 ` Måns Rullgård
2013-11-12 14:55 ` Nicolas Pitre
2013-11-12 15:20 ` Nicolas Pitre
2013-11-12 18:03 ` Måns Rullgård
2013-11-12 14:22 ` Måns Rullgård
2013-11-12 14:36 ` Nicolas Pitre
2013-11-11 7:46 ` Uwe Kleine-König
2013-11-12 2:35 ` Stephen Boyd
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