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From: Will Deacon <will.deacon@arm.com>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Stephen Boyd <sboyd@codeaurora.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"linux-arm-msm@vger.kernel.org" <linux-arm-msm@vger.kernel.org>,
	Stepan Moskovchenko <stepanm@codeaurora.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/3] arm: vfp: Bounce undefined instructions in vectored mode
Date: Fri, 19 Sep 2014 02:40:01 +0100	[thread overview]
Message-ID: <20140919014001.GB20773@arm.com> (raw)
In-Reply-To: <20140918225531.GG5182@n2100.arm.linux.org.uk>

On Thu, Sep 18, 2014 at 11:55:31PM +0100, Russell King - ARM Linux wrote:
> On Thu, Sep 18, 2014 at 02:43:12PM -0700, Stephen Boyd wrote:
> > From: Stepan Moskovchenko <stepanm@codeaurora.org>
> > 
> > Certain ARM CPU implementations (e.g. Cortex-A15) may not raise a
> > floating- point exception whenever deprecated short-vector VFP
> > instructions are executed. Instead these instructions are treated
> > as UNALLOCATED. Change the VFP exception handling code to emulate
> > short-vector instructions even if FPEXC exception bits are not
> > set.
> 
> Purely out of interest, how much use do these instructions have in
> real programs?

They're seldom used, but there are apps in the app store that use short
vectors to play music.

Will

  reply	other threads:[~2014-09-19  1:40 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-18 21:43 [PATCH 0/3] Krait VFP fixes Stephen Boyd
2014-09-18 21:43 ` [PATCH 1/3] ARM: vfp: Workaround bad MVFR1 register on some Kraits Stephen Boyd
2014-09-18 21:43 ` [PATCH 2/3] ARM: vfp: fix VFPv3 hwcap detection on non-ARM vfp implementations Stephen Boyd
2014-09-18 22:46   ` Russell King - ARM Linux
2014-09-19 18:24     ` Stephen Boyd
2014-10-01 17:54       ` Stephen Boyd
2014-10-08 12:49         ` Will Deacon
2014-10-01 21:50       ` Russell King - ARM Linux
2014-10-01 22:09         ` Stephen Boyd
2014-09-18 21:43 ` [PATCH 3/3] arm: vfp: Bounce undefined instructions in vectored mode Stephen Boyd
2014-09-18 22:55   ` Russell King - ARM Linux
2014-09-19  1:40     ` Will Deacon [this message]
2014-09-18 22:32 ` [PATCH 0/3] Krait VFP fixes Russell King - ARM Linux
2014-09-19 16:29   ` Stephen Boyd
2014-09-21 16:40 ` Rob Clark

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