RE: SDIV / UDIV Question

From: Wang, Yalin
Date: Thu Oct 10 2013 - 01:04:53 EST


Hi Will ,


Oh , I see ,
Thanks for your clarification !
So R-class cores will not run linux ?
This means we don't need care about this .
Am I right ?

Thank you .

-----Original Message-----
From: Will Deacon [mailto:will.deacon@xxxxxxx]
Sent: Wednesday, October 09, 2013 6:54 PM
To: Wang, Yalin
Cc: 'linux-arm-msm-owner@xxxxxxxxxxxxxxx'; linux-kernel@xxxxxxxxxxxxxxx
Subject: Re: SDIV / UDIV Question

On Wed, Oct 09, 2013 at 08:08:05AM +0100, Wang, Yalin wrote:
> I have a question about sdiv/ udiv instructions :
> In armv7 A/R TRM, it said sdiv/udiv will cause Divide by zero as
> undefined exception or just return zero (decided by implementation) .
>
> So in kernel , should we need register a undef hook to Get this
> undef exception and send SIGFPE to user space Process ?

As far as I can see, this can only happen for R-class cores, based on SCTLR.DZ.

Will
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