Re: [Xen-devel] [PATCH RFC 04/25] Replace "/" operand with div64

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Wed, 7 Dec 2011, Keir Fraser wrote:
> On 07/12/2011 12:23, "Stefano Stabellini" <stefano.stabellini@xxxxxxxxxxxxx>
> wrote:
> 
> > On Wed, 7 Dec 2011, Zhang, Xiantao wrote:
> >> Hi, Stefano 
> >> Great work from you guys!  One quick comment:  Just found the below logic's
> >> change maybe wrong and probably  break current things.
> >> Original logic is  A+B -(C%D), but it is changed to  (A+B-C)%D,  so if it 
> >> is
> >> not an intended fix, it should be an issue.
> >> Thanks!
> >> Xiantao  
> > 
> > True! Thanks for spotting this!
> 
> For the avoidance of doubt: this patch 04/25 is wrongheaded, and I will nack
> it if it appears in the final patch series. You probably got this impression
> from me already. ;-)

Yes, I got it :)
I think that the right thing to do is removing this patch and
implementing __aeabi_ldivmod and __aeabi_uldivmod in assembly for ARM,
that would give gcc everything it needs to compile "/".
I have got a simple implementation based on __qdivrem and seems to work
OK.

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