From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoffer Dall <christofferdall@christofferdall.dk>
Subject: Re: [Android-virt] [PATCH v5 05/13] ARM: KVM: Inject IRQs and FIQs
 from userspace
Date: Sun, 11 Dec 2011 15:07:06 -0500
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To: Peter Maydell <peter.maydell@linaro.org>
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On Dec 11, 2011, at 2:48 PM, Peter Maydell <peter.maydell@linaro.org> wrote:

> On 11 December 2011 19:30, Christoffer Dall
> <c.dall@virtualopensystems.com> wrote:
>> On Sun, Dec 11, 2011 at 11:03 AM, Peter Maydell
>> <peter.maydell@linaro.org> wrote:
>>> Removing the mask would be wrong since the irq field here
>>> is encoding both cpu number and irq-vs-fiq. The default is
>>> just an unreachable condition. (Why are we using % here
>>> rather than the obvious bit operation, incidentally?)
>>>
>> right, I will remove the default case.
>>
>> I highly doubt that the difference in using a bitop will be measurably
>> more efficient, but if you feel strongly about it, I can change it to
>> a shift and bitwise and, which I assume is what you mean by the
>> obvious bit operation? I think my CS background speaks for using %,
>> but whatever.
>
> Certainly the compiler ought to be able to figure out the
> two are the same thing; I just think "irq & 1" is more readable
> than "irq % 2" (because it's being clear that it's treating the
> variable as a pile of bits rather than an integer). This is
> bikeshedding rather, though, and style issues in kernel code
> are a matter for the kernel folk. So you can ignore me :-)
>
Well, if it was just "irq & 1", then I hear you, but it would be "(irq
>> cpu_idx) & 1" which I don't think is more clear.

But yes let's see what the kernel folks say.