On 11.12.2011, at 20:48, Peter Maydell <peter.mayd...@linaro.org> wrote:
> On 11 December 2011 19:30, Christoffer Dall > <c.d...@virtualopensystems.com> wrote: >> On Sun, Dec 11, 2011 at 11:03 AM, Peter Maydell >> <peter.mayd...@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 :-) Yes, the general rule of thumb is to use bit operations where you can. And in this case it certainly makes sense :). Plus, bit operations are an order of magnitude faster than div/mod usually. Alex -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
