On Tue, Feb 18, 2014 at 9:08 AM, Jakob Kummerow <[email protected]>wrote:
> On Tue, Feb 18, 2014 at 8:28 AM, <[email protected]> wrote: > >> Math.imul, Math.clz32, ... What will be next? :) > > > Math.f2xm1(), I think. > :-P * * * > > AFAICT "count leading zeroes" has HW support for all >> our platforms and boils down to a single CPU instruction, > > > It would be interesting to see how fast that single instruction is. If > it's implemented as a bit test loop in microcode, then rolling our own > (based on binary search + lookup table or something?) might be faster :-) > Then again, as long as there's no common use case where clz32 is the > bottleneck, this is of purely academic interest. > IIRC there was an article about using compiler intrinsics in one of the 2013 issues of either "c't" or "Linux Magazin", don't remember, but clz seems to be crucial for some real world programs and there was some significant speedup for some CPU models (<= that much I can remember ;-). -- -- v8-dev mailing list [email protected] http://groups.google.com/group/v8-dev --- You received this message because you are subscribed to the Google Groups "v8-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
