On Fri, 2013-11-01 at 12:08 -0400, Neil Horman wrote: > On Fri, Nov 01, 2013 at 03:42:46PM +0000, Ben Hutchings wrote: > > On Thu, 2013-10-31 at 14:30 -0400, Neil Horman wrote: > > [...] > > > It > > > functions, but unfortunately the performance lost to the completely broken > > > branch prediction that this inflicts makes it a non starter: > > [...] > > > > Conditional branches are no good but conditional moves might be worth a > > shot. > > > > Ben. > > > How would you suggest replacing the jumps in this case? I agree it would be > faster here, but I'm not sure how I would implement an increment using a > single > conditional move.
You can't, but it lets you use additional registers as carry flags. Whether there are enough registers and enough parallelism to cancel out the extra additions required, I don't know. Ben. -- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
