The VAX 9000 does branch prediction & speculative fetches; kills,
aborts, and register logs made for debugging fun. "A cache cycle wasted
is lost forever" met "waste not, want not". It fetches aggressively.
It has multiple microcodes - some loadable, other compiled (and
optimized) into gates.
Paul - be careful. All CPU's post the IBM AGS that used branch prediction
are suspect. Russ Robelen (who was the 360/50 lead, worked on 360/90 and
lead AGS) has the speculative executing patent. I tweaked him when it all
came out and said - look at what you did.
What Russ and team are great
It might be worth asking on comp.os.vms as well, it’s one of the few USENET
groups that seems to still be active.
Zane
> On Sep 17, 2019, at 6:55 AM, Paul Koning wrote:
>
> "Spectre" is one of two notorious bugs of modern CPUs involving speculative
> execution. I rather doubt that VAX is
"Spectre" is one of two notorious bugs of modern CPUs involving speculative
execution. I rather doubt that VAX is affected by this but I suspect others
here have a lot more knowledge.
paul
> Begin forwarded message:
>
> From: co...@sdf.org
> Subject: VAX + Spectre
> Date: September
