Aha! TY. Sun's floating point people were world class but I still think this was a dumb thing to do.
With the NAS Parallel Benchmarks we were trying to encourage as wide a diversity of hardware and algorithms as possible so we were lenient with the acceptable "valid" interval of "correct" behavior. I've already discussed heretical Cray FP. Those were fantastic systems. No way would we disqualify some weird/different algorithm/architecture if it meaningfully advanced the SOA in performance/efficiency. OTOH wars were fought over having any firm accuracy requirements at all. So this jvm thing looked... pointless at best?
This is all nostalgia for a past that actually was. Those were the days my friends.
> this was a dumb thing to do.
Spoken like someone who never had to implement multi precision library. Thankfully Sun's idea won, the 80bit shape shifting to 64 bit upon register spill is a distant past, all modern processors implement fully deterministic +-*/ float64 ops, which allows sane and portable libraries for quadfloats, multi precision, interval arithmetic and the like
Ah. So now we are talking about multi-precision libraries, which their basic reason for existing is that different precision formats yield different economically interesting results, via a variety of a not-large set of economically interesting tradeoffs.
The 80 bit format was an at-the-time (ATT) engineering optimization that made ATT double precision (DP) more attractive given the better round-off behavior, at "no-cost".
So the interesting question here (that I don't know) is: is "deterministic" quad-precision (QP) as the accuracy upgrade from "non-deterministic" 80bit internal DP, always better economically?
Depends on what the computational problem is, given a budget. And that budget buys things that are only available on the market.
I used to think technology monocultures were a good thing but given the current state of things I have reversed myself. I am happy that life has simplified for you though.
I've been watching, lightly, interval arithmetic for 40 years. As you know algorithm sensitivity information is mandatory. We used intel 80bit FP do evaluate that, slowly, back in the day. We didn't use interval arithmetic, though we knew about it. It wasn't economically viable. Hey C++ what can you do for us? Templates, damn.
How important is interval arithmetic, economically, now?