Re: Does anyone have a netbsd-5 or earlier VAX to hand?

[Mouse <mouse%Rodents-Montreal.ORG@localhost>]

>> Would it make sense to re-code that to use poly[df] instructions on
>> machines that have them?  Would the run-time check be more trouble
>> (or cycles) than it's worth?

> I think the sane way is to actually just use poly[fd] all the time,
> and let the emulation handle it if the machine don't actually
> implement it in hardware.

> No need for explicit checks, it's done automatically by the hardware.

(a) Is that true of all hardware which doesn't have direct POLY
support?

(b) Even if it is, do we want to do that?

(b1) I would expect the trap overhead to be significant.

(b2) I have seen it said that many of the more complex instructions
are, on many implementations, actually slower than doing the same thing
with multiple instructions.  POLY is a typical example.  I don't know
how true this is, but if it is true on a significant fraction of the
VAXen we care about then we might want to go with the open-coded
version instead of using POLY.

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