🚀 go-pugleaf

[Spencer]
# Well, "fully" if you discount the mishmash of four or five different
# floating-point formats, not all of which exist on all VAXen last I heard...

There have been rules for subsetting Vaxen since before there were Vaxen.
(I know because I just went looking for "trap type 9" and I ran across a
prehistoric version of the Vax Arch Ref Man in the DECWRL library).

Some implementations leave out some floating point types; others leave out the
POLY and EDITPC and sometimes MOVC.  These you do in software; if the hardware
can do it (either by basic design or because of an accelerator), you don't see
the traps and your code runs faster.

I'll admit, it's not the way I'd design something today.  But in 1970, they
had some design ideas that they couldn't implement in hardware "yet", and
some other ideas that they knew would be hard to put into a low-end model
later on.  Looking back at it, it seems like they did okay.
--
Paul Vixie
Work:    vixie@decwrl.dec.com    decwrl!vixie    +1 415 853 6600
Play:    paul@vixie.sf.ca.us     vixie!paul      +1 415 864 7013