Path: utzoo!utgpu!watmath!clyde!att!rutgers!deimos!uxc!uxc.cso.uiuc.edu!mcdurb!aglew
From: aglew@mcdurb.Urbana.Gould.COM
Newsgroups: comp.arch
Subject: Re: Quadruple-Precision Floating Point
Message-ID: <28200255@mcdurb>
Date: 5 Jan 89 00:49:00 GMT
References: <8561@alice.UUCP>
Lines: 23
Nf-ID: #R:alice.UUCP:8561:mcdurb:28200255:000:1124
Nf-From: mcdurb.Urbana.Gould.COM!aglew    Jan  4 18:49:00 1989


>We did a weird thing :-) at MIPS with these instructions.  Whenever one
>of these instructions is encountered, the trap handler emulates the
>instruction, AND it does something else.  :-)   It instructs the console
>maintenance processor to activate its remote-diagnostics modem, which
>dials a special phone number back at the factory, here at MIPS.  In fact
>it dials a phone which sits on my desk :-).  The maintenance processor
>logs the date and time, the serial number of the machine, and the type of
>longer-precision operation that was requested :-).
>
>So far, in over 2 years, the phone has never rung.  :-)  Thus it is
>tempting to conclude that user programs do not suffer a serious
>performance degradation from emulating longer-precision (80 and 128 bit)
>floating point operations in software :-).
> 
> -- Mark Johnson	

What a beautiful story! I love it!

But, one question: are remote diagnostic modems optional on MIPS systems?
They're optional on most of the computer systems I've used (anonymous
68K boxes, Goulds, Motorola VME systems) and I've never yet worked on
a system that exercised that option.