On 9/19/00 at 12:36, hotz@jpl.nasa.gov (Henry B. Hotz) wrote:

> At 6:47 PM +0100 9/19/00, Phillip R Arrieta wrote:
> >Hi, I just have a quick question
> >
> >I was wondering if NetBSD will do useful things on my LC040 box 
> >(PowerBook 540c). The doc on this subject
> >(http://www.macbsd.com/macbsd/LC040-and-BSD.html) left me a little 
> >confused at the end. I've installed SoftwareFPU, and I am able to 
> >run Fractal! v1.2 w/o any problems.
> >
> >Does this mean that I will be able to useful things w/o
> >getting "Seg faults" and others?
> 
> I think this means that your version of the chip is not
> defective. However the last I heard we still did not have a
> good FP emulator for the '040.  In other words you should be
> able to do some stuff, but you won't have a fully functional
> system.
> 
> Is Ken Nakata still on the list?  He was the last person working on 
> the emulator that I know of.
> 

The above web page also suggests that Allen Briggs was going to work
on the FPU emulator problems on the LC040. That page is dated 1997. It
would be great if we could update it with the current state of things,
if only to say that nothing has changed. Some of the links are stale,
too.

I too have an LC040 box (Performa 475) that seems to work fine with
Software FPU. I successfully booted NetBSD 1.4.2 into single user mode
but some of the simple commands I tried resulted in seg faults. The
shell continued to run which surprised me. I was expecting the system
to crash thinking that the FPU emulator was in the kernel. Perhaps the
stack is getting corrupted by the emulator and so only that process
fails.
I'm interested in investigating how the emulator works and the
problems with it. Any information would be appreciated: pointers to
documentation, where the NetBSD FPE code resides, how the FPE works,
theories about what's going wrong with FPE on the LC040, etc.