Subject: Re: zs dropping chars
To: None <mouse@Collatz.McRCIM.McGill.EDU>
From: None <>
List: port-sun3
Date: 04/01/1996 16:16:56
der Mouse <mouse@Collatz.McRCIM.McGill.EDU> writes:

  >>> Well.  I am quite pleased.  It seems that something in the last few
  >>> weeks' changes to the sun3 kernel has fixed [...a zs driver bug...]

  >> I am not so happy unfortunately.  When I tried the new kernel bash
  >> stopped working.  [...]  Is there some sort of optional compatability
  >> support which has been left out?

This bash had been built under SunOs.

  > This sounds as though you are using someone's pre-built kernel....

  > And yeah, it does sound like a missing compatability option to me.

Well, I built my own kernel and found the same thing. It turns out that
the problem is that bash executes a "trap 2" instruction.
In the old locore.s, trap 2 did something (a "jra _trace" I think).
In the new locore.c it (deliberately) panics. I think the bash is 
dynamically linked and that the "trap 2" arises from some code which
is associated with the dynamic linking. Does anyone know what
"trap 2" was meant to do under SunOS? Maybe it was some sort of
cache flushing thing.

Putting the old code back into locore.s makes bash work, but I suspect
it is not *right*.