SIGFPE trapping on HPPA (was: Yorick FTBFS: DM needs access to HPPA machine)

[Thibaut Paumard <mlotpot.news@free.fr>]

> [1] http://packages.debian.org/sid/yorick
> [2] http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=559406

Hello,

Thanks to access to Frans I have been able to test a little bit more  
this issue.

It turns out the Yorick code is able to trap SIGFPE when it is  
triggered by an integer division (1/0) but not when it is triggered by  
a floating point division (1./0.).

In the former case, Yorick correctly signals the exception to the user  
with a Yorick error message and stops to wait for input, whereas in  
the latter it just dies with the single line "Floating point exception".

Under some circumstances (when and integer SIGFPE has been raised  
previously), I have been able to have my handler output a short  
message, but then it loops (this short message is repeated  
indefinitely). Calling feclearexcepts() before outputting this message  
did not help: when attempting a floating-point division by zero,  
either yorick dies or the handler loops. The first three lines of the  
handler on this test case are:
  feclearexcept(FE_ALL_EXCEPT);
  printf("in u_sigfpe\n");
  fflush(stdout);

The handler is setup using signal(2):
  signal(SIGFPE, &u_sigfpe)

HPPA is the only architecture so far which exhibits this behaviour.

Does anyone has an idea of what I could do to fix this? Is there  
something specific in the way HPPA handles SIGFPE trapping? Why is it  
different between integer SIGFPE and floating SIGFPE?

Best regards, Thibaut.