Re: [B2-devel] Re: New SIGSEGV code to be committed

[Gwenole B. <gb...@di...>]

On Wed, 18 Jul 2001, Brian Johnson wrote:

> Here's what I got on a recent CVS build.  Using 68030+FPU, direct
> addressing, I started up the calculator and entered 4 / 3.  When I
> typed the 3, B2 core dumped with a SIGBUS:

OK, thank you for the report, I will try to investigate but don't expect
it to be soon, unfortunately. I will have plenty of work untill October,
at least...

Anyway, if this can reassure you, I also get FPU emulation problems on
ia64. Results are totally wrong and the following shows up in
/var/log/messages:

Aug 19 15:24:41 lion kernel: BasiliskII(3200): floating-point assist fault
at ip 40000000000d71f1
Aug 19 15:24:41 lion kernel: BasiliskII(3200): floating-point assist fault
at ip 40000000000cf141
Aug 19 15:24:59 lion kernel: BasiliskII(3200): floating-point assist fault
at ip 2000000000280bd1
Aug 19 15:24:59 lion kernel: BasiliskII(3200): floating-point assist fault
at ip 2000000000280bf1
[...]

What the hell is an "floating-point assist fault" ? Software/kernel
emulation of some FPU instructions ?

> > Could you tell me the address reported by the segv handler and the
> > MEMBaseDiff offset value ?
>
> I'm having trouble tracking it down...   perhaps it got optimized
> away.

In main_unix.cpp, around line 351, you can put a printf() for MEMBaseDiff.
Anyway, in Direct Addressing, MEMBaseDiff == RAMBaseHost so if DEBUG is
set to 1, the D(bug(...)) will trigger it.