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Message
From: "Damjan Lampret" <lampret@o...>
Date: Thu, 11 Sep 2003 15:18:37 +0200
Subject: Re: [openrisc] SIGBUS when using eCos diag_printf
In another project there was also a strange thing going on and it turned out
to be the stack overrun. Setting the stack to be bigger immediately solved
the problem. I don't know if this is the same in your case.
regards,
Damjan
----- Original Message -----
From: <rcc@j...>
To: <openrisc@o...>
Sent: Thursday, September 11, 2003 9:50 AM
Subject: Re: [openrisc] SIGBUS when using eCos diag_printf
> Hi Marko,
>
> This occurs when using -O2 optimisation flag, but doesn't occur if I
> don't specify optimisation (i.e. no -O flag at all), so I have solved the
> immediate problem but it does make the code considerably larger :-(
>
> Initial inspection seems to suggest that either the stack is getting
> corrupted or register misuse is occurring in the optimised code, as the
> exception occurs shortly after returning from the modulo call and
> appears to be due to dereferencing a bad address in a register:
>
> 820c: 04 00 0a 16 l.jal aa64 <___umoddi3>
> 8210: d7 e2 97 a4 l.sw 0xffffffa4(r2),r18
> 8214: 84 d2 00 04 l.lwz r6,0x4(r18)
>
> In the above, r18 has a bad address in. The unoptimised version looks
> like this, i.e. no instruction in the delay slot.
>
> 1410: 04 00 25 95 l.jal aa64 <___umoddi3>
> 1414: 15 00 00 00 l.nop 0x0
> 1418: 84 ab 00 00 l.lwz r5,0x0(r11)
>
> It would be nice to get to the bottom of why this occurs; if I have some
> spare time (I wish) I will try to unravel it a bit more.
>
> Robert
>
> ----- Original Message -----
> From: Marko Mlinar <markom@o... >
> To: openrisc@o...
> Date: Thu, 11 Sep 2003 08:09:19 +0200
> Subject: Re: [openrisc] SIGBUS when using eCos diag_printf
>
> >
> >
> > Robert,
> >
> > my guess would be that pointers for string decoding in libc are not
> > set-up
> > correctly or get messed-up. Usually libc libraries detect whether
> > your string
> > has something to replace e.g. % characters, also usually it has
> > some last
> > used combination cached. If there is something to replace it
> > allocates new
> > string or uses some static (more often) space, where it works. I am
> > not
> > familiar with library you are using, so I unfortunately cannot be
> > more
> > specific.
> >
> > hope it helps anyway,
> >
> > Marko
> >
> > On Wednesday 10 September 2003 19:19, Robert Cragie wrote:
> > > This is a bit of a long shot posting here, but I was wondering
> > if anyone
> > > else has experienced this problem. I am getting a SIGBUS (bus
> > error)
> > > exception when trying to call the printf supplied with eCos.
> > This is
> > > generic code and works fine on all other eCos platforms, so
> > the problem
> > > must be something to do with the OpenRISC environment.
> > >
> > > If I do:
> > >
> > > diag_printf("Just a string\n");
> > >
> > > it seems to work OK.
> > >
> > > However, if I do:
> > >
> > > diag_printf("Print an integer %d\n", integer);
> > >
> > > it bombs out of GDB with something like this:
> > >
> > > Program received signal SIGBUS, Bus error.
> > > 0x00007f9c in _cvt(unsigned long long, char*, long, char*)
> > (val=1987,
> > > buf=0xcc0c "", radix=10, digits=0x1116c "0123456789")
> > > at
> > /home/rcc/ecos-sr/ecos/packages/infra/current/src/diag.cxx:273
> > > 273 *cp++ = digits[val % radix];
> > > Current language: auto; currently c++
> > >
> > > I am using GDB 5.3 and GCC 3.2.3 from the OpenCores CVS
> > server.
> > >
> > > Anyone seen this, or any ideas what might be going on? My
> > feeling is it's
> > > something to do with the 'val % radix' expression - 'val'
> > being unsigned
> > > long long etc and the associated math library. I will continue
> > to
> > > investigate further and see if I can spot anything odd.
> > >
> > > Robert Cragie, Design Engineer
> > >
> >
> _____________________________________________________________
> __
> > > Jennic Ltd, Furnival Street, Sheffield, S1 4QT, UK
> > > http://www.jennic.com Tel: +44 (0) 114 281 2655
> > >
> >
> _____________________________________________________________
> __
> >
>
>
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