Re: -msse producing sse2 instructions

[Jan Hubicka <jh at suse dot cz>]

> 
> Hello there,
> 
> Well, I run the same executable on an Athlon MP with no problem.  When I run
> on an Athlon 4 gdb tells me the program has crashed with an illegal
> instruction and displays that instruction I sent earlier.
> 
> However, as Tim Prince mentioned, it might be an alignment issue with
> different versions of the Athlon being more fussy about alignment than
> others and invalidly reporting the problem as an illegal instruction.

This does not happen.  The missaligned accesses are reported as
segmentation violation and additionally the instruction is scalar and
does not require any alignment.  I would bet to the BIOS or Windows
problem.  It is possible to verify whether SSE is enabled by cpuid
instruction that is available in Linux systems in /proc/cpuinfo but I am
not sure whether there is some equivalent for W.

Honza
> 
> Regards
> 
> ---------------------------------
> Q-Games, Dylan Cuthbert.
> http://www.q-games.com
> 
> ----- Original Message -----
> From: "Andreas Jaeger" <aj@suse.de>
> To: "Dylan Cuthbert" <dylan@q-games.com>
> Cc: <gcc@gcc.gnu.org>; "Jan Hubicka" <jh@suse.cz>
> Sent: Sunday, July 21, 2002 10:28 PM
> Subject: Re: -msse producing sse2 instructions
> 
> 
> > "Dylan Cuthbert" <dylan@q-games.com> writes:
> >
> > > Hello there, thanks for the quick response.
> > >
> > > Whilst I see if I can track down a small test program (it only occurs in
> the
> > > big unwieldy programs right now, as these things always seem to do)
> here's
> > > some extra info:
> > >
> > > I'm compiling currently
> > > with -mfpmath=387 -msse -mcpu=pentium3 -march=pentium3 and gcc 3.1.1-4
> from
> > > the very latest experimental cygwin distribution.
> >
> >
> > > One of the problems with tracking this down is my machine is an Athlon
> MP
> > > and has no trouble with SSE2 instructions, however a client's machine is
> an
> > > Athlon 4 and exhibits the problem.  And of course we need the SSE
> builtins
> > > for speed improvements. -_-;;
> >
> > Athlon 4s do not have SSE2, they're the same as Athlon MP (both have
> > SSE only).
> >
> > Btw. cvttss2si is an SSE instruction, not an SSE2 one AFAIK.
> > Therefore are you sure that you get an Illegal instruction for
> > cvttss2si?  Or is this some other error and you're just confused.
> >
> > Andreas
> > --
> >  Andreas Jaeger
> >   SuSE Labs aj@suse.de
> >    private aj@arthur.inka.de
> >     http://www.suse.de/~aj