-msse producing sse2 instructions

Dylan Cuthbert dylan@q-games.com
Mon Jul 22 01:30:00 GMT 2002


Hi all,

I managed to whittle it down to the place where the instruction is being
generated.. and the resulting executable produces an Illegal Instruction if
run on Athlon 4 machines, but not on Athlon MP/XP or Pentium 4s.

The line to compile with:

$>
g++ -mcpu=pentium3 -march=pentium3 -msse -mfpmath=387 -mpreferred-stack-boun
dary=4 -fno-implement-inlines -Werror -Wall  -Dstdext=__gnu_cxx -O2 -mno-cyg
win -mwin32  test.cpp -o test.exe

Compiling with -march=athlon-4 -mcpu=athlon-4 also causes the same code to
be generated.

On another note, I also get an illegal instruction error on this:

movss  0xfffffffc(%ebp),%xmm0

Seems to be in the integer->float conversion code tho. so I hope this helps.

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: Monday, July 22, 2002 1:43 AM
Subject: Re: -msse producing sse2 instructions


> "Dylan Cuthbert" <dylan@q-games.com> writes:
>
> > 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.
>
> Not necessarily different versions of an Athlon, but different
> environments.
>
> But without an example programs we cannot do any further investigation
> and any discussion is mood.
>
> Andreas
> --
>  Andreas Jaeger
>   SuSE Labs aj@suse.de
>    private aj@arthur.inka.de
>     http://www.suse.de/~aj
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