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    SubjectRe: floating point exception
    "Richard B. Johnson" wrote:
    >
    > On 16 Jan 2002, Christian Thalinger wrote:
    >
    > > On Wed, 2002-01-16 at 15:32, Zwane Mwaikambo wrote:
    > > > Can you also reproduce _without_ loading NVdriver, just to make everybody
    > > > happy.
    > > >
    > > > Thanks,
    > > > Zwane Mwaikambo
    > > >
    > >
    > > Sure, same breakdown. Maybe it's really an dual athlon xp issue as dave
    > > jones mentioned. But shouldn't this also occur when i trigger a floating
    > > point exception myself? Is there a way to check which floating point
    > > exception was raised by the seti client?
    > >
    > > Regards.
    > >
    >
    > Maybe you can run it off from gdb? Or `strace` it to a file? Usually
    > these things are caused by invalid 'C' runtime libraries, either
    > corrupt, "installed by just making a sim-link to something that
    > was presumed to be close to what the application was compiled with",
    > or an error in mem-mapping.
    >
    > Another very-real possibility is that somebody used floating-point
    > within the kernel thus corrupting the `seti` FPU state. You can
    > check this out by making a program that does lots of FP calculations,
    > perhaps the sine of a large number of values. You put the results
    > into one array. Then you do the exact same thing with the results
    > put into another array. Then just `memcmp` the arrays! You run
    > this in a loop for an hour. If the kernel is mucking with your FPU,
    > it will certainly show.

    Hmm, that's an interesting idea... An Athlon optimised kernel does use
    the MMX/FPU registers to do mem copies. Try running a kernel compiled
    for just a Pentium and see if the problem persists.

    --

    Brian Gerst
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