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Re: [RESUME] fpu emulator

To: "Kevin D. Kissell" <>
Subject: Re: [RESUME] fpu emulator
From: Andreas Jaeger <>
Date: 08 Feb 2001 13:06:29 +0100
Cc: "Florian Lohoff" <>, <>
In-reply-to: <005d01c091c4$69940620$0deca8c0@Ulysses> ("Kevin D. Kissell"'s message of "Thu, 8 Feb 2001 12:43:30 +0100")
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"Kevin D. Kissell" <> writes:

> > Hi,
> > just to get it right - As i thought the FPU emulator is not really
> > optional - It is even required for fpu-enabled devices which means
> > we should clean the code in that way that if the user decides to 
> > compile in the fpu emulator into the kernel we do an autodetection 
> > upfront and change some of the entry/exit/lazy_fpu stuff.
> > If the user decides not to compile in the FPU Emulator he is on his
> > own and we ignore the whole FPU stuff and simply send SIGILL/SIGFPE
> > to the processes causing all fpu binarys to fail on non-fpu enabled
> > kernels.
> Not quite.  Unless we create a variant of glibc that neither
> initializes the FP control register on program startup, nor

glibc doesn't initialize it for shared programs.

> saves/restores the FP registers in setjmp/longjmp, the

Any ideas how this can be done?

> model of "simply sending SIGILL/SIGFPE" will result
> in *all* processes being terminated with extreme prejudice,
> starting with init!

 Andreas Jaeger
  SuSE Labs

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