Re: [rtl] math emulation ?

[Paolo Mantegazza <mantegazza@aero.polimi.it>]

Michael Barabanov wrote:
> 
> Wolfgang Guldner (w.guldner@bfad.de) wrote:
> > Hello everybody,
> >
> > I installed rtlinux2.0 on a 486 AMD SC410 without FPU, so I turned on
> > the CONFIG_MATH_EMULATION  in the Kernel.
> > Everything works fine until I try to start the fp example. Then the System
> > crashs with the following message:
> >
> > math_emulate: 0010:c1823aa9
> > Kernel panic: Math emulation needed in kernel
> >
> > What can I do?
> 
> Right now, you can't use RT-threads that use FP on CPUs without an FPU.
> You can help with making RTLinux use the Linux FP emulator code.
> 
> Michael.

I like to recall to you all that at the RTL site there is already
something in that direction. Moreover also Daniele Danlugli did
something about FPU emulation, 3 years ago.

Beside that remember that a today scarce PC will cost about 500 $, and
outperform any fp emulation on an old 486. If you are able to code a
fully featured FP emulation, or to port that available in Linux, you are
a programmer worth 40 $/h work. That means that after three nights of
overwork you are loosing money :-). Better to go to a PC dump site and
buy and old Pentium for 50-100 $.

Ciao, Paolo.