[issue18062] m68k FPU precision issue

[mirabilos]

mirabilos added the comment:

Laurent Vivier dixit:

> BTW, the result on a real CPU (68040) is :

68881 even ;-)

> test#1 fail: 1.00000000000000000E+00
> test#2 fail: 1.00000000000000040E+16
> changing FPU control word from 00000000 to 00000080 => 00000080
> test#1 good: 1.00000000000000022E+00
> test#2 good: 1.00000000000000020E+16

Thanks, that’s what I was guessing. I get similar results on i386.

Now as additional data point, UAE/WinUAE/etc. would be interesting.

Even so, I’d be very reluctant to add this code to Python to make
it change the FPU mode, because Python is heavily used in Debian,
and getting varying results between emulation and bare metal is
something we’d like to not have…

bye,
//mirabilos
-- 
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                                         -- Henry Nelson, March 1999

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