Author christian.heimes
Recipients christian.heimes, gvanrossum, nascheme, noam, rhettinger, tim.peters
Date 2007-12-11.18:46:52
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Guido van Rossum wrote:
> No, traditionally Python has just used whatever C's double provides.
> 
> There are some places that benefit from IEEE 754, but few that require
> it (dunno about optional extension modules).

I asked Thomas Wouter about IEEE 754:
"""
I don't know of any system with FPU that does not support 754 semantics.
and all intel CPUs since the 486 have FPUs.
"""

During the discussion we found only one system that has supported Python
in the past but doesn't have IEEE 754 doubles. Pippy (Python for PalmOS)
has no floats at all since the hardware doesn't haven a FPU.

> So far I have only one box where it is broken (even after make clobber
> and ./configure). I cannot reproduce it with a debug build.
> 
> It's an x86 Linux box running in mixed 64-32 bit mode.
> 
> From /etc/lsb-release: "Ubuntu 6.06 LTS"
> uname -a: Linux pythonic.corp.google.com 2.6.18.5-gg16-mixed64-32 #1
> SMP Wed Oct 10 17:45:08 PDT 2007 x86_64 GNU/Linux
> gcc -v: gcc version 4.0.3 (Ubuntu 4.0.3-1ubuntu5)
> 
> I'm afraid I'll have to debug this myself, but not today.

The problem could either be related to SMP or to the mixed mode. Please
try to bind the Python process to one CPU with schedtool or schedutils.

> Only for IEEE 754 though.
> Of course the latter isn't guaranteed to help for non-IEEE-754
> platforms -- some platforms don't have NaNs at all!

Do you know of any system that supports Python and floats but doesn't
have IEEE 753 semantics? I'm asking out of curiosity.

Christian
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2007-12-11 18:46:53christian.heimessetspambayes_score: 0.00144623 -> 0.00144623
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2007-12-11 18:46:52christian.heimescreate