A while ago I contacted Jukka Laurila from the Nokia developer board
about IEEE 754 support on S60 phones. The information from Jukka may be
useful for future reference.
Christian
-------- Original Message --------
Subject: Re: Python 2.6/3.0, IEEE 754 floating point semantics and S60
We've been battling with some float problems recently as well in the
course of our 2.5 core porting. The principal problem has been imprecise
floating point formatting/parsing routines which lead to the unfortunate
case of not being able to roundtrip a Python float to string and back
bit-exactly. I've been trying to get to the bottom of that problem and
so far it seems like the root cause is a poorly written C library.
Though on the other hand, no one from Symbian is yet to confirm to me
that the software-emulated floating point routines correspond to
anything like IEEE 754. Most S60 devices lack floating point hardware.
The best guess is that the floating point support is IEEE 754'ish, with
imprecise formatting and parsing routines in the standard library.
-Jukka
On 2.2.2008 3.54, "ext Crys @ Developer Discussion Boards"
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http://discussion.forum.nokia.com/forum/index.php ). The Developer Discussion
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This is the message:
Hallo jplauril!
I'm a Python core developer. Mikko Ohtamaa said that I should contact you
about this matter.
Mark Dickinson and I are working on several math and floating point related
enhancements for Python 2.6 and 3.0. The enhancements include better support
for IEEE754 style NaN and INF, C99 math functions and consistent errors and
return values across platforms.
Can you give use some detailed information about how Nokia's S60 series
processes and stores double precision floats? Information about Qtopia would
be useful as well.
See http://permalink.gmane.org/gmane.comp.python.devel/91591
Your's truly
Christian Heimes
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