[Qemu-devel] QEMU x86_64: problems with floats

[Ludovic Drolez <ldrolez@linbox.com>]

Hi !

I've found a bug in Qemu FPU emulation: conversion of floats to strings fails
in some cases. For example, Ganglia (cluster monitoring software), shows
random values. If I add debug in gmond, I get this:

VALUE =2.G= =2.343750=
VALUE =2.G= =2.343750=
VALUE =9Ö= =93.487236=
VALUE =0.6o= =0.640000=
VALUE =0.1;= =0.119600=
VALUE =0.00= =0.000311=
VALUE =0.0= =0.000000=
VALUE =0.0= =0.000000=
VALUE =9.ê= =95.312500=
VALUE =0.9= =0.940000=
VALUE =0.4Y= =0.420000=
VALUE =0.1;= =0.113054=
VALUE =0.00= =0.000536=

On the left the float is converted with apr_sprintf, and on the right with
printf. Also, floating point operations in PHP also fail...

I tested with Qemu 0.8.2 and today's CVS. Of course, it works with a real
system (the disk image was then installed on a PE1950).

Any ideas ?


-- 
Ludovic DROLEZ                              Linbox / Free&ALter Soft
www.linbox.com www.linbox.org