Ethereal-dev: Re: [Ethereal-dev] Handling DOUBLES

Note: This archive is from the project's previous web site, ethereal.com. This list is no longer active.

From: Frank Singleton <frank.singleton@xxxxxxxxxxxx>
Date: Fri, 06 Apr 2001 06:58:42 -0500
Frank Singleton wrote:
> 
> Guy Harris wrote:
> >
> > > The proto_tree_add_item() function pulls the data from the tvbuff
> > > directly. That means that there has to be some universal
> > > double-precision floating point format that is used in protocols.
> > >
> > > There is for integers, but we have to specify big-endian or
> > > little-endian
> > > (that's the reason for the "little_endian" argument to
> > > proto_tree_add_item()).
> > >
> > > I'm not an expert in floating-point representations and how they're
> > > used on the wire for various protocols.
> >
> > There isn't any truly universal format...
> >
> > ...but, at this point, most modern protocols that shove floating-point
> > numbers over the wire in a standard format (rather than the native
> > format) probably do so in IEEE format.
> 
> <snip>
> 
> Hi,
> 
> Yes we need IEEE 754-1985 for dissection of floating
> point types such as float, double and long double
> in our CORBA stuff also.
> 
> I think I have some docs on this, so I will have a
> crack at it.
> 

IEEE 754-1985 Floating point numbers ....

    float  - 4 bytes
    double - 8 bytes
    long double - 16 bytes

 
/Frank

-- 
EUS/SV/Z Frank Singleton      ASO Americas BSS
Office : +1 972 583 3251      ECN 800 33251  
Pager  : +1 800 651 1184      Mobile : +1 214 228 0874
Amateur Radio: VK3FCS/KM5WS   Email : frank.singleton@xxxxxxxxxxxx

Hardware: HP Omnibook 4150 running Redhat Linux 6.2 (2.2.16 kernel).