[Tinyos-devel] external (nx*) types and floating point

[Vlado Handziski]

I think I lost you there. What do you understand under MCU specific
nx_float/nx_double definitions? How the serialization is implemented? Cause
the whole point of nx_* was to provide platform independent types, so the
"semantics" of the type should be the same all over, isn't it?

Vlado

On Fri, May 2, 2008 at 11:19 PM, David Gay <dgay42 at gmail.com> wrote:

> On Tue, Oct 9, 2007 at 9:07 AM, David Gay <dgay42 at gmail.com> wrote:
> > There's currently no nx_float / nx_double type that would allow use of
> >  floating point in protocols.
> >
> >  Two questions:
> >  - how necessary are such types? (w/o them, you have to figure out some
> >  integer encoding for any real numbers you have to deal with)
> >
> >  - does anybody have some portable code (and not too large...) for
> >  converting an array of bytes to a float/double? (that's the main
> >  sticking point as far as I'm concerned)
> >
> >  Some additional comments:
> >  - specifying these types as IEEE 32 and 64-bit numbers seems reasonable
> >
> >  - I'm reluctant to include platform-specific code w/ the nesC
> >  distribution to deal with nx_float/nx_double, as it feels like it
> >  would make nesC maintenance more painful
> >
> >  - we could actually  define nx_float/nx_double in TinyOS (on a
> >  per-chip or per-platform basis, e.g.) - external types are defined by
> >  a magic (undocumented) attribute, so can fairly easily be added
> >  independent of nesC
>
> Did anyone care about this? Offhand, it did seem worthwhile doing the
> last proposal (defining nx_float/nx_double for each MCU).
>
> David
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