Re: [avr-libc-dev] 64-bit doubles

[Dave N6NZ]

Ron Kreymborg wrote:
> > -----Original Message-----
> > From: Weddington, Eric [mailto:address@hidden
> > Sent: Sunday, 21 December 2008 6:00 AM
> > To: Ron Kreymborg; address@hidden
> > Subject: RE: [avr-libc-dev] 64-bit doubles
> >
> >
> >
> > > -----Original Message-----
> > > From:
> > > address@hidden
> > > [mailto:address@hidden
> > > org] On Behalf Of Ron Kreymborg
> > > Sent: Saturday, December 20, 2008 5:03 AM
> > > To: address@hidden
> > > Subject: [avr-libc-dev] 64-bit doubles
> > >
> > > A quick look at AVR Libc for 20081205 still lists doubles as
> > > only 32-bit. Is
> > > this so? If yes does anyone know of a 64-bit double library?
> > > I am pointing
> > > heliostats and 32-bits are just not enough.
> > >
> > > Ron
> > Hi Ron,
> >
> > Yes, that is correct. Floats and doubles are 32-bits. No, I don't know
> > of a library. We (the avr-libc developers) have been advertising for
> > volunteers to help put together 64-bit double support for quite some
> > time. Nobody has volunteered yet.
> >
> > Eric Weddington
>
> Ok. For this project my good sense is saying go to a mcf52xx or M16C and a
> commercial compiler, but I have written fp code for now ancient processors
> and used the CORDIC transformations for transcendentals, so I'll have a look
> at AVRs over the xmas break. No promises...
>
> Ron
Is support for 64 bit double limited only by availability of a math 
library?  I would expect that 8-byte variables, register allocations, 
etc, would also be an issue, since avr-gcc doesn't have anything bigger 
than a 32-bit long or 32-bit float right now.

Isn't there some compiler infrastructure that would have to happen also?

-dave