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

[Preston Wilson]

"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
>>> 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...

There is a fixed point library at http://sourceforge.net/projects/avrfix/
that may do what you need, or may be more easily extended to do what you
need.  It is worth a look.  That library has the trig functions (using
CORDIC transformations), sqrt, +, -, *, /, and possibly other functions.  I
have only looked at the library and not used it, and that was just over a
year ago when it was mentioned on either this or the avr-chat list.  The
library is licensed under LGPL, which may or may not be an issue for your
project.

If you are considering a commercial compiler, ImageCraft and IAR both
support 64-bit floating point on the AVR parts.

-Preston