Re: Re: Floating Point using AN974 with MC9S12A256

>
>
> --- In 68HC12@... <mailto:68HC12%40yahoogroups.com>,
> "ga5941" <ga5941@...> wrote:
> >
> > --- In 68HC12@... <mailto:68HC12%40yahoogroups.com>,
> David Armstrong <mamoru.tbreesama@> wrote:
> > >
> > > If you have a working version of the AN974 Floating point code,
> why not
> > > share it with the rest of the community here? I'm sure there are
> several
> > > individuals that would like to see and use it.
> > >
> > > Dave
> > >
> > > On Thu, Apr 30, 2009 at 4:48 PM, ga5941 <ga5941@> wrote:
> > >
> > > >
> > > >
> > > > Earlier I reported a problem(16296)using AN974, MC68HC11
> Floating Point
> > > > Package by Gordon Doughman. I'm now happy to report that I have
> resolved the
> > > > problem and it wasn't with AN974. My floating point calculations
> in assembly
> > > > code are working correctly including trig functions. The
> package, however,
> > > > does not include an Arctan function. I have written my own, in
> assembly of
> > > > course, using the Cordic algorithm. The Arctan function is
> necessary for
> > > > converting celestial coordinates RA and DEC to earth based
> coordinates ALT
> > > > and AZ.
> > > >
> > > > A reply to my original note suggested a possible difference
> between HC11
> > > > and HC12 regarding stack operations but I have found none when
> using AN974.
> > > >
> > > > Thanks to all that replied.
> > > >
> > > >
> > > >
> > >
> > >
> > > [Non-text portions of this message have been removed]
> > >
> > After extensive search of Freescale files, I found the AN974/D
> document. It is type .pdf, 745 KB. You can download it from:
> >
> >
> http://www.freescale.com/files/microcontrollers/doc/app_note/AN974.pdf?fpsp=1&WT_TYPE=Application%20Notes&WT_VENDOR=FREESCALE&WT_FILE_FORMAT=pdf&WT_ASSET=Documentation 
> <http://www.freescale.com/files/microcontrollers/doc/app_note/AN974.pdf?fpsp=1&WT_TYPE=Application%20Notes&WT_VENDOR=FREESCALE&WT_FILE_FORMAT=pdf&WT_ASSET=Documentation>
> >
> > It was located with the application notes for the MC68HC11 micros. I
> did not find the actual software file itself though it is listed in
> the AN974/D document. The actual code file is about 2 KB. I do not
> have my own website but can send it in an e-mail as a file attachment
> to someone who maintains a website. Any volunteers?
> >
> > The routine for Arctan(X) that I wrote in assembly code also
> includes Arcsin(X) and Arccos(X) and runs 249 bytes. To obtain a
> proper understanding of it one should also read this paper:
> >
> > http://www.andraka.com/files/crdcsrvy.pdf 
> <http://www.andraka.com/files/crdcsrvy.pdf>
> >
> > and another that I downloaded from the internet but is no longer
> accessible. This one runs about 48 Kb.
> >
> > I would be happy to help anyone who needs this material. Perhaps it
> could be done through this 68HC12 Yahoo group through the file system.
> > I don't know how to use the file system, perhaps someone could walk
> me through it. My email addr is ga5941@...
> >
> > Gil
> >
> I've found the URL for this last paper; it is the most important for
> understanding how to implement the Cordic algorithm for the Arctan
> function:
>
> http://www.restena.lu/convict/Jeunes/Math/arctan.htm 
> <http://www.restena.lu/convict/Jeunes/Math/arctan.htm>
>
> Gil
>
>