I may be missing something but the Appendix (A&B) of Microchip AN660 claims
to have floating point code for both the 17C and the 16C both with the POW24
and POW32 routines. I can't comment on how good either of these routines are
but after much research they are the only ones I have found.

I plan on attempting to convert the 17C code  for use on the 18F452 soon. I
hope I'm not biting of more than I can chew.

(New to the list)
Mike Jones

----- Original Message -----
From: <jmartin@COMP.UFSCAR.BR>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Thursday, January 09, 2003 7:01 AM
Subject: Re: Floating Point Math Routine (Pow) for PIC16


> Scott:
>
> p1 and p ranges: 100.000 hPa to 1200.000 hPa
>
> ok ??
>
> Tanks!!
>
> []4s
> Jeferson Martin
>
> Scott Dattalo <scott@DATTALO.COM> escreveu:
>
> > On Thu, 9 Jan 2003 jmartin@COMP.UFSCAR.BR wrote:
> >
> > > Scott, i4m trying to do an altimeter based on pressure altitude.
> > >
> > > So, the eq is:
> > >
> > > H = 44330,769[1 - (P/P1)^0,190255]
> > > Where H is the altitude, P is the air pressure at altitude H at
> > > a given and variable sea level pressure P1.
> >
> > That doesn't answer the question. Again, what are dynamic ranges of P
and
> > P1? Do these come from an 8-bit A/D converter or what? You originally
> > asked for 32-bit precision, but I doubt you need it.
> >
> > It'd probably make sense in a PIC to re-write this equation like:
> >
> > H = A * ( 1 + P^B * (1/P1)^B)
> >
> > Use a lookup table to compute f(x) = x^B and then perform the simple
> > arithmetic computation that follows. Of course, you'll need to scale the
> > 1/P1 in a range suitable for the table. But I can't tell what the scale
> > factors should be without first knowing the dynamic range of your
> > variables.
> >
> > Scott
> >
> > --
> > http://www.piclist.com hint: The PICList is archived three different
> > ways.  See http://www.piclist.com/#archives for details.
> >
>
>
>
> --
>
> --
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