On Thu, 6 Apr 2000, Gregg Lobdell 234-0884 wrote:

> I am looking for a PIC (16F84 or similar) assembler routine to compute
> arcsin with 32 bit floating point numbers.  Routines using lookup
> tables and interpolation need not apply, this needs to be accurate.
> Alternately, a good arctan routine would be acceptable, but I do need
> arcsin for this application and so I would have to compute an extra
> square root, which I'd like to avoid.  I thought I found an arctan
> routine on the web, but now I can't locate the link.
>
> Failing an implemented routine, a well described algorithm would be
> acceptable.  I already have the power (McLauren, Taylor) series
> expansion algorithms for both asin and atan.  In my application, the
> angles will be between 0-30 degrees; a range where the power series
> converge relatively quickly.  If I'm going to implement something from
> scratch though, I'd like to use an algorithm that converges well over
> the complete range of the function, so it is more general. So, any
> math majors out there?



Since you've ruled out look up tables, then I won't bother refering you to my
web pages where there are solutions for sine, arcsine, arctan and sqrt. Instead
I'll ask why do you need 32 bit floating point results for something controlled
by a pic? What's your application?


Scott