paper: CORDIC Trigonometric Math Library

[Pat Fairbank]

I just uploaded a second revision to the trig library. There was a bug in the way the previous versions were handling the C function calls in assembly - the software stack wasn't being manipulated properly, with the result that the trig functions would work as expected when called from a function that didn't have local variables, but would return strange values when called from a function that did.

So if you're using the library and are seeing strange return values, you probably have an older version and need to update to Revision 2.

[comphappy]

EDIT: Ignore this post, I can not delete it

[neutrino15]

What is the advantage to using this vs a lookup table to the desired degree of accuracy?

How much more accurate and slow is the built in <math.h>?

[Uberbots]

Originally Posted by neutrino15

What is the advantage to using this vs a lookup table to the desired degree of accuracy?

How much more accurate and slow is the built in <math.h>?

Well, the math.h implementation can be called ~100 times per second (speed test that was posted on CD at some point this month), and this function takes a half second for 4500 calls (a half second being the max time a loop can execute before the OI says it 'crashed')

so id say its about... 90x faster?

someone call me on this if my math is wrong.

[comphappy]

Ok i just found out what is needed to get this code to compile with the new 3.02 or higher compiler,
you need to replace all instances of AARGB3 with the new definition of __AARGB3
you can see the reference to this naming change here:
http://ww1.microchip.com/downloads/e...03-README.html
ref (27624)