Axiom that lets you play stereo sound.

CalcNet and gCn Axioms would be super-fantastic.

And they aren't very hard, either. It's just a few subroutines and a few memory addresses. I could probably write one in my spare time. And gCn uses the same commands as CALCnet.

Axiom that supports USB sound.

Or USB input (like a mouse or flash drive).

a gCn Axiom will definitively be really great.

How about some more advanced string operations?

There are a few Axe-made subroutines good enough for the job.

I guess... Why use ASM, which is harder to deal with strings than Axe to help Axe dealing with strings?

For accurate trig functions you'll pretty much have to turn to a LUT. The only reason sine and cosine routines exist is because they have a limited range and can be somewhat accurately approximated by a quadratic function. And by somewhat accurate, I mean errors reaching 10%. Trying to model just about any other trigonometric function with a simple model would probably result in wild amounts of error, and trying to model them with a more complex model would probably end up being larger than a LUT-based solution anyway. Unless you need a variable argument for your scale factor, it's best to just use a custom pre-computed LUT.

LUT = Look-Up Table. In this case a bunch of precalculated values for the trig functions to save on calculation speed and size.

Mouse and keyboard support.