I do not know J2ME well enough to know, but you have Math.log()and Math.exp()?
Then you can just use this relation:
x^y = exp(y * log(x))
If you do not have the above two functions, you should start by implementing them. As far as I know, the above relation is the only reasonable way to calculate x^y.
: , , , pow, . ! "" , exp() log().