[MPaulHolmes]

Ya, the mulss takes a couple cycles off the normal multiply. I think because there are 4 variations:
mulss
mulus
mulsu
muluu

(signed signed)
(unsigned signed)
(signed unsigned)
(unsigned unsigned)

And if you know what type you are using, the compiler doesn't have to check and maybe saves a little time somehow?

Now for the sensorless,

Ealpha = Valpha - statorResistance*IAlpha - statorInductance*dIAlpha/dt
Ebeta = Vbeta - statorResistance*Ibeta - statorInductance*dIbeta/dt

(Valpha, Vbeta, Ialpha, and Ibeta are all just stuff that you get during the clarke and park transforms and inverse transforms. The steps are identical for ACIM and permanent magnet AC)

EDIT: OK I had made a mistake, and you can't just get the rotor flux angle that way. There's an offset that depends on the speed of the motor. Oh well. It's sort of working now though.