It would fire no times. -1 - 0 + 1 = 0. But I did leave off the ABS()

0, or ABS(y) - ABS(x) + 1 times (whichever is greater)."

Also, I left off a qualifier for what the step is set to.

If the step is abs(value) > 1, then I believe it is like so:

FOR i = x TO y STEP z
The number of loops will be: ABS(Y) MOD ABS(Z) - ABS(X) + 1 or 0, whichever is greater.