[fyi1183]

... with a bias if X is not a power of 2.

[Retric]

Depends on the maximum range provided. If both part's pick a X bit number then you need a power of 2. If they pick a number 1 to X then can use X.

[fyi1183]

You're right of course. Just remember to use addition mod X instead of xor in that case to combine the choices.