Fix an off-by-one bug in extract_pv()
In case we reach ply == PLY_MAX we exit the function
writing
pv[PLY_MAX] = MOVE_NONE;
And because SearchStack is defined as:
struct SearchStack {
Move pv[PLY_MAX];
Move currentMove;
.....
We end up with the unwanted assignment
SearchStack.currentMove = MOVE_NONE;
Fortunatly this is harmless because currentMove is not used where
extarct_pv() is called. But neverthless this is a bug that
needs to be fixed.
Thanks to Uri Blass for spotting out this.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>