phy_position_xprevious;
Returns: Real
This variable can be used to get (or to set) the previous x
position of the instance within the game room physics world. This
is the position of the instance within the physics world in the
previous step to the current one.
xx = phy_position_xprevious;
yy = phy_position_yprevious;
The above code stores the previous x and y position for the physics enabled instance in two variables.