How can I create a self update loop in simulink for this (Ball Balancing Table)?

I'm currently trying to create a simulink model of ball balancing table. Inside of "accx, accy" boxes, there is acceleration equations of ball in terms of x and y. Inside of "posx, posy" boxes, there is trajectory equations of ball, you can see below;

function posy = posy(accy, time) %acc info comes from previous equation box you can see in block diagram

pos0y = -30; %initial position of ball
vely = accy.*time;

posy = pos0y + vely.*time + ((accy.*(time.*time))/2);

I wanted to make this function like this;

function posy = posy(accy, time) %acc info comes from previous equation box you can see in block diagram

pos0y = -30; %initial position of ball
vely = accy.*time;

despos = 15; %desired final destination, final position of ball

posy = pos0y + vely.*time + ((accy.*(time.*time))/2);

%HERE I NEED A LOOP IN ORDER TO UPDATE SOME VARIABLES UNTIL BALL REACH DESIRED POSITION
%AND WHEN THE BALL REACH THE DESIRED POSITION, ACC SHOULD BE 0 AND SIMULATION STOP

%Also if it's possible, table dimenisons are 30x30, it would be good if the
%ball reach the boundaries, motors adjust angles to change acceleration in
%order to prevent falling ball from table etc

As you can see in above, I need a loop but I'm kinda beginner in these types of things so I am not able to figure it out, I'm stucked. If you can help me, I would be really happy. If there is another and easier option for what I want, I'm ok with that too.

Thanks in advance whoever helps or not.