Why is my TI-84+ program running so slow?

I've programmed a simple pong program into my TI-84+. However, after the "ball" moves about 30 times, the program starts slowing, eventually to a point at which the game is close to unplayable. Can anyone offer a suggestion as to why this may be happening?
Update: AxesOff ClrDraw 0- Xmin 95- Xmax 0- Ymin 63- Ymax 1- Xscl 1- Yscl 1- D #Direction 47- X #Ball Coords 26- Z #Ball Coords 26- U #User paddle 26- C #Computer paddle 0- F #User score 0- G #Comp score Lbl M #Main Text(5,5,F) #Score Text(5,12,G) #Score Pt-On(2,U,2) #User Paddle Pt-On(2,U+3,2) #User... show more AxesOff
ClrDraw
0- Xmin
95- Xmax
0- Ymin
63- Ymax
1- Xscl
1- Yscl
1- D #Direction
47- X #Ball Coords
26- Z #Ball Coords
26- U #User paddle
26- C #Computer paddle
0- F #User score
0- G #Comp score
Lbl M #Main
Text(5,5,F) #Score
Text(5,12,G) #Score
Pt-On(2,U,2) #User Paddle
Pt-On(2,U+3,2) #User Paddle
Pt-On(2,C,2) #Comp Paddle
Pt-On(2,C+3,2) #Comp Paddle
Pt-On(X,Z,2) #Ball
getKey- K #Key pressed
If K=25 #If up arrow pressed
Then
Pt-Off(2,U,2) # remove paddle
Pt-Off(2,U+3,2)
U+5- U #raise paddle 5
Else
If K=34
Then
Pt-Off(2,U,2)
Pt-Off(2,U+3,2)
U-5- U
End
End
Pt-Off(93,C,2) #remove comp paddle
Pt-Off(93,C+3,2)
If Z C+3 #adjust according to ball location
Then
C+2- C
Else
if Z C
End
End
If D=1 #directions
Then
Goto D1
Else
If D=2
Then
Goto D2
Else
If D=3
Then
Goto D3
Else
Goto D4
End
End
End
Lbl D1
Pt-Off(X,Z,3) #remove ball
X+2- X #change ball coords
Z+2- Z
If Z =61 #change direction if ceiling or floor hit
Then
2- D
End
If X =90
Then
Goto CC #check to see if ball hit paddle or i
Update 2: Okay, the greater than or less than signs won't go through. If you see something like Z+2- Z, there should be an arrow there (it's assignment in ti-basic)
Update 3: About the Z C thing, there should be a less than or greater than sign there.
4 answers 4