Pong for the HP-65

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The program presented below will allow you to Ping-Pong against the HP-65. It was written by Jonathan Mills and appeared in the V4N6P49 issue of the PPC Journal (June 1977). Thanks to Jonathon wherever he is today!

You need to carefully store the constants presented below into the data registers prior to running the program.

Initial Instructions:
1) Initialize by pressing f-1 SF1, DSP . 1, and loading these data constants into the appropriate data memories:

   Data             Memory
   -0.1999999999    STO 1
   -0.9990999999    STO 2
   -0.9999990999    STO 3
    0.9999999990    STO 4
    0.5284163       STO 5
  997               STO 6
    0               STO 7
    1               STO 8

2) Double check that these registers have the correct constants in them.
3) Load the main program and press A. The display will show the ball (a moving O) shifting to the right of the display (the machine's side).
4) The machine will either return the ball or miss. If the machine misses, the score will be shown. See step 10 to interpret the score display.
5) If the ball IS returned, you MUST hit the ball by pressing the A key when the ball (a 0) is shown at the far left side of the display (your side of the playing field).
6) There is NO prompt shown telling you when to hit. You must time it properly to hit and return the ball!
7) After you have "hit" the ball (by pressing the A key), the program will stop. You must restart the game by pressing the A key again.
8) With some practice, you will be able to hit the A key two times in a row (to hit the ball and then to restart the game), giving the illusion that the ball actually "bounced" back to the HP-65's side.
9) If you have judged correctly in step 7, the ball will be returned back to the HP-65's side. Otherwise, the score will be displayed.
10) Scores are shown in the format PLAYER.MACHINE. Play is to 9 points. A machine win is displayed as 0.9, whereas a score in the middle of the game might appear as 8.6 (you are ahead of the HP-65 by a score of 8 to 6).
11) After a point is scored, the user will serve. (This is initiated by the Player pressing the A key again).
12) At the end of the game, pressing the A key will start a new game.

Try it. It's fun!

Program Listing: Email if you have any questions.

Line      Instruction
01         g
02         DSZ
03         GTO
04         1
05         f-1
06         TF 1
07         GTO
08         0
09         .
10         1
11         RCL 7
12         +
13         STO 7
14         f-1
15         INT
16         .
17         9
18         B
19         LBL
20         0
21         f
22         SF 1
23         RCL 2
24         D
25         RCL 3
26         D
27         RCL 4
28         D
29         LBL
30         E
31         f
32         TF 1
33         C
34         X > Y
35         GTO
36         1
37         1
38         RCL 7
39         +
40         STO 7
41         f
42         INT
43         9
44         LBL
45         B
46         f-1
47         SF 1
48         X NE Y
49         RCL 7
50         R/S
51         0
52         STO 7
53         RDN
54         R/S
55         LBL
56         1
57         1
58         STO 8
59         RCL 3
60         D
61         RCL 2
62         D
63         RCL 1
64         LBL
65         D
66         X NE Y
67         CLX
68         g NOP
69         g NOP
70         g NOP
71         g NOP
72         g NOP
73         g NOP
74         g NOP
75         g NOP
76         f-1
77         SF 1
78         g NOP
79         g NOP
80         g NOP
81         f-1
82         SF 1
83         g NOP
84         g NOP
85         g NOP
86         g NOP
87         g NOP
88         g NOP
89         RTN
90         LBL
91         C
92         .
93         4
94         RCL 5
95         RCL 6
96         *
97         f-1
98         INT
99         STO 5
100        RTN

That's it!

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