Trapped Game for the HP-25/HP-25C

Back to main page | Email me at: Gene!

The program presented below will play a game called "Trapped" for the HP-25 and HP-25C. It was written by Rich Messeder and appeared in the V5N6P25 issue of PPC Journal (July 1978). Thanks to Rich wherever he is today!

It's basically a high-low type of game, but it's small enough that you might even key it into an HP-25 without continuous memory.

Instructions:
1) Load the program into the calculator and change back to RUN mode.
2) Store the initial decimal seed into memory 0 (type STO 0)
3) Press f PRGM (this resets the program pointer to the start of the program memory).
4) Press R/S to start. Display shows 0.1000 as the starting boundaries.
5) Enter your guess for the number and press R/S.
6) The display now shows the new upper and lower boundaries depending on whether your guess was too high or too low.
7) Continue playing until you correctly guess the secret number. When you do do, the secret number will be flashed and your score (the number of guesses you took) will be left flashing in the display.
8) For a new game, go to step 3.

Program Listing: Email if you have any questions. 
Line      Instruction  Keycode(s)
01         f FIX 4      14 11 04
02         RCL 0        24 00
03         9            09
04         9            09
05         7            07
06         *            61
07         g FRAC       15 01
08         STO 0        23 00
09         EEX          33
10         3            03
11         STO 5        23 05
12         1            01
13         STO 4        23 04
14         STO 6        23 06
15         -            41
16         *            61
17         f INT        14 01
18         STO + 6      23 51 06
19         f STK        14 34
20         SIGMA+       25
21         RCL 4        24 04
22         RCL 5        24 05
23         EEX          33
24         4            04
25         /            71
26         +            51
27         R/S          74
28         STO 7        23 07
29         f X < Y      14 41
30         GTO 43       13 43
31         RCL 5        24 05
32         f X < Y      14 41
33         GTO 43       13 43
34         RCL 6        24 06
35         RCL 7        24 07
36         f X = Y      14 71
37         GTO 46       13 46
38         f X < Y      14 41
39         STO 4        23 04
40         f X > = Y    14 51
41         STO 5        23 05
42         GTO 20       13 20
43         CHS          39
44         f SQRT       14 02
45         GTO 20       13 20
46         f FIX 0      14 11 00
47         f PSE        14 74
48         RCL 3        24 03
49         ST0 - 3      23 41 03
That's it!