(42S) GETKEY Demonstration

[Eddie W. Shore]

Good day everyone, hope everything is well with you today!

How GETKEY Works

To find the GETKEY command: PGM.FCN menu ( [ (shift) ] [ 3 ] ), [ ↑ ], (GETK)

GETKEY puts the HP 42S on hold and awaits for you to press a key. Whatever key you press returns a key code. Shift+Key combinations are allowed. Key codes start at the upper left hand corner [ Σ+ ] with key code 1, going right then down, to the bottom right hand corner [ + ] with key code 37.

Hence:
[ Σ+ ] has code 1
[ 1/x ] has code 2
[ √x ] has code 3
[ LOG ] has code 4
and so on.

Shift+Key combinations add 37 to the key code.
[ (shift) ] [ Σ+ ] has code 38
[ (shift) ] [ 1/x ] has code 39
[ (shift) ] [ √x ] has code 40
[ (shift) ] [ LOG ] has code 41
and so on.

There is no key code for the shift key alone.

The key code is returned to the X stack, which can be stored and analyzed. Pretty simple.

HP 42S/DM42/Free 42 Program: TABU

Raw file: tabulate.raw - Download: https://drive.google.com/file/d/1FKl-rWR...sp=sharing

Running TABU:

You will see a running total, starting with 0. Press [ 1 ] to add 1, [ 2 ] to add 2, or [ 3 ] to add 3 to the total. Any other key will exit the program.

Key codes used: [ 1 ]: 29, [ 2 ]: 30, [ 3 ]: 31

Code:

00 { 62-Byte Prgm }
01▸LBL "TABU"
02 0
03 STO 00
04▸LBL 10
05 GETKEY
06 STO 01
07 32
08 X<Y?
09 GTO 11
10 R↓
11 28
12 X>Y?
13 GTO 11
14 R↓
15 28
16 -
17 STO+ 00
18 CLA
19 "TOTAL: "
20 ARCL 00
21 AVIEW
22 GTO 10
23▸LBL 11
24 CLA
25 "FINAL: "
26 ARCL 00
27 AVIEW
28 .END.

HP 42S/DM42/Free 42 Program: BUILD

Raw file: build.raw - Download: https://drive.google.com/file/d/1gOg5oCG...sp=sharing

Running BUILD: A mathematical statement is generated with two random integers between -100 and 100. The RAN command uses the range 0 ≤ n < 1 with n ≠ 1 for all results. To get the range wanted, I use the subroutine RAN 201 * 100 - IP (integer(201*RAN) - 100) to get the range -100 ≤ n < 101.

Key codes used: [ + ]: 37, [ - ]: 32, [ × ]: 27

Any other key repeats the cycle until one of the acceptable keys are pressed.

Code:

00 { 150-Byte Prgm }
01▸LBL "BUILD"
02 ALL
03 XEQ 00
04 STO 01
05 XEQ 00
06 STO 02
07 GTO 01
08▸LBL 00
09 RAN
10 201
11 ×
12 100
13 -
14 IP
15 RTN
16▸LBL 01
17 RCL 01
18 RCL+ 02
19 STO 03
20 RCL 01
21 RCL- 02
22 STO 04
23 RCL 01
24 RCL× 02
25 STO 05
26▸LBL 02
27 CLA
28 "+, -, ×?"
29 AVIEW
30 GETKEY
31 37
32 X=Y?
33 GTO 03
34 R↓
35 32
36 X=Y?
37 GTO 04
38 R↓
39 27
40 X=Y?
41 GTO 05
42 GTO 02
43▸LBL 03
44 CLA
45 ARCL 01
46 ├" + "
47 ARCL 02
48 ├" = "
49 ARCL 03
50 GTO 06
51▸LBL 04
52 CLA
53 ARCL 01
54 ├" - "
55 ARCL 02
56 ├" = "
57 ARCL 04
58 GTO 06
59▸LBL 05
60 CLA
61 ARCL 01
62 ├" × "
63 ARCL 02
64 ├" = "
65 ARCL 05
66 GTO 06
67▸LBL 06
68 AVIEW
69 END

Example results (results will vary):

-53 + -32 = -85
93 - 19 = 74
41 × -15 = -615

And that concludes the demonstration on GETKEY.