(35S) LCPRNG Programme

[Gerald H]

A linear congruential pseudo-random integer generator programme.

The series of integers produced by the expression

( Seed * A + B ) mod M → Seed

for constant positive integer values of B, A & M (where the variables may range up to (10^12)-1) can appear random enough for many demands placed on a series of random numbers.

To use the programme:

1 Initialize, placing values
B
A
M
on the stack & XEQ O017.

2 Set Seed, one positive integer on stack & XEQ O028.

3 XEQ O001 to display the next value in the series & store the value as Seed

4 Either XEQ O001 or actuate R/S to display & seed further values.

Uses registers 4 to 7 & variables A, B, C, D, R, Y & Z.

(If you’re interested in the internals, lines 31 to 74 find Seed * A mod M, lines 75 to 80 accomplish addition mod M.)

1 LBL O
2 7►I*0
3 RCL+(I)
4 5►I*0
5 RCL+(I)
6 4►I*0
7 RCL+(I)
8 XEQ O031
9 6►I*0
10 RCL+(I)
11 XEQ O075
12 7►I*0
13 +
14 STO (I)
15 STOP
16 GTO O002
17 4►I
18 R↓
19 REGX►(I)
20 R↓
21 5►I
22 R↓
23 REGY►(I)
24 R↓
25 6►I
26 REGT►(I)
27 RTN
28 7►I
29 REGY►(I)
30 RTN
31 +/-
32 STO B
33 +/-
34 STO A
35 R↓
36 STO R
37 x<>y
38 REGX
39 1,000,000
40 RMDR
41 STO C
42 -
43 STO D
44 RCL R
45 REGX
46 1,000,000
47 RMDR
48 STO Z
49 -
50 STO Y
51 RCL* D
52 RCL B
53 RMDR
54 RCL Y
55 RCL* C
56 RCL A
57 RMDR
58 +
59 RCL B
60 RMDR
61 RCL D
62 RCL* Z
63 RCL A
64 RMDR
65 +
66 RCL B
67 RMDR
68 RCL Z
69 RCL* C
70 +
71 RCL A
72 RMDR
73 STO R
74 RTN
75 RCL B
76 RMDR
77 +
78 RCL A
79 RMDR
80 RTN

[Gerald H]

Sorry, line 16 had an error, now corrected ( was X002).