(12C Platinum) Day of Easter

[bshoring]

For what it's worth, I'm posting my program for the HP-38C simulator, RPN-38CX. Since this simulator is limited to 99 steps, I loaded all the constants into registers, even financial registers, and replaced many of the arithmetic operators with RCL arithmetic to save steps. This modified program works for most years, but gives a result that is off by one week for 1930, 1950, 1970, 1974, and 1994 in the last century and 2025, 2045, 2065, 2069 & 2089 in the current century. I'm hoping someone might spot where this is going wrong for those years. I suspect it may be a result of the simulator having much greater internal precision (about 15-16 digits) than an actual HP-12C platinum. I think some of you have the RPN-38 CX simulator.

This program requires the following constants be loaded in order to work and for the date format to be set to D.MY format. If you select and copy all of the constants, you can copy to the display of RPN-38 CX and they will be pasted into the correct registers.

R5: 100
R6: 17
R7: 1
R8: 25
R9: 3
R.0: 4
R.1: 19
R.2: 30
R.3: 11
R.4: 2
R.5: 7
R.6: 40
R.7: 44
R.8: 31
R.9: 28
n: 15
i: 29
PV: 21
PMT: 27
FV: 0.000001

Program listing: (in program mode, copy and paste the program steps to the display to copy the entire program)

01 - 21 0 STO 0
02 - 22 71 5 RCL ÷ 5
03 - 24 61 INTGR
04 - 21 1 STO 1
05 - 21 4 STO 4
06 - 31 ENTER
07 - 86 71 0 RCL ÷ .0
08 - 24 61 INTGR
09 - 21 41 4 STO − 4
10 - 25 33 R↓
11 - 31 ENTER
12 - 22 41 6 RCL − 6
13 - 22 71 8 RCL ÷ 8
14 - 24 61 INTGR
15 - 21 3 STO 3
16 - 41 −
17 - 22 71 9 RCL ÷ 9
18 - 24 61 INTGR
19 - 21 41 4 STO − 4
20 - 22 11 RCL n
21 - 21 51 4 STO + 4
22 - 22 0 RCL 0
23 - 86 71 1 RCL ÷ .1
24 - 25 61 FRAC
25 - 86 61 1 RCL × .1
26 - 21 2 STO 2
27 - 86 61 1 RCL × .1
28 - 21 51 4 STO + 4
29 - 22 4 RCL 4
30 - 86 71 2 RCL ÷ .2
31 - 25 61 FRAC
32 - 86 61 2 RCL × .2
33 - 21 4 STO 4
34 - 22 14 RCL PMT
35 - 22 4 RCL 4
36 - 25 5 x≤y
37 - 25 7 53 GTO 53
38 - 22 12 RCL i
39 - 22 4 RCL 4
40 - 22 51 7 RCL + 7
41 - 71 ÷
42 - 24 61 INTGR
43 - 61 ×
44 - 1 1
45 - 33 x≷y
46 - 41 −
47 - 22 13 RCL PV
48 - 22 41 2 RCL − 2
49 - 86 71 3 RCL ÷ .3
50 - 24 61 INTGR
51 - 61 ×
52 - 21 41 4 STO − 4
53 - 22 0 RCL 0
54 - 21 2 STO 2
55 - 86 71 0 RCL ÷ .0
56 - 24 61 INTGR
57 - 21 51 2 STO + 2
58 - 22 4 RCL 4
59 - 86 51 4 RCL + .4
60 - 22 41 1 RCL − 1
61 - 21 51 2 STO + 2
62 - 22 1 RCL 1
63 - 86 71 0 RCL ÷ .0
64 - 24 61 INTGR
65 - 21 51 2 STO + 2
66 - 22 2 RCL 2
67 - 86 71 5 RCL ÷ .5
68 - 25 61 FRAC
69 - 86 61 5 RCL × .5
70 - 21 2 STO 2
71 - 22 4 RCL 4
72 - 33 x≷y
73 - 41 −
74 - 21 3 STO 3
75 - 86 51 6 RCL + .6
76 - 86 71 7 RCL ÷ .7
77 - 24 61 INTGR
78 - 22 51 9 RCL + 9
79 - 21 1 STO 1
80 - 86 71 0 RCL ÷ .0
81 - 24 61 INTGR
82 - 86 61 8 RCL × .8
83 - 32 CHS
84 - 86 51 9 RCL + .9
85 - 22 51 3 RCL + 3
86 - 22 1 RCL 1
87 - 22 71 5 RCL ÷ 5
88 - 51 +
89 - 22 15 RCL FV
90 - 22 61 0 RCL × 0
91 - 51 +
92 - 25 7 00 GTO 00


Regards,
Bob