Re: [MI400] Save file check sums

[Gene_Gaunt@xxxxxxxxxxxxxxx]

Foiling CPF5175 eh?  This is the first algorithm.  The second algorithm on
RISC requires a 2048-byte substitution table.

01. initialize a 68-byte workarea to binary zeros
02. at workarea pos 8: copy savefilerec pos 1-57 & 513-516 (61 bytes)
03. shift workarea one bit left
04. at workarea pos 7: ADDLC savefilerec pos 58-119 (62 bytes)
05. shift workarea one bit left
06. at workarea pos 6: ADDLC savefilerec pos 120-182 (63 bytes)
07. shift workarea one bit left
08. at workarea pos 5: ADDLC savefilerec pos 183-246 (64 bytes)
09. shift workarea one bit left
10. at workarea pos 4: ADDLC savefilerec pos 247-311 (65 bytes)
11. shift workarea one bit left
12. at workarea pos 3: ADDLC savefilerec pos 312-377 (66 bytes)
13. shift workarea one bit left
14. at workarea pos 2: ADDLC savefilerec pos 446-512 (67 bytes)
15. shift workarea one bit left
16. at workarea pos 1: ADDLC savefilerec pos 378-445 (68 bytes)
17. initialize checksum (savefilerec pos 517-528) to binary zeros
18. at savefilerec pos 524: copy workarea pos 1-5 (5 bytes)
19. shift checksum one bit left
20. at savefilerec pos 523: ADDLC workarea pos 6-11 (6 bytes)
21. shift checksum one bit left
22. at savefilerec pos 522: ADDLC workarea pos 12-18 (7 bytes)
23. shift checksum one bit left
24. at savefilerec pos 521: ADDLC workarea pos 19-26 (8 bytes)
25. shift checksum one bit left
26. at savefilerec pos 520: ADDLC workarea pos 27-35 (9 bytes)
27. shift checksum one bit left
28. at savefilerec pos 519: ADDLC workarea pos 36-45 (10 bytes)
29. shift checksum one bit left
30. at savefilerec pos 518: ADDLC workarea pos 58-68 (11 bytes)
31. shift checksum one bit left
32. at savefilerec pos 517: ADDLC workarea pos 46-57 (12 bytes)
33. at savefilerec pos 517: XOR first record's timestamp (8 bytes)