Here is the program itself and the program metadata.
This is documentation for the submarine game provided in the sixth edition of VIPER magazine. Firstly, follows is a view of the program when it is first loaded into the tool:
200-201 0512-0513 █▄▀ ▄▄▀▄ A2CD 41677 I ← 0717
202-203 0514-0515 ▀█▄█ ▀ 6938 26936 V9 ← 056
204-205 0516-0517 ▀▀▄█▄█ 6A1E 27166 VA ← 030
206-207 0518-0519 █▀▄▀▀ ▄▀ D9A2 55714 Draw 08×02 at V9,VA; VF ← XOR
208-209 0520-0521 █▄▀▄ ▀ A2D0 41680 I ← 0720
20A-20B 0522-0523 ▀▀ ▀ ▀▀ 6B00 27392 VB ← 000
20C-20D 0524-0525 ▀▀▄█▀▄ 6C1A 27674 VC ← 026
20E-20F 0526-0527 ██ ▀▀ █▀ DBC2 56258 Draw 08×02 at VB,VC; VF ← XOR
210-211 0528-0529 █▄▀▄ ▄▀ A2D4 41684 I ← 0724
212-213 0530-0531 ▀█▄▄█ 643C 25660 V4 ← 060
214-215 0532-0533 ▀▀ ██ 6606 26118 V6 ← 006
216-217 0534-0535 ▀█▄▀ ▀▄▄ D463 54371 Draw 08×03 at V4,V6; VF ← XOR
218-219 0536-0537 ▀▀ ▀▀▀ 6700 26368 V7 ← 000
21A-21B 0538-0539 ▀▀▄█ ▄ 6819 26649 V8 ← 025
21C-21D 0540-0541 ▄ █ █ 22A2 08866 Call 0674
21E-21F 0542-0543 ▄ █ ▄▄▀ 22AC 08876 Call 0684
220-221 0544-0545 ▀ ▀ 4800 18432 Skip next if V8 <> 000
222-223 0546-0547 ▄▄ █▄ ▀ 12D8 04824 Jump to 0728
224-225 0548-0549 ▀▀ ▄▀ █ 6509 25865 V5 ← 009
226-227 0550-0551 █▄▀▄ ▄█▄ A2D7 41687 I ← 0727
228-229 0552-0553 ▀▀ ▀▀ 6300 25344 V3 ← 000
22A-22B 0554-0555 ▀▀ ▀█ █ 6D05 27909 VD ← 005
22C-22D 0556-0557 █▀█ ▀▀ █ EDA1 60833 Skip next if VD <> key
22E-22F 0558-0559 ▀▀ ▀█ 6301 25345 V3 ← 001
230-231 0560-0561 ▀▄ ▀▀▀ 8E40 36416 VE ← V4
232-233 0562-0563 █▀█ ▀▀ █ EDA1 60833 Skip next if VD <> key
234-235 0564-0565 ▀█ █▀▀▀▄ DE51 56913 Draw 08×01 at VE,V5; VF ← XOR
236-237 0566-0567 ▄█▄▄▀ 123C 04668 Jump to 0572
238-239 0568-0569 █▀█ ▀▀ █ EDA1 60833 Skip next if VD <> key
23A-23B 0570-0571 ▄▄▀▄▄ ▀ 22D8 08920 Call 0728
23C-23D 0572-0573 █▄▀▄ ▄▀ A2D4 41684 I ← 0724
23E-23F 0574-0575 ▀█▄▀ ▀▄▄ D463 54371 Draw 08×03 at V4,V6; VF ← XOR
240-241 0576-0577 ▄ ▀ █ 1242 04674 Jump to 0578
242-243 0578-0579 ▄███▄█▄▄ 74FF 29951 V4 ← V4 + 255
244-245 0580-0581 ▀█▄▀ ▀▄▄ D463 54371 Draw 08×03 at V4,V6; VF ← XOR
246-247 0582-0583 █▄▀▄ ▀ A2D0 41680 I ← 0720
248-249 0584-0585 ██ ▀▀ █▀ DBC2 56258 Draw 08×02 at VB,VC; VF ← XOR
24A-24B 0586-0587 ▀▀ ▀█ ▀ CD04 52484 VD ← ??? AND 004
24C-24D 0588-0589 █▄ ▄▀▄▀▀ 8BD4 35796 VB ← VB + VD; VF ← overflow
24E-24F 0590-0591 ██ ▀▀ █▀ DBC2 56258 Draw 08×02 at VB,VC; VF ← XOR
250-251 0592-0593 ▀▀▀▀▀▀ 3F00 16128 Skip next if VF = 000
252-253 0594-0595 ▄ █ █ 1292 04754 Jump to 0658
254-255 0596-0597 █▄▀ ▄▄▀▄ A2CD 41677 I ← 0717
256-257 0598-0599 █▀▄▀▀ ▄▀ D9A2 55714 Draw 08×02 at V9,VA; VF ← XOR
258-259 0600-0601 ▀▀ ▀█▄█ CD07 52487 VD ← ??? AND 007
25A-25B 0602-0603 ▀ ▀▀ ▀ 4D00 19712 Skip next if VD <> 000
25C-25D 0604-0605 ▀▀▀▀ ▄█ 7903 30979 V9 ← V9 + 003
25E-25F 0606-0607 ▄████▄ █ 79FD 31229 V9 ← V9 + 253
260-261 0608-0609 █▀▄▀▀ ▄▀ D9A2 55714 Draw 08×02 at V9,VA; VF ← XOR
262-263 0610-0611 ▀▀▀▀▀▀ 3F00 16128 Skip next if VF = 000
264-265 0612-0613 ▄ ▀▄▄▀ 128C 04748 Jump to 0652
266-267 0614-0615 ▀ ▀▀ 4300 17152 Skip next if V3 <> 000
268-269 0616-0617 ▄▀▄ █ 122A 04650 Jump to 0554
26A-26B 0618-0619 █▄▀▄ ▄█▄ A2D7 41687 I ← 0727
26C-26D 0620-0621 ▀█ █▀▀▀▄ DE51 56913 Draw 08×01 at VE,V5; VF ← XOR
26E-26F 0622-0623 ▀ ▄▄█▄█ 451F 17695 Skip next if V5 <> 031
270-271 0624-0625 ▄ ▀ ▄█ 1286 04742 Jump to 0646
272-273 0626-0627 ▀▀▀ ▀▄▀ 7502 29954 V5 ← V5 + 002
274-275 0628-0629 ▀▀▀█▄ ▀▀ F318 62232 sound ← V3
276-277 0630-0631 ▀█ █▀▀▀▄ DE51 56913 Draw 08×01 at VE,V5; VF ← XOR
278-279 0632-0633 ▀▀▀▀▀█ 3F01 16129 Skip next if VF = 001
27A-27B 0634-0635 ▄█▄▄▀ 123C 04668 Jump to 0572
27C-27D 0636-0637 ▀▀▄██▄█ 6D1F 27935 VD ← 031
27E-27F 0638-0639 ▀▄ ▄▀▀▄▀ 8D52 36178 VD ← VD AND V5
280-281 0640-0641 ▀ ▄██▄█ 4D1F 19743 Skip next if VD <> 031
282-283 0642-0643 ▄ ▀▄▄▀ 128C 04748 Jump to 0652
284-285 0644-0645 ▄ █ █ 1292 04754 Jump to 0658
286-287 0646-0647 ▄ █ ▄▄▀ 22AC 08876 Call 0684
288-289 0648-0649 ▄████▄▄▄ 78FF 30975 V8 ← V8 + 255
28A-28B 0650-0651 █▄▄█ 121E 04638 Jump to 0542
28C-28D 0652-0653 ▄ █ █ 22A2 08866 Call 0674
28E-28F 0654-0655 ▀▀▀ █▀█ 7705 30469 V7 ← V7 + 005
290-291 0656-0657 ▄ █ ▄█ 1296 04758 Jump to 0662
292-293 0658-0659 ▄ █ █ 22A2 08866 Call 0674
294-295 0660-0661 ▀▀▀▄▀█▀ 770A 30474 V7 ← V7 + 010
296-297 0662-0663 ▄ █ █ 22A2 08866 Call 0674
298-299 0664-0665 ▀▀ ▀▀▄█ 6D03 27907 VD ← 003
29A-29B 0666-0667 ▀▀▀██▀ ▀ FD18 64792 sound ← VD
29C-29D 0668-0669 █▄▀▄ ▄█▄ A2D7 41687 I ← 0727
29E-29F 0670-0671 ▀█ █▀▀▀▄ DE51 56913 Draw 08×01 at VE,V5; VF ← XOR
2A0-2A1 0672-0673 ▄ ▀ ▄█ 1286 04742 Jump to 0646
2A2-2A3 0674-0675 █▄█▄▄ ▀ A2F8 41720 I ← 0760
2A4-2A5 0676-0677 ▀▀██ ▀██ F733 63283 V7 as BCD stored from I
2A6-2A7 0678-0679 ▀▀ ▀▀ 6300 25344 V3 ← 000
2A8-2A9 0680-0681 ▄ █▄ ▄█ 22B6 08886 Call 0694
2AA-2AB 0682-0683 ▄▄▄ ▄▄▄ 00EE 00238 Return
2AC-2AD 0684-0685 █▄█▄▄ ▀ A2F8 41720 I ← 0760
2AE-2AF 0686-0687 ▀▀██▀ ▄▄ F833 63539 V8 as BCD stored from I
2B0-2B1 0688-0689 ▀█▄ █▀ 6332 25394 V3 ← 050
2B2-2B3 0690-0691 ▄ █▄ ▄█ 22B6 08886 Call 0694
2B4-2B5 0692-0693 ▄▄▄ ▄▄▄ 00EE 00238 Return
2B6-2B7 0694-0695 ▀▀ ▀▀ ▀ 6D00 27904 VD ← 000
2B8-2B9 0696-0697 ▀██▀ ▄▀▄ F265 62053 Load V0→V2; I ← I + 03
2BA-2BB 0698-0699 ▀▀█▀▄ ▄ F029 61481 I ← digit sprite of V0
2BC-2BD 0700-0701 ██ █ ▄▀█ D3D5 54229 Draw 08×05 at V3,VD; VF ← XOR
2BE-2BF 0702-0703 ▀▀▀ ▄▀█ 7305 29445 V3 ← V3 + 005
2C0-2C1 0704-0705 ▀▀█▀▄ █ F129 61737 I ← digit sprite of V1
2C2-2C3 0706-0707 ██ █ ▄▀█ D3D5 54229 Draw 08×05 at V3,VD; VF ← XOR
2C4-2C5 0708-0709 ▀▀▀ ▄▀█ 7305 29445 V3 ← V3 + 005
2C6-2C7 0710-0711 ▀▀█▀▄ ▀▄ F229 61993 I ← digit sprite of V2
2C8-2C9 0712-0713 ██ █ ▄▀█ D3D5 54229 Draw 08×05 at V3,VD; VF ← XOR
2CA-2CB 0714-0715 ▄▄▄ ▄▄▄ 00EE 00238 Return
2CC-2CD 0716-0717 ▄ ▀ 0108 00264 Jump to COSMAC VIP 0264
2CE-2CF 0718-0719 █████▀▀ 7F7C 32636 VF ← VF + 124
2D0-2D1 0720-0721 ▄▄█▄▄ 083E 02110 Jump to COSMAC VIP 2110
2D2-2D3 0722-0723 ▀▀ ▄ 6008 24584 V0 ← 008
2D4-2D5 0724-0725 ▄██▄ 183C 06204 Jump to 2108
2D6-2D7 0726-0727 ▀▀▀▀█▀▀▀ FF08 65288
2D8-2D9 0728-0729 ▀ ▀ ▀▀ A300 41728 I ← 0768
2DA-2DB 0730-0731 ▀▀▄ ▀█ 6311 25361 V3 ← 017
2DC-2DD 0732-0733 ▀▀ █▀▄█ 6D0B 27915 VD ← 011
2DE-2DF 0734-0735 ██ █ ▄▀█ D3D5 54229 Draw 08×05 at V3,VD; VF ← XOR
2E0-2E1 0736-0737 ▀ ▀ ▄▀█ A305 41733 I ← 0773
2E2-2E3 0738-0739 ▀▀▄▄ ▀█ 6319 25369 V3 ← 025
2E4-2E5 0740-0741 ██ █ ▄▀█ D3D5 54229 Draw 08×05 at V3,VD; VF ← XOR
2E6-2E7 0742-0743 ▀ ▀ ▄ █▀ A30A 41738 I ← 0778
2E8-2E9 0744-0745 ▀█ ██ 6323 25379 V3 ← 035
2EA-2EB 0746-0747 ██ █ ▄▀█ D3D5 54229 Draw 08×05 at V3,VD; VF ← XOR
2EC-2ED 0748-0749 ▀ ▀ ▄▄██ A30F 41743 I ← 0783
2EE-2EF 0750-0751 ▀█ ▄ ██ 632B 25387 V3 ← 043
2F0-2F1 0752-0753 ██ █ ▄▀█ D3D5 54229 Draw 08×05 at V3,VD; VF ← XOR
2F2-2F3 0754-0755 ▀▀ ▀▀ 6300 25344 V3 ← 000
2F4-2F5 0756-0757 ▄▄▄█ ▄▀ 12F4 04852 Jump to 0756
2F6-2F7 0758-0759 ▀▀ █▀▄█ 6D0B 27915 VD ← 011
2F8-2F9 0760-0761 ▄ 0001 00001 Jump to COSMAC VIP 0001
2FA-2FB 0762-0763 ▀ 0400 01024 Jump to COSMAC VIP 1024
2FC-2FD 0764-0765 ▄▄▄ ▄▄▄ 00EE 00238 Return
2FE-2FF 0766-0767 ▄ 0001 00001 Jump to COSMAC VIP 0001
300-301 0768-0769 █▀▀ █▀█ EE8A 61066
302-303 0770-0771 █ ▄ █ █ 8AAA 35498
304-305 0772-0773 ███ ███▄ EEEF 61167
306-307 0774-0775 █ █ █ █ A5A5 42405 I ← 1445
308-309 0776-0777 █▄█ ▄█▄█ A5EF 42479 I ← 1519
30A-30B 0778-0779 ▀█▀█ █ 7A2A 31274 VA ← VA + 042
30C-30D 0780-0781 █▀█ ▀█ 3B29 15145 Skip next if VB = 041
30E-30F 0782-0783 ▄▀███ ▄▀ 79BA 31162 V9 ← V9 + 186
310-311 0784-0785 █ █▄ █ A2B2 41650 I ← 0690
312-313 0786-0787 █▄▄ ▄ 203A 08250 Call 0058
314-315 0788-0789 ██▄▀▄ 343A 13370 Skip next if V4 = 058
316-317 0790-0791 ▄▄▀█▀█▄ 3CD6 15574 Skip next if VC = 214
318-319 0792-0793 ▀ █▄█ 541C 21532
31A-31B 0794-0795 ▄ ▀▀ 0C40 03136 Jump to COSMAC VIP 3136
31C-31D 0796-0797 ▀ ▄▀▀█▀▄ 9E25 40485
31E-31F 0798-0799 ▀▀ █▄ 680C 26636 V8 ← 012Follows now is the fully annotated view of the program when it is loaded into the tool:
200-201 0512-0513 █▄▀ ▄▄▀▄ A2CD 41677 I ← big enemy
202-203 0514-0515 ▀█▄█ ▀ 6938 26936 V9 ← 056
204-205 0516-0517 ▀▀▄█▄█ 6A1E 27166 VA ← 030
206-207 0518-0519 █▀▄▀▀ ▄▀ D9A2 55714 Draw 08×02 at V9,VA; VF ← XOR
208-209 0520-0521 █▄▀▄ ▀ A2D0 41680 I ← small enemy
20A-20B 0522-0523 ▀▀ ▀ ▀▀ 6B00 27392 VB ← 000
20C-20D 0524-0525 ▀▀▄█▀▄ 6C1A 27674 VC ← 026
20E-20F 0526-0527 ██ ▀▀ █▀ DBC2 56258 Draw 08×02 at VB,VC; VF ← XOR
210-211 0528-0529 █▄▀▄ ▄▀ A2D4 41684 I ← you
212-213 0530-0531 ▀█▄▄█ 643C 25660 V4 ← 060
214-215 0532-0533 ▀▀ ██ 6606 26118 V6 ← 006
216-217 0534-0535 ▀█▄▀ ▀▄▄ D463 54371 Draw 08×03 at V4,V6; VF ← XOR
218-219 0536-0537 ▀▀ ▀▀▀ 6700 26368 V7 ← 000
21A-21B 0538-0539 ▀▀▄█ ▄ 6819 26649 V8 ← 025
21C-21D 0540-0541 ▄ █ █ 22A2 08866 Call show score
21E-21F 0542-0543 ▄ █ ▄▄▀ 22AC 08876 start Call show count
220-221 0544-0545 ▀ ▀ 4800 18432 Skip next if V8 <> 000
222-223 0546-0547 ▄▄ █▄ ▀ 12D8 04824 Jump to end
224-225 0548-0549 ▀▀ ▄▀ █ 6509 25865 V5 ← 009
226-227 0550-0551 █▄▀▄ ▄█▄ A2D7 41687 I ← bomb
228-229 0552-0553 ▀▀ ▀▀ 6300 25344 V3 ← 000
22A-22B 0554-0555 ▀▀ ▀█ █ 6D05 27909 control VD ← 005
22C-22D 0556-0557 █▀█ ▀▀ █ EDA1 60833 Skip next if VD <> key
22E-22F 0558-0559 ▀▀ ▀█ 6301 25345 V3 ← 001
230-231 0560-0561 ▀▄ ▀▀▀ 8E40 36416 VE ← V4
232-233 0562-0563 █▀█ ▀▀ █ EDA1 60833 Skip next if VD <> key
234-235 0564-0565 ▀█ █▀▀▀▄ DE51 56913 Draw 08×01 at VE,V5; VF ← XOR
236-237 0566-0567 ▄█▄▄▀ 123C 04668 Jump to prime
238-239 0568-0569 █▀█ ▀▀ █ EDA1 60833 skipped Skip next if VD <> key
23A-23B 0570-0571 ▄▄▀▄▄ ▀ 22D8 08920 also skipped Call end
23C-23D 0572-0573 █▄▀▄ ▄▀ A2D4 41684 prime I ← you
23E-23F 0574-0575 ▀█▄▀ ▀▄▄ D463 54371 Draw 08×03 at V4,V6; VF ← XOR
240-241 0576-0577 ▄ ▀ █ 1242 04674 Jump to next
242-243 0578-0579 ▄███▄█▄▄ 74FF 29951 next V4 ← V4 + 255
244-245 0580-0581 ▀█▄▀ ▀▄▄ D463 54371 Draw 08×03 at V4,V6; VF ← XOR
246-247 0582-0583 █▄▀▄ ▀ A2D0 41680 I ← small enemy
248-249 0584-0585 ██ ▀▀ █▀ DBC2 56258 Draw 08×02 at VB,VC; VF ← XOR
24A-24B 0586-0587 ▀▀ ▀█ ▀ CD04 52484 VD ← ??? AND 004
24C-24D 0588-0589 █▄ ▄▀▄▀▀ 8BD4 35796 VB ← VB + VD; VF ← overflow
24E-24F 0590-0591 ██ ▀▀ █▀ DBC2 56258 Draw 08×02 at VB,VC; VF ← XOR
250-251 0592-0593 ▀▀▀▀▀▀ 3F00 16128 Skip next if VF = 000
252-253 0594-0595 ▄ █ █ 1292 04754 Jump to small hit
254-255 0596-0597 █▄▀ ▄▄▀▄ A2CD 41677 I ← big enemy
256-257 0598-0599 █▀▄▀▀ ▄▀ D9A2 55714 Draw 08×02 at V9,VA; VF ← XOR
258-259 0600-0601 ▀▀ ▀█▄█ CD07 52487 VD ← ??? AND 007
25A-25B 0602-0603 ▀ ▀▀ ▀ 4D00 19712 Skip next if VD <> 000
25C-25D 0604-0605 ▀▀▀▀ ▄█ 7903 30979 V9 ← V9 + 003
25E-25F 0606-0607 ▄████▄ █ 79FD 31229 V9 ← V9 + 253
260-261 0608-0609 █▀▄▀▀ ▄▀ D9A2 55714 Draw 08×02 at V9,VA; VF ← XOR
262-263 0610-0611 ▀▀▀▀▀▀ 3F00 16128 Skip next if VF = 000
264-265 0612-0613 ▄ ▀▄▄▀ 128C 04748 Jump to big hit
266-267 0614-0615 ▀ ▀▀ 4300 17152 Skip next if V3 <> 000
268-269 0616-0617 ▄▀▄ █ 122A 04650 Jump to control
26A-26B 0618-0619 █▄▀▄ ▄█▄ A2D7 41687 I ← bomb
26C-26D 0620-0621 ▀█ █▀▀▀▄ DE51 56913 Draw 08×01 at VE,V5; VF ← XOR
26E-26F 0622-0623 ▀ ▄▄█▄█ 451F 17695 Skip next if V5 <> 031
270-271 0624-0625 ▄ ▀ ▄█ 1286 04742 Jump to decrease
272-273 0626-0627 ▀▀▀ ▀▄▀ 7502 29954 V5 ← V5 + 002
274-275 0628-0629 ▀▀▀█▄ ▀▀ F318 62232 sound ← V3
276-277 0630-0631 ▀█ █▀▀▀▄ DE51 56913 Draw 08×01 at VE,V5; VF ← XOR
278-279 0632-0633 ▀▀▀▀▀█ 3F01 16129 Skip next if VF = 001
27A-27B 0634-0635 ▄█▄▄▀ 123C 04668 Jump to prime
27C-27D 0636-0637 ▀▀▄██▄█ 6D1F 27935 VD ← 031
27E-27F 0638-0639 ▀▄ ▄▀▀▄▀ 8D52 36178 VD ← VD AND V5
280-281 0640-0641 ▀ ▄██▄█ 4D1F 19743 Skip next if VD <> 031
282-283 0642-0643 ▄ ▀▄▄▀ 128C 04748 Jump to big hit
284-285 0644-0645 ▄ █ █ 1292 04754 Jump to small hit
286-287 0646-0647 ▄ █ ▄▄▀ 22AC 08876 decrease Call show count
288-289 0648-0649 ▄████▄▄▄ 78FF 30975 V8 ← V8 + 255
28A-28B 0650-0651 █▄▄█ 121E 04638 Jump to start
28C-28D 0652-0653 ▄ █ █ 22A2 08866 big hit Call show score
28E-28F 0654-0655 ▀▀▀ █▀█ 7705 30469 V7 ← V7 + 005
290-291 0656-0657 ▄ █ ▄█ 1296 04758 Jump to shared
292-293 0658-0659 ▄ █ █ 22A2 08866 small hit Call show score
294-295 0660-0661 ▀▀▀▄▀█▀ 770A 30474 V7 ← V7 + 010
296-297 0662-0663 ▄ █ █ 22A2 08866 shared Call show score
298-299 0664-0665 ▀▀ ▀▀▄█ 6D03 27907 VD ← 003
29A-29B 0666-0667 ▀▀▀██▀ ▀ FD18 64792 sound ← VD
29C-29D 0668-0669 █▄▀▄ ▄█▄ A2D7 41687 I ← bomb
29E-29F 0670-0671 ▀█ █▀▀▀▄ DE51 56913 Draw 08×01 at VE,V5; VF ← XOR
2A0-2A1 0672-0673 ▄ ▀ ▄█ 1286 04742 Jump to decrease
2A2-2A3 0674-0675 █▄█▄▄ ▀ A2F8 41720 show score I ← scratch
2A4-2A5 0676-0677 ▀▀██ ▀██ F733 63283 V7 as BCD stored from I
2A6-2A7 0678-0679 ▀▀ ▀▀ 6300 25344 V3 ← 000
2A8-2A9 0680-0681 ▄ █▄ ▄█ 22B6 08886 Call show
2AA-2AB 0682-0683 ▄▄▄ ▄▄▄ 00EE 00238 Return
2AC-2AD 0684-0685 █▄█▄▄ ▀ A2F8 41720 show count I ← scratch
2AE-2AF 0686-0687 ▀▀██▀ ▄▄ F833 63539 V8 as BCD stored from I
2B0-2B1 0688-0689 ▀█▄ █▀ 6332 25394 V3 ← 050
2B2-2B3 0690-0691 ▄ █▄ ▄█ 22B6 08886 Call show
2B4-2B5 0692-0693 ▄▄▄ ▄▄▄ 00EE 00238 Return
2B6-2B7 0694-0695 ▀▀ ▀▀ ▀ 6D00 27904 show VD ← 000
2B8-2B9 0696-0697 ▀██▀ ▄▀▄ F265 62053 Load V0→V2; I ← I + 03
2BA-2BB 0698-0699 ▀▀█▀▄ ▄ F029 61481 I ← digit sprite of V0
2BC-2BD 0700-0701 ██ █ ▄▀█ D3D5 54229 Draw 08×05 at V3,VD; VF ← XOR
2BE-2BF 0702-0703 ▀▀▀ ▄▀█ 7305 29445 V3 ← V3 + 005
2C0-2C1 0704-0705 ▀▀█▀▄ █ F129 61737 I ← digit sprite of V1
2C2-2C3 0706-0707 ██ █ ▄▀█ D3D5 54229 Draw 08×05 at V3,VD; VF ← XOR
2C4-2C5 0708-0709 ▀▀▀ ▄▀█ 7305 29445 V3 ← V3 + 005
2C6-2C7 0710-0711 ▀▀█▀▄ ▀▄ F229 61993 I ← digit sprite of V2
2C8-2C9 0712-0713 ██ █ ▄▀█ D3D5 54229 Draw 08×05 at V3,VD; VF ← XOR
2CA-2CB 0714-0715 ▄▄▄ ▄▄▄ 00EE 00238 Return
2CC 0716 █ 01 001
2CD 0717 █ 08 008 big enemy
2CE 0718 ███████ 7F 127
2CF 0719 █████ 7C 124
2D0 0720 █ 08 008 small enemy
2D1 0721 █████ 3E 062
2D2 0722 ██ 60 096
2D3 0723 █ 08 008
2D4 0724 ██ 18 024 you
2D5 0725 ████ 3C 060
2D6 0726 ████████ FF 255
2D7 0727 █ 08 008 bomb
2D8-2D9 0728-0729 ▀ ▀ ▀▀ A300 41728 end I ← go
2DA-2DB 0730-0731 ▀▀▄ ▀█ 6311 25361 V3 ← 017
2DC-2DD 0732-0733 ▀▀ █▀▄█ 6D0B 27915 VD ← 011
2DE-2DF 0734-0735 ██ █ ▄▀█ D3D5 54229 Draw 08×05 at V3,VD; VF ← XOR
2E0-2E1 0736-0737 ▀ ▀ ▄▀█ A305 41733 I ← od
2E2-2E3 0738-0739 ▀▀▄▄ ▀█ 6319 25369 V3 ← 025
2E4-2E5 0740-0741 ██ █ ▄▀█ D3D5 54229 Draw 08×05 at V3,VD; VF ← XOR
2E6-2E7 0742-0743 ▀ ▀ ▄ █▀ A30A 41738 I ← by
2E8-2E9 0744-0745 ▀█ ██ 6323 25379 V3 ← 035
2EA-2EB 0746-0747 ██ █ ▄▀█ D3D5 54229 Draw 08×05 at V3,VD; VF ← XOR
2EC-2ED 0748-0749 ▀ ▀ ▄▄██ A30F 41743 I ← e!
2EE-2EF 0750-0751 ▀█ ▄ ██ 632B 25387 V3 ← 043
2F0-2F1 0752-0753 ██ █ ▄▀█ D3D5 54229 Draw 08×05 at V3,VD; VF ← XOR
2F2-2F3 0754-0755 ▀▀ ▀▀ 6300 25344 V3 ← 000
2F4-2F5 0756-0757 ▄▄▄█ ▄▀ 12F4 04852 self Jump to self
2F6 0758 ██ ██ █ 6D 109
2F7 0759 █ ██ 0B 011
2F8 0760 00 000 scratch
2F9 0761 █ 01 001
2FA 0762 █ 04 004
2FB 0763 00 000
2FC 0764 00 000
2FD 0765 ███ ███ EE 238
2FE 0766 00 000
2FF 0767 █ 01 001
300 0768 ███ ███ EE 238 go
301 0769 █ █ █ 8A 138
302 0770 █ █ █ 8A 138
303 0771 █ █ █ █ AA 170
304 0772 ███ ███ EE 238
305 0773 ███ ████ EF 239 od
306 0774 █ █ █ █ A5 165
307 0775 █ █ █ █ A5 165
308 0776 █ █ █ █ A5 165
309 0777 ███ ████ EF 239
30A 0778 ████ █ 7A 122 by
30B 0779 █ █ █ 2A 042
30C 0780 ███ ██ 3B 059
30D 0781 █ █ █ 29 041
30E 0782 ████ █ 79 121
30F 0783 █ ███ █ BA 186 e!
310 0784 █ █ █ A2 162
311 0785 █ ██ █ B2 178
312 0786 █ 20 032
313 0787 ███ █ 3A 058
314 0788 ██ █ 34 052
315 0789 ███ █ 3A 058
316 0790 ████ 3C 060
317 0791 ██ █ ██ D6 214
318 0792 █ █ █ 54 084
319 0793 ███ 1C 028
31A 0794 ██ 0C 012
31B 0795 █ 40 064
31C 0796 █ ████ 9E 158
31D 0797 █ █ █ 25 037
31E 0798 ██ █ 68 104
31F 0799 ██ 0C 012The register usage is as follows:
The game begins by drawing the big enemy sprite in the lower right corner of the screen:
200-201 0512-0513 █▄▀ ▄▄▀▄ A2CD 41677 I ← big enemy
202-203 0514-0515 ▀█▄█ ▀ 6938 26936 V9 ← 056
204-205 0516-0517 ▀▀▄█▄█ 6A1E 27166 VA ← 030
206-207 0518-0519 █▀▄▀▀ ▄▀ D9A2 55714 Draw 08×02 at V9,VA; VF ← XORThen the small enemy sprite is drawn in the lower left corner. Note that these sprites are drawn at different heights; this is to simplify collision detection:
208-209 0520-0521 █▄▀▄ ▀ A2D0 41680 I ← small enemy
20A-20B 0522-0523 ▀▀ ▀ ▀▀ 6B00 27392 VB ← 000
20C-20D 0524-0525 ▀▀▄█▀▄ 6C1A 27674 VC ← 026
20E-20F 0526-0527 ██ ▀▀ █▀ DBC2 56258 Draw 08×02 at VB,VC; VF ← XORFollowing that, the you sprite, representing the player's submarine, is drawn at the top right corner of the screen, clipped by the right edge:
210-211 0528-0529 █▄▀▄ ▄▀ A2D4 41684 I ← you
212-213 0530-0531 ▀█▄▄█ 643C 25660 V4 ← 060
214-215 0532-0533 ▀▀ ██ 6606 26118 V6 ← 006
216-217 0534-0535 ▀█▄▀ ▀▄▄ D463 54371 Draw 08×03 at V4,V6; VF ← XORThe score and bomb counts are then initialized and the score is displayed:
218-219 0536-0537 ▀▀ ▀▀▀ 6700 26368 V7 ← 000
21A-21B 0538-0539 ▀▀▄█ ▄ 6819 26649 V8 ← 025
21C-21D 0540-0541 ▄ █ █ 22A2 08866 Call show scoreNow is the starting loop of the game, which starts by showing the bomb count and ends the game if this is zero by calling the end routine:
21E-21F 0542-0543 ▄ █ ▄▄▀ 22AC 08876 start Call show count
220-221 0544-0545 ▀ ▀ 4800 18432 Skip next if V8 <> 000
222-223 0546-0547 ▄▄ █▄ ▀ 12D8 04824 Jump to endRegisters are initialized for displaying the bomb sprite below the submarine and storing the input flag:
224-225 0548-0549 ▀▀ ▄▀ █ 6509 25865 V5 ← 009
226-227 0550-0551 █▄▀▄ ▄█▄ A2D7 41687 I ← bomb
228-229 0552-0553 ▀▀ ▀▀ 6300 25344 V3 ← 000Then the input is tested for, setting a flag and displaying the bomb if so. It's noteworthy that this depends on both tests triggering for a single key press; a better way would have used only one test and collected the conditional code into a single segment:
22A-22B 0554-0555 ▀▀ ▀█ █ 6D05 27909 control VD ← 005
22C-22D 0556-0557 █▀█ ▀▀ █ EDA1 60833 Skip next if VD <> key
22E-22F 0558-0559 ▀▀ ▀█ 6301 25345 V3 ← 001
230-231 0560-0561 ▀▄ ▀▀▀ 8E40 36416 VE ← V4
232-233 0562-0563 █▀█ ▀▀ █ EDA1 60833 Skip next if VD <> key
234-235 0564-0565 ▀█ █▀▀▀▄ DE51 56913 Draw 08×01 at VE,V5; VF ← XOR
236-237 0566-0567 ▄█▄▄▀ 123C 04668 Jump to primeThese instructions are superfluous:
238-239 0568-0569 █▀█ ▀▀ █ EDA1 60833 skipped Skip next if VD <> key
23A-23B 0570-0571 ▄▄▀▄▄ ▀ 22D8 08920 also skipped Call endNow is the prime loop of the game, moving the player's submarine along first, with a superfluous jump instruction:
23C-23D 0572-0573 █▄▀▄ ▄▀ A2D4 41684 prime I ← you
23E-23F 0574-0575 ▀█▄▀ ▀▄▄ D463 54371 Draw 08×03 at V4,V6; VF ← XOR
240-241 0576-0577 ▄ ▀ █ 1242 04674 Jump to next
242-243 0578-0579 ▄███▄█▄▄ 74FF 29951 next V4 ← V4 + 255
244-245 0580-0581 ▀█▄▀ ▀▄▄ D463 54371 Draw 08×03 at V4,V6; VF ← XORNext the small enemy is moved a small and random amount to the right:
246-247 0582-0583 █▄▀▄ ▀ A2D0 41680 I ← small enemy
248-249 0584-0585 ██ ▀▀ █▀ DBC2 56258 Draw 08×02 at VB,VC; VF ← XOR
24A-24B 0586-0587 ▀▀ ▀█ ▀ CD04 52484 VD ← ??? AND 004
24C-24D 0588-0589 █▄ ▄▀▄▀▀ 8BD4 35796 VB ← VB + VD; VF ← overflow
24E-24F 0590-0591 ██ ▀▀ █▀ DBC2 56258 Draw 08×02 at VB,VC; VF ← XORIf the bomb has now struck the small enemy, the small hit routine is entered to adjust the score and whatnot. Note this is a simple check because of the differing verticals used for the enemies:
250-251 0592-0593 ▀▀▀▀▀▀ 3F00 16128 Skip next if VF = 000
252-253 0594-0595 ▄ █ █ 1292 04754 Jump to small hitNext the big enemy is moved a small and random amount, with a 1/8 chance of moving to the right and a 7/8 chance of moving to the left a larger amount:
254-255 0596-0597 █▄▀ ▄▄▀▄ A2CD 41677 I ← big enemy
256-257 0598-0599 █▀▄▀▀ ▄▀ D9A2 55714 Draw 08×02 at V9,VA; VF ← XOR
258-259 0600-0601 ▀▀ ▀█▄█ CD07 52487 VD ← ??? AND 007
25A-25B 0602-0603 ▀ ▀▀ ▀ 4D00 19712 Skip next if VD <> 000
25C-25D 0604-0605 ▀▀▀▀ ▄█ 7903 30979 V9 ← V9 + 003
25E-25F 0606-0607 ▄████▄ █ 79FD 31229 V9 ← V9 + 253
260-261 0608-0609 █▀▄▀▀ ▄▀ D9A2 55714 Draw 08×02 at V9,VA; VF ← XORThe collision detection is the same as for the small enemy, but transferring to a different hit routine:
262-263 0610-0611 ▀▀▀▀▀▀ 3F00 16128 Skip next if VF = 000
264-265 0612-0613 ▄ ▀▄▄▀ 128C 04748 Jump to big hitIf a bomb has not yet been dropped, then the player may still give a command to do so:
266-267 0614-0615 ▀ ▀▀ 4300 17152 Skip next if V3 <> 000
268-269 0616-0617 ▄▀▄ █ 122A 04650 Jump to controlIf a bomb is active, then its position is now adjusted at a constant rate and with sound lasting 1/60 of a second. When a bomb reaches the bottom of the screen, that means it's failed to hit any enemies and the count is then decreased:
26A-26B 0618-0619 █▄▀▄ ▄█▄ A2D7 41687 I ← bomb
26C-26D 0620-0621 ▀█ █▀▀▀▄ DE51 56913 Draw 08×01 at VE,V5; VF ← XOR
26E-26F 0622-0623 ▀ ▄▄█▄█ 451F 17695 Skip next if V5 <> 031
270-271 0624-0625 ▄ ▀ ▄█ 1286 04742 Jump to decrease
272-273 0626-0627 ▀▀▀ ▀▄▀ 7502 29954 V5 ← V5 + 002
274-275 0628-0629 ▀▀▀█▄ ▀▀ F318 62232 sound ← V3
276-277 0630-0631 ▀█ █▀▀▀▄ DE51 56913 Draw 08×01 at VE,V5; VF ← XORIf the bomb collides with an enemy now, then the prime routine is not entered. It's noteworthy that a test if not zero would be better here:
278-279 0632-0633 ▀▀▀▀▀█ 3F01 16129 Skip next if VF = 001
27A-27B 0634-0635 ▄█▄▄▀ 123C 04668 Jump to primeA collision has occured, and the vertical position is used to determine which enemy was struck:
27C-27D 0636-0637 ▀▀▄██▄█ 6D1F 27935 VD ← 031
27E-27F 0638-0639 ▀▄ ▄▀▀▄▀ 8D52 36178 VD ← VD AND V5
280-281 0640-0641 ▀ ▄██▄█ 4D1F 19743 Skip next if VD <> 031
282-283 0642-0643 ▄ ▀▄▄▀ 128C 04748 Jump to big hit
284-285 0644-0645 ▄ █ █ 1292 04754 Jump to small hitThe decrease routine erases the bomb count and decrements it before jumping to the starting loop:
286-287 0646-0647 ▄ █ ▄▄▀ 22AC 08876 decrease Call show count
288-289 0648-0649 ▄████▄▄▄ 78FF 30975 V8 ← V8 + 255
28A-28B 0650-0651 █▄▄█ 121E 04638 Jump to startThe big hit routine erases the score and increases it by five, before jumping to the shared routine:
28C-28D 0652-0653 ▄ █ █ 22A2 08866 big hit Call show score
28E-28F 0654-0655 ▀▀▀ █▀█ 7705 30469 V7 ← V7 + 005
290-291 0656-0657 ▄ █ ▄█ 1296 04758 Jump to sharedThe small hit routine erases the score and increases it by ten, falling into the shared routine. The shared routine shows the updated score, plays a sound lasting 1/20 of a second, erases the bomb, and then jumps to the decrease routine:
292-293 0658-0659 ▄ █ █ 22A2 08866 small hit Call show score
294-295 0660-0661 ▀▀▀▄▀█▀ 770A 30474 V7 ← V7 + 010
296-297 0662-0663 ▄ █ █ 22A2 08866 shared Call show score
298-299 0664-0665 ▀▀ ▀▀▄█ 6D03 27907 VD ← 003
29A-29B 0666-0667 ▀▀▀██▀ ▀ FD18 64792 sound ← VD
29C-29D 0668-0669 █▄▀▄ ▄█▄ A2D7 41687 I ← bomb
29E-29F 0670-0671 ▀█ █▀▀▀▄ DE51 56913 Draw 08×01 at VE,V5; VF ← XOR
2A0-2A1 0672-0673 ▄ ▀ ▄█ 1286 04742 Jump to decreaseThe show score routine writes the score to the scratch location, adjusts register three, and calls the show routine before returning:
2A2-2A3 0674-0675 █▄█▄▄ ▀ A2F8 41720 show score I ← scratch
2A4-2A5 0676-0677 ▀▀██ ▀██ F733 63283 V7 as BCD stored from I
2A6-2A7 0678-0679 ▀▀ ▀▀ 6300 25344 V3 ← 000
2A8-2A9 0680-0681 ▄ █▄ ▄█ 22B6 08886 Call show
2AA-2AB 0682-0683 ▄▄▄ ▄▄▄ 00EE 00238 ReturnThe show count routine writes the count to the scratch location, adjusts register three, and calls the show routine before returning:
2AC-2AD 0684-0685 █▄█▄▄ ▀ A2F8 41720 show count I ← scratch
2AE-2AF 0686-0687 ▀▀██▀ ▄▄ F833 63539 V8 as BCD stored from I
2B0-2B1 0688-0689 ▀█▄ █▀ 6332 25394 V3 ← 050
2B2-2B3 0690-0691 ▄ █▄ ▄█ 22B6 08886 Call show
2B4-2B5 0692-0693 ▄▄▄ ▄▄▄ 00EE 00238 ReturnThe show routine draws a basic three digit number at a constant vertical with a variable horizontal position before returning:
2B6-2B7 0694-0695 ▀▀ ▀▀ ▀ 6D00 27904 show VD ← 000
2B8-2B9 0696-0697 ▀██▀ ▄▀▄ F265 62053 Load V0→V2; I ← I + 03
2BA-2BB 0698-0699 ▀▀█▀▄ ▄ F029 61481 I ← digit sprite of V0
2BC-2BD 0700-0701 ██ █ ▄▀█ D3D5 54229 Draw 08×05 at V3,VD; VF ← XOR
2BE-2BF 0702-0703 ▀▀▀ ▄▀█ 7305 29445 V3 ← V3 + 005
2C0-2C1 0704-0705 ▀▀█▀▄ █ F129 61737 I ← digit sprite of V1
2C2-2C3 0706-0707 ██ █ ▄▀█ D3D5 54229 Draw 08×05 at V3,VD; VF ← XOR
2C4-2C5 0708-0709 ▀▀▀ ▄▀█ 7305 29445 V3 ← V3 + 005
2C6-2C7 0710-0711 ▀▀█▀▄ ▀▄ F229 61993 I ← digit sprite of V2
2C8-2C9 0712-0713 ██ █ ▄▀█ D3D5 54229 Draw 08×05 at V3,VD; VF ← XOR
2CA-2CB 0714-0715 ▄▄▄ ▄▄▄ 00EE 00238 ReturnFollowing that are the sprites used by the game and some waste:
2CC 0716 █ 01 001
2CD 0717 █ 08 008 big enemy
2CE 0718 ███████ 7F 127
2CF 0719 █████ 7C 124
2D0 0720 █ 08 008 small enemy
2D1 0721 █████ 3E 062
2D2 0722 ██ 60 096
2D3 0723 █ 08 008
2D4 0724 ██ 18 024 you
2D5 0725 ████ 3C 060
2D6 0726 ████████ FF 255
2D7 0727 █ 08 008 bombThe end routine displays the go, od, by, and e! sprites before entering an infinite loop to end the game:
2D8-2D9 0728-0729 ▀ ▀ ▀▀ A300 41728 end I ← go
2DA-2DB 0730-0731 ▀▀▄ ▀█ 6311 25361 V3 ← 017
2DC-2DD 0732-0733 ▀▀ █▀▄█ 6D0B 27915 VD ← 011
2DE-2DF 0734-0735 ██ █ ▄▀█ D3D5 54229 Draw 08×05 at V3,VD; VF ← XOR
2E0-2E1 0736-0737 ▀ ▀ ▄▀█ A305 41733 I ← od
2E2-2E3 0738-0739 ▀▀▄▄ ▀█ 6319 25369 V3 ← 025
2E4-2E5 0740-0741 ██ █ ▄▀█ D3D5 54229 Draw 08×05 at V3,VD; VF ← XOR
2E6-2E7 0742-0743 ▀ ▀ ▄ █▀ A30A 41738 I ← by
2E8-2E9 0744-0745 ▀█ ██ 6323 25379 V3 ← 035
2EA-2EB 0746-0747 ██ █ ▄▀█ D3D5 54229 Draw 08×05 at V3,VD; VF ← XOR
2EC-2ED 0748-0749 ▀ ▀ ▄▄██ A30F 41743 I ← e!
2EE-2EF 0750-0751 ▀█ ▄ ██ 632B 25387 V3 ← 043
2F0-2F1 0752-0753 ██ █ ▄▀█ D3D5 54229 Draw 08×05 at V3,VD; VF ← XOR
2F2-2F3 0754-0755 ▀▀ ▀▀ 6300 25344 V3 ← 000
2F4-2F5 0756-0757 ▄▄▄█ ▄▀ 12F4 04852 self Jump to selfFollowing that is the scratch location and waste:
2F6 0758 ██ ██ █ 6D 109
2F7 0759 █ ██ 0B 011
2F8 0760 00 000 scratch
2F9 0761 █ 01 001
2FA 0762 █ 04 004
2FB 0763 00 000
2FC 0764 00 000
2FD 0765 ███ ███ EE 238
2FE 0766 00 000
2FF 0767 █ 01 001Following yet that are the sprites used for displaying the ending message:
300 0768 ███ ███ EE 238 go
301 0769 █ █ █ 8A 138
302 0770 █ █ █ 8A 138
303 0771 █ █ █ █ AA 170
304 0772 ███ ███ EE 238
305 0773 ███ ████ EF 239 od
306 0774 █ █ █ █ A5 165
307 0775 █ █ █ █ A5 165
308 0776 █ █ █ █ A5 165
309 0777 ███ ████ EF 239
30A 0778 ████ █ 7A 122 by
30B 0779 █ █ █ 2A 042
30C 0780 ███ ██ 3B 059
30D 0781 █ █ █ 29 041
30E 0782 ████ █ 79 121
30F 0783 █ ███ █ BA 186 e!
310 0784 █ █ █ A2 162
311 0785 █ ██ █ B2 178
312 0786 █ 20 032
313 0787 ███ █ 3A 058The game ends with more waste:
314 0788 ██ █ 34 052
315 0789 ███ █ 3A 058
316 0790 ████ 3C 060
317 0791 ██ █ ██ D6 214
318 0792 █ █ █ 54 084
319 0793 ███ 1C 028
31A 0794 ██ 0C 012
31B 0795 █ 40 064
31C 0796 █ ████ 9E 158
31D 0797 █ █ █ 25 037
31E 0798 ██ █ 68 104
31F 0799 ██ 0C 012