A Documenting of mine Advanced Asphyxiation CHIP-8 Game This is documentation for the Advanced Asphyxiation CHIP-8 game, a rewriting and improvement of what I wrote earlier. This is more faithful to the original game, truly being a game, but lacks enemies. Follows is the program as displayed in mine MMC, how I see it as I wrote it: 200-201 0512-0513 ▄▄▄▄▄▄▄▄ 00FF 00255  Enable extended mode 202-203 0514-0515 █▄█▄ ▀▀▀ A7F0 42992  I ← 2032 204-205 0516-0517 ▀██▀▀█▀█ FF65 65381  Load V0→VF; I ← I + 16 206-207 0518-0519  ▀▀ ▄▀█▀ 670A 26378  V7 ← 010 208-209 0520-0521 ▄██▄█▄▄█ 69FF 27135  V9 ← 255 20A-20B 0522-0523 ▀ ▀▄▄ ▀ A218 41496  I ← player 20C-20D 0524-0525 █▀▄█▀ ▀▄ DAB1 55985  Draw 08×01 at VA,VB; VF ← XOR 20E-20F 0526-0527 ▀▀ ▀▀▀▄ CE01 52737 maze VE ← ??? AND 001 210-211 0528-0529  ▀▀ ▀▀ ▀ 6D00 27904  VD ← 000 212-213 0530-0531 ▀▄▀ ▄▄█▀ A34E 41806 maze step I ← backstage 214-215 0532-0533 ▀▀▀███▄▀ FD1E 64798  I ← I + VD 216-217 0534-0535 ▀██▀ ▄▀█ F365 62309  Load V0→V3; I ← I + 04 218-219 0536-0537 ▀ ▄▄▄ 800E 32782 player V0 ← V0 × 2; VF ← MSB 21A-21B 0538-0539 █▄▄▄▄█▄ 84FE 34046  V4 ← VF × 2; VF ← MSB 21C-21D 0540-0541 ▀ ▄▄▄▄▀ 811E 33054  V1 ← V1 × 2; VF ← MSB 21E-21F 0542-0543 █▄▄▄ ▀ ▄ 84F1 34033  V4 ← V4 OR VF 220-221 0544-0545 █▄▄ ▄█▄▀ 85EE 34286  V5 ← VE × 2; VF ← MSB 222-223 0546-0547 ▀ ▄ ▄▄█ 822E 33326  V2 ← V2 × 2; VF ← MSB 224-225 0548-0549 █▄▄▄▀▀▀ 8EF0 36592  VE ← VF 226-227 0550-0551 █▄▄▄ ▀ █ 85F1 34289  V5 ← V5 OR VF 228-229 0552-0553 ▀▄ ▄▄█▄▀ 855E 34142  V5 ← V5 × 2; VF ← MSB 22A-22B 0554-0555 ▀ ▄▄▄▄█▀ 833E 33598  V3 ← V3 × 2; VF ← MSB 22C-22D 0556-0557 █▄▄▄ ▀ █ 85F1 34289  V5 ← V5 OR VF 22E-22F 0558-0559 ▀ █▄▄▄█▀ A33E 41790  I ← random 230-231 0560-0561 ▀▀▀█▄█▄ F41E 62494  I ← I + V4 232-233 0562-0563 ▀██▀ ▄ ▄ F065 61541  Load V0→V0; I ← I + 01 234-235 0564-0565  █ █▀ 2322 08994  Call shift 236-237 0566-0567 █▄▄▄ ▀ 82F0 33520  V2 ← VF 238-239 0568-0569 ▀▄▀ █▀ A342 41794  I ← drunk 23A-23B 0570-0571 ▀▀▀█▄█▄ F41E 62494  I ← I + V4 23C-23D 0572-0573 ▀██▀ ▄ ▄ F065 61541  Load V0→V0; I ← I + 01 23E-23F 0574-0575  █ █▀ 2322 08994  Call shift 240-241 0576-0577  ▀▀ ▀ 3200 12800  Skip next if V2 = 000 242-243 0578-0579 ▀▀ ▀▀▀█ CF01 52993  VF ← ??? AND 001 244-245 0580-0581  ▀▀ 6000 24576  V0 ← 000 246-247 0582-0583  ▀▀▀▀▀▀ 3F00 16128  Skip next if VF = 000 248-249 0584-0585 ▄██▄ 60F0 24816  V0 ← 240 24A-24B 0586-0587 ▀▄▀▄ ▀▀ A350 41808  I ← stage 24C-24D 0588-0589 ▀▀▀███▄▀ FD1E 64798  I ← I + VD 24E-24F 0590-0591 ▀█▀█ ▄ ▄ F055 61525  Save V0→V0; I ← I + 01 250-251 0592-0593  ▀▀▀▀▀ █ 7D01 32001  VD ← VD + 001 252-253 0594-0595  ▀█▀▀ ▀ 3D10 15632  Skip next if VD = 016 254-255 0596-0597  ▄▄▀ ▄▀ 1264 04708  Jump to draw curtains 256-257 0598-0599 ▀▄█▄ ▀▀ A370 41840  I ← wardrobe 258-259 0600-0601 ▀█▀█▀█▀█ FF55 65365  Save V0→VF; I ← I + 16 25A-25B 0602-0603 ▀▄▀▄ ▀▀ A350 41808  I ← stage 25C-25D 0604-0605 ▀██▀▀█▀█ FF65 65381  Load V0→VF; I ← I + 16 25E-25F 0606-0607 ▀█▀█▀█▀█ FF55 65365  Save V0→VF; I ← I + 16 260-261 0608-0609 ▀▄█▄ ▀▀ A370 41840  I ← wardrobe 262-263 0610-0611 ▀██▀▀█▀█ FF65 65381  Load V0→VF; I ← I + 16 264-265 0612-0613  ▀▀▀▀▀ ▄ 7C01 31745 draw curtains VC ← VC + 001 266-267 0614-0615  ▀ ▀█ 4C04 19460  Skip next if VC <> 004 268-269 0616-0617  ▀▀ ▀▀ 6C00 27648  VC ← 000 26A-26B 0618-0619  ▀▀▀▀ 3C00 15360  Skip next if VC = 000 26C-26D 0620-0621 ▄ ▀▄▄█ 128E 04750  Jump to move 26E-26F 0622-0623 ▀▄█ ▀▀ A360 41824  I ← fourth wall 270-271 0624-0625 ▄▄ ▄ 00C1 00193  Scroll ↓ by 01 272-273 0626-0627  ▀▀ ▀ 6100 24832  V1 ← 000 274-275 0628-0629  ██▄▄▄▀ 627C 25212  V2 ← 124 276-277 0630-0631  ▀▀▀▀ ▀█ 7B01 31489  VB ← VB + 001 278-279 0632-0633 ▄▄███▄▄█ 39FF 14847  Skip next if V9 = 255 27A-27B 0634-0635  ▀▀▀▀ █ 7901 30977  V9 ← V9 + 001 27C-27D 0636-0637  █ ▀ ▀ 4940 18752  Skip next if V9 <> 064 27E-27F 0638-0639 ▄██▄█▄▄█ 69FF 27135  V9 ← 255 280-281 0640-0641 ██ ▀ █ D1C1 53697 show time Draw 08×01 at V1,VC; VF ← XOR 282-283 0642-0643 ██ ▀ ▀▄ D2C1 53953  Draw 08×01 at V2,VC; VF ← XOR 284-285 0644-0645 ▀██▀ ▄ ▄ F065 61541  Load V0→V0; I ← I + 01 286-287 0646-0647  ▀▀▀ ▄ ▀ 7104 28932  V1 ← V1 + 004 288-289 0648-0649 ▄███▄▄▀ 72FC 29436  V2 ← V2 + 252 28A-28B 0650-0651  ▄▀▀ ▀ 3140 12608  Skip next if V1 = 064 28C-28D 0652-0653 ▄ ▀ ▀ 1280 04736  Jump to show time 28E-28F 0654-0655 ▄▄███▄▄█ 39FF 14847 move Skip next if V9 = 255 290-291 0656-0657 ▄ ▄▀ ▄█ 12A6 04774  Jump to continue 292-293 0658-0659  ▀▀▀▀ 3C00 15360  Skip next if VC = 000 294-295 0660-0661 ▄ ▄▀ ▄█ 12A6 04774  Jump to continue 296-297 0662-0663 ▀ ▀▄▄ ▀ A218 41496  I ← player 298-299 0664-0665 ▀█▄▄█▄▄▄ C87F 51327  V8 ← ??? AND 127 29A-29B 0666-0667  ▀▀ ▀ █ 6901 26881  V9 ← 001 29C-29D 0668-0669 █▀ █▀ ▄ D891 55441  Draw 08×01 at V8,V9; VF ← XOR 29E-29F 0670-0671  ▀ ▀▀▀▀ 4F00 20224  Skip next if VF <> 000 2A0-2A1 0672-0673 ▄ ▄▀ ▄█ 12A6 04774  Jump to continue 2A2-2A3 0674-0675 █▀ █▀ ▄ D891 55441  Draw 08×01 at V8,V9; VF ← XOR 2A4-2A5 0676-0677 ▄██▄█▄▄█ 69FF 27135  V9 ← 255 2A6-2A7 0678-0679 ▀▄▀ ▄█▀ A346 41798 continue I ← from 2A8-2A9 0680-0681 ▀██▀ █▀▄ F665 63077  Load V0→V6; I ← I + 07 2AA-2AB 0682-0683  █ ▀ ▀▀ 4B40 19264  Skip next if VB <> 064 2AC-2AD 0684-0685  ▀ ▀ 1200 04608  Jump to 0512 2AE-2AF 0686-0687 █▀▀▄▄▄▄ E09E 57502 down Skip next if V0 = key 2B0-2B1 0688-0689 ▄ ▄█▄ ▀ 12B8 04792  Jump to left 2B2-2B3 0690-0691  ▀▄▄█▄██ 4B3F 19263  Skip next if VB <> 063 2B4-2B5 0692-0693 ▄ ▄█▄ ▀ 12B8 04792  Jump to left 2B6-2B7 0694-0695  ▀▀ ▀▀▄ 6601 26113  V6 ← 001 2B8-2B9 0696-0697 █▀▀▄▄▄▄▀ E19E 57758 left Skip next if V1 = key 2BA-2BB 0698-0699 ▄▄ ▀ █ 12C2 04802  Jump to right 2BC-2BD 0700-0701  ▀ ▀ ▀ 4A00 18944  Skip next if VA <> 000 2BE-2BF 0702-0703 ▄▄ ▀ █ 12C2 04802  Jump to right 2C0-2C1 0704-0705 ▄██▄▄█▄█ 65FF 26111  V5 ← 255 2C2-2C3 0706-0707 █▀▀▄▄▄█ E29E 58014 right Skip next if V2 = key 2C4-2C5 0708-0709 ▄▄ ▀▄▄▀ 12CC 04812  Jump to up 2C6-2C7 0710-0711  █▄▄█▄█▄ 4A7F 19071  Skip next if VA <> 127 2C8-2C9 0712-0713 ▄▄ ▀▄▄▀ 12CC 04812  Jump to up 2CA-2CB 0714-0715  ▀▀ ▀ █ 6501 25857  V5 ← 001 2CC-2CD 0716-0717 █▀▀▄▄▄█▀ E39E 58270 up Skip next if V3 = key 2CE-2CF 0718-0719 ▄▄ █ ▄█ 12D6 04822  Jump to resolve 2D0-2D1 0720-0721  ▀ ▀ ▀▀ 4B00 19200  Skip next if VB <> 000 2D2-2D3 0722-0723 ▄▄ █ ▄█ 12D6 04822  Jump to resolve 2D4-2D5 0724-0725 ▄██▄▄██▄ 66FF 26367  V6 ← 255 2D6-2D7 0726-0727 ▀ ▀▄▄ ▀ A218 41496 resolve I ← player 2D8-2D9 0728-0729 █▀ █▀ ▄ D891 55441  Draw 08×01 at V8,V9; VF ← XOR 2DA-2DB 0730-0731  ▀ ▀▀▀▀ 4F00 20224  Skip next if VF <> 000 2DC-2DD 0732-0733 █▀ █▀ ▄ D891 55441  Draw 08×01 at V8,V9; VF ← XOR 2DE-2DF 0734-0735 █▀▄█▀ ▀▄ DAB1 55985  Draw 08×01 at VA,VB; VF ← XOR 2E0-2E1 0736-0737 ▀▄ ▄▀▄▀ 8A54 35412  VA ← VA + V5; VF ← overflow 2E2-2E3 0738-0739 ▀▄▄ ▀▄▀▀ 8B64 35684  VB ← VB + V6; VF ← overflow 2E4-2E5 0740-0741 █▀▄█▀ ▀▄ DAB1 55985  Draw 08×01 at VA,VB; VF ← XOR 2E6-2E7 0742-0743 ▄▀▄▀▀ 58A0 22688  Skip next if V8 = VA 2E8-2E9 0744-0745 ▄▄▄█ █ 12F2 04850  Jump to next 2EA-2EB 0746-0747 ▄▀▄█▀ ▀ 59B0 22960  Skip next if V9 = VB 2EC-2ED 0748-0749 ▄▄▄█ █ 12F2 04850  Jump to next 2EE-2EF 0750-0751 ▄██▄█▄▄█ 69FF 27135  V9 ← 255 2F0-2F1 0752-0753  ▀▀▀ ▀▀█ 7701 30465  V7 ← V7 + 001 2F2-2F3 0754-0755  ▀ ▀▀▀▀ 4F00 20224 next Skip next if VF <> 000 2F4-2F5 0756-0757 ▄▄▄█▄▄█ 12FE 04862  Jump to break? 2F6-2F7 0758-0759 █▀▄█▀ ▀▄ DAB1 55985  Draw 08×01 at VA,VB; VF ← XOR 2F8-2F9 0760-0761 ▀▄ ▄▀▄▀▄ 8A55 35413  VA ← VA − V5; VF ← borrow 2FA-2FB 0762-0763 ▀▄▄ ▀▄▀█ 8B65 35685  VB ← VB − V6; VF ← borrow 2FC-2FD 0764-0765 █▀▄█▀ ▀▄ DAB1 55985  Draw 08×01 at VA,VB; VF ← XOR 2FE-2FF 0766-0767 █▀▀▄▄█▄ E49E 58526 break? Skip next if V4 = key 300-301 0768-0769  █ ▄▀▀ 1314 04884  Jump to exhaust delay 302-303 0770-0771  ▀ ▀▀▀ 4700 18176  Skip next if V7 <> 000 304-305 0772-0773  █ ▄▀▀ 1314 04884  Jump to exhaust delay 306-307 0774-0775 ▀ █▄▄ █▀ A33A 41786  I ← make break 308-309 0776-0777 █ ▄ 80A0 32928  V0 ← VA 30A-30B 0778-0779 █ ▄▄ ▀ 81B0 33200  V1 ← VB 30C-30D 0780-0781 ▄███▄▄▄▄ 70FF 28927  V0 ← V0 + 255 30E-30F 0782-0783 ▄███▄▄ ▀ 71FC 29180  V1 ← V1 + 252 310-311 0784-0785 ▄███▄███ 77FF 30719  V7 ← V7 + 255 312-313 0786-0787 ▀▀ █ ▄ D014 53268  Draw 08×04 at V0,V1; VF ← XOR 314-315 0788-0789 ▀▀▀▀▀███ FF07 65287 exhaust delay VF ← delay 316-317 0790-0791  ▀▀▀▀▀▀ 3F00 16128  Skip next if VF = 000 318-319 0792-0793  █ ▄▀▀ 1314 04884  Jump to exhaust delay 31A-31B 0794-0795 ▀▀▀█ ▄▀▄ F215 61973  delay ← V2 31C-31D 0796-0797  ▀█▀▀ ▀ 3D10 15632  Skip next if VD = 016 31E-31F 0798-0799  █ █ 1212 04626  Jump to maze step 320-321 0800-0801  ▀▄▄█ 120E 04622  Jump to maze 322-323 0802-0803 ▀ ▀ 8100 33024 shift V1 ← V0 324-325 0804-0805 ▀▄ ▄▄▄▄ 805E 32862  V0 ← V5 × 2; VF ← MSB 326-327 0806-0807 ▀ █▀▄ ▀▀ B328 45864  Jump to V0 + table 328-329 0808-0809 ▀ ▄ ▄▄▀ 8116 33046 table V1 ← V1 ÷ 2; VF ← LSB 32A-32B 0810-0811 ▀ ▄ ▄▄▀ 8116 33046  V1 ← V1 ÷ 2; VF ← LSB 32C-32D 0812-0813 ▀ ▄ ▄▄▀ 8116 33046  V1 ← V1 ÷ 2; VF ← LSB 32E-32F 0814-0815 ▀ ▄ ▄▄▀ 8116 33046  V1 ← V1 ÷ 2; VF ← LSB 330-331 0816-0817 ▀ ▄ ▄▄▀ 8116 33046  V1 ← V1 ÷ 2; VF ← LSB 332-333 0818-0819 ▀ ▄ ▄▄▀ 8116 33046  V1 ← V1 ÷ 2; VF ← LSB 334-335 0820-0821 ▀ ▄ ▄▄▀ 8116 33046  V1 ← V1 ÷ 2; VF ← LSB 336-337 0822-0823 ▀ ▄ ▄▄▀ 8116 33046  V1 ← V1 ÷ 2; VF ← LSB 338-339 0824-0825 ▄▄▄ ▄▄▄ 00EE 00238  Return 33A-33B 0826-0827 ████ F0F0 61680 make break 33C-33D 0828-0829 ████ F0F0 61680  33E-33F 0830-0831  ▀▄ ▀▀ 1308 04872 random 340-341 0832-0833 ▄ █▄ 1098 04248  342-343 0834-0835 ███▄ E0F0 57584 drunk 344-345 0836-0837 ▀▀█ E020 57376  346 0838  █ 02 002 from 347 0839  █ 04 004  348 0840  ██ 06 006  349 0841  █ 08 008  34A-34B 0842-0843  0000 00000  34C-34D 0844-0845  0000 00000  34E-34F 0846-0847 ▀▀▀▀ F000 61440 backstage 350-351 0848-0849  0000 00000 stage 352-353 0850-0851  0000 00000  354-355 0852-0853  0000 00000  356-357 0854-0855  0000 00000  358-359 0856-0857  0000 00000  35A-35B 0858-0859  0000 00000  35C-35D 0860-0861  0000 00000  35E-35F 0862-0863  0000 00000  360-361 0864-0865  0000 00000 fourth wall 362-363 0866-0867  0000 00000  364-365 0868-0869  0000 00000  366-367 0870-0871  0000 00000  368-369 0872-0873  0000 00000  36A-36B 0874-0875  0000 00000  36C-36D 0876-0877  0000 00000  36E-36F 0878-0879  0000 00000  370-371 0880-0881  0000 00000 wardrobe The register usage is as follows: V0 Hold cells for the automaton; hold a key code; and hold the argument to a subroutine. V1 Hold a cell for the automaton; hold the horizontal coordinate of part of the maze drawing; hold a key code; and operate as a temporary register. V2 Hold a cell for the automaton; hold the horizontal coordinate of part of the maze drawing; hold a key code; operate as a temporary register; and manipulate the delay register. V3 Hold a cell for the automaton; and hold a key code. V4 Hold a generated index for the maze generation; and hold a key code. V5 Hold a generated index for the maze generation; and hold a movement delta. V6 Hold a movement delta. V7 Store the make break count. V8 Hold the horizontal coordinate of the make break. V9 Hold the vertical coordinate and presence sigil of the make break. VA Hold the horizontal coordinate of the player. VB Hold the vertical coordinate of the player. VC Hold a rotating counter and the vertical coordinate of part of the maze drawing. VD Hold the current cell index of the maze generation. VE Hold a prior cell state for the automaton. VF Hold the result of a subroutine; manipulate the delay register; indicate collisions, and whatnot. More care was taken in register selection with this iteration; in particular, it was recognized that the first many registers had no persistent state after the automaton stepping, and so could be used, without issue. Unfortunately, I resisted using entirely disparate register banks in this; it caused issues with register exhaustion that could've been avoided. The register manipulation of the latter half of the game is sloppy, in mine eyes, and this game would benefit from heavier rewriting, later. The game begins by entering Super CHIP-8 mode, clearing all registers to zero, initializing the make break count, configuring the make break sigil to indicate no presence, and then drawing that player: 200-201 0512-0513 ▄▄▄▄▄▄▄▄ 00FF 00255  Enable extended mode 202-203 0514-0515 █▄█▄ ▀▀▀ A7F0 42992  I ← 2032 204-205 0516-0517 ▀██▀▀█▀█ FF65 65381  Load V0→VF; I ← I + 16 206-207 0518-0519  ▀▀ ▄▀█▀ 670A 26378  V7 ← 010 208-209 0520-0521 ▄██▄█▄▄█ 69FF 27135  V9 ← 255 20A-20B 0522-0523 ▀ ▀▄▄ ▀ A218 41496  I ← player 20C-20D 0524-0525 █▀▄█▀ ▀▄ DAB1 55985  Draw 08×01 at VA,VB; VF ← XOR Unlike that prior implementation, a more consistent framerate is achieved by generating each cell of the automaton in step with the rest of the game, rather than all at once; the paper I read indicated a random initial value for part of the algorithm, which corresponds to the CE01. Rather than move I by FX65, I use labels offset appropriately; this implementation avoids a mask by using 8XYE instead. Each value is either zero or two hundred and forty, as but two symbols are needed, and these exactly match the sprites used in drawing. Indices into the bit tables drunk and random are built as shown: 20E-20F 0526-0527 ▀▀ ▀▀▀▄ CE01 52737 maze VE ← ??? AND 001 210-211 0528-0529  ▀▀ ▀▀ ▀ 6D00 27904  VD ← 000 212-213 0530-0531 ▀▄▀ ▄▄█▀ A34E 41806 maze step I ← backstage 214-215 0532-0533 ▀▀▀███▄▀ FD1E 64798  I ← I + VD 216-217 0534-0535 ▀██▀ ▄▀█ F365 62309  Load V0→V3; I ← I + 04 218-219 0536-0537 ▀ ▄▄▄ 800E 32782 player V0 ← V0 × 2; VF ← MSB 21A-21B 0538-0539 █▄▄▄▄█▄ 84FE 34046  V4 ← VF × 2; VF ← MSB 21C-21D 0540-0541 ▀ ▄▄▄▄▀ 811E 33054  V1 ← V1 × 2; VF ← MSB 21E-21F 0542-0543 █▄▄▄ ▀ ▄ 84F1 34033  V4 ← V4 OR VF 220-221 0544-0545 █▄▄ ▄█▄▀ 85EE 34286  V5 ← VE × 2; VF ← MSB 222-223 0546-0547 ▀ ▄ ▄▄█ 822E 33326  V2 ← V2 × 2; VF ← MSB 224-225 0548-0549 █▄▄▄▀▀▀ 8EF0 36592  VE ← VF 226-227 0550-0551 █▄▄▄ ▀ █ 85F1 34289  V5 ← V5 OR VF 228-229 0552-0553 ▀▄ ▄▄█▄▀ 855E 34142  V5 ← V5 × 2; VF ← MSB 22A-22B 0554-0555 ▀ ▄▄▄▄█▀ 833E 33598  V3 ← V3 × 2; VF ← MSB 22C-22D 0556-0557 █▄▄▄ ▀ █ 85F1 34289  V5 ← V5 OR VF Again for a more consistent framerate, both random and drunk are indexed, regardless of the value in random. The shift routine is used to extract the particular bit. I was unable to avoid conditional code in setting the new cell value, but did nicely avoid unnecessary register movement in how random values are set, by conditionally manipulating the apparent value of that drunk bit. I would've been able to unconditionally map one to two hundred and forty, but lacked a multiplication sled I needed: 22E-22F 0558-0559 ▀ █▄▄▄█▀ A33E 41790  I ← random 230-231 0560-0561 ▀▀▀█▄█▄ F41E 62494  I ← I + V4 232-233 0562-0563 ▀██▀ ▄ ▄ F065 61541  Load V0→V0; I ← I + 01 234-235 0564-0565  █ █▀ 2322 08994  Call shift 236-237 0566-0567 █▄▄▄ ▀ 82F0 33520  V2 ← VF 238-239 0568-0569 ▀▄▀ █▀ A342 41794  I ← drunk 23A-23B 0570-0571 ▀▀▀█▄█▄ F41E 62494  I ← I + V4 23C-23D 0572-0573 ▀██▀ ▄ ▄ F065 61541  Load V0→V0; I ← I + 01 23E-23F 0574-0575  █ █▀ 2322 08994  Call shift 240-241 0576-0577  ▀▀ ▀ 3200 12800  Skip next if V2 = 000 242-243 0578-0579 ▀▀ ▀▀▀█ CF01 52993  VF ← ??? AND 001 244-245 0580-0581  ▀▀ 6000 24576  V0 ← 000 246-247 0582-0583  ▀▀▀▀▀▀ 3F00 16128  Skip next if VF = 000 248-249 0584-0585 ▄██▄ 60F0 24816  V0 ← 240 The stage is set and, once that automaton is finished with the next generation, those new values are nicely set by using all sixteen registers; the fourth wall indicating the actual maze is immediately following stage, enabling this nice trick. The wardrobe is but temporary storage for all registers: 24A-24B 0586-0587 ▀▄▀▄ ▀▀ A350 41808  I ← stage 24C-24D 0588-0589 ▀▀▀███▄▀ FD1E 64798  I ← I + VD 24E-24F 0590-0591 ▀█▀█ ▄ ▄ F055 61525  Save V0→V0; I ← I + 01 250-251 0592-0593  ▀▀▀▀▀ █ 7D01 32001  VD ← VD + 001 252-253 0594-0595  ▀█▀▀ ▀ 3D10 15632  Skip next if VD = 016 254-255 0596-0597  ▄▄▀ ▄▀ 1264 04708  Jump to draw curtains 256-257 0598-0599 ▀▄█▄ ▀▀ A370 41840  I ← wardrobe 258-259 0600-0601 ▀█▀█▀█▀█ FF55 65365  Save V0→VF; I ← I + 16 25A-25B 0602-0603 ▀▄▀▄ ▀▀ A350 41808  I ← stage 25C-25D 0604-0605 ▀██▀▀█▀█ FF65 65381  Load V0→VF; I ← I + 16 25E-25F 0606-0607 ▀█▀█▀█▀█ FF55 65365  Save V0→VF; I ← I + 16 260-261 0608-0609 ▀▄█▄ ▀▀ A370 41840  I ← wardrobe 262-263 0610-0611 ▀██▀▀█▀█ FF65 65381  Load V0→VF; I ← I + 16 Rows of the maze are drawn once every four cycles, which matches perfectly with the sixteen cells of the automaton. The screen is scrolled, coordinates for the player and make break are incremented if necessary, and the make break is reset if past the end. If not that, the move segment is jumped to: 264-265 0612-0613  ▀▀▀▀▀ ▄ 7C01 31745 draw curtains VC ← VC + 001 266-267 0614-0615  ▀ ▀█ 4C04 19460  Skip next if VC <> 004 268-269 0616-0617  ▀▀ ▀▀ 6C00 27648  VC ← 000 26A-26B 0618-0619  ▀▀▀▀ 3C00 15360  Skip next if VC = 000 26C-26D 0620-0621 ▄ ▀▄▄█ 128E 04750  Jump to move 26E-26F 0622-0623 ▀▄█ ▀▀ A360 41824  I ← fourth wall 270-271 0624-0625 ▄▄ ▄ 00C1 00193  Scroll ↓ by 01 272-273 0626-0627  ▀▀ ▀ 6100 24832  V1 ← 000 274-275 0628-0629  ██▄▄▄▀ 627C 25212  V2 ← 124 276-277 0630-0631  ▀▀▀▀ ▀█ 7B01 31489  VB ← VB + 001 278-279 0632-0633 ▄▄███▄▄█ 39FF 14847  Skip next if V9 = 255 27A-27B 0634-0635  ▀▀▀▀ █ 7901 30977  V9 ← V9 + 001 27C-27D 0636-0637  █ ▀ ▀ 4940 18752  Skip next if V9 <> 064 27E-27F 0638-0639 ▄██▄█▄▄█ 69FF 27135  V9 ← 255 The show time routine draws one row of the maze. As VC is zero to enter this routine, it can safely be used for the vertical coordinate. As I only progresses one way, the row is drawn towards center: 280-281 0640-0641 ██ ▀ █ D1C1 53697 show time Draw 08×01 at V1,VC; VF ← XOR 282-283 0642-0643 ██ ▀ ▀▄ D2C1 53953  Draw 08×01 at V2,VC; VF ← XOR 284-285 0644-0645 ▀██▀ ▄ ▄ F065 61541  Load V0→V0; I ← I + 01 286-287 0646-0647  ▀▀▀ ▄ ▀ 7104 28932  V1 ← V1 + 004 288-289 0648-0649 ▄███▄▄▀ 72FC 29436  V2 ← V2 + 252 28A-28B 0650-0651  ▄▀▀ ▀ 3140 12608  Skip next if V1 = 064 28C-28D 0652-0653 ▄ ▀ ▀ 1280 04736  Jump to show time The move routine begins by calculating the make break, if necessary. The make break is only changed if not already active and only then once every four cycles. It's opportunistically drawn at the top of the screen, bailing out and correcting the maze if it collides with a wall to try the next cycle: 28E-28F 0654-0655 ▄▄███▄▄█ 39FF 14847 move Skip next if V9 = 255 290-291 0656-0657 ▄ ▄▀ ▄█ 12A6 04774  Jump to continue 292-293 0658-0659  ▀▀▀▀ 3C00 15360  Skip next if VC = 000 294-295 0660-0661 ▄ ▄▀ ▄█ 12A6 04774  Jump to continue 296-297 0662-0663 ▀ ▀▄▄ ▀ A218 41496  I ← player 298-299 0664-0665 ▀█▄▄█▄▄▄ C87F 51327  V8 ← ??? AND 127 29A-29B 0666-0667  ▀▀ ▀ █ 6901 26881  V9 ← 001 29C-29D 0668-0669 █▀ █▀ ▄ D891 55441  Draw 08×01 at V8,V9; VF ← XOR 29E-29F 0670-0671  ▀ ▀▀▀▀ 4F00 20224  Skip next if VF <> 000 2A0-2A1 0672-0673 ▄ ▄▀ ▄█ 12A6 04774  Jump to continue 2A2-2A3 0674-0675 █▀ █▀ ▄ D891 55441  Draw 08×01 at V8,V9; VF ← XOR 2A4-2A5 0676-0677 ▄██▄█▄▄█ 69FF 27135  V9 ← 255 The continue routine initializes the key and delta registers, also checking for failure, to restart: 2A6-2A7 0678-0679 ▀▄▀ ▄█▀ A346 41798 continue I ← from 2A8-2A9 0680-0681 ▀██▀ █▀▄ F665 63077  Load V0→V6; I ← I + 07 2AA-2AB 0682-0683  █ ▀ ▀▀ 4B40 19264  Skip next if VB <> 064 2AC-2AD 0684-0685  ▀ ▀ 1200 04608  Jump to 0512 This segment merely calculates the movement deltas, also enforcing bounds: 2AE-2AF 0686-0687 █▀▀▄▄▄▄ E09E 57502 down Skip next if V0 = key 2B0-2B1 0688-0689 ▄ ▄█▄ ▀ 12B8 04792  Jump to left 2B2-2B3 0690-0691  ▀▄▄█▄██ 4B3F 19263  Skip next if VB <> 063 2B4-2B5 0692-0693 ▄ ▄█▄ ▀ 12B8 04792  Jump to left 2B6-2B7 0694-0695  ▀▀ ▀▀▄ 6601 26113  V6 ← 001 2B8-2B9 0696-0697 █▀▀▄▄▄▄▀ E19E 57758 left Skip next if V1 = key 2BA-2BB 0698-0699 ▄▄ ▀ █ 12C2 04802  Jump to right 2BC-2BD 0700-0701  ▀ ▀ ▀ 4A00 18944  Skip next if VA <> 000 2BE-2BF 0702-0703 ▄▄ ▀ █ 12C2 04802  Jump to right 2C0-2C1 0704-0705 ▄██▄▄█▄█ 65FF 26111  V5 ← 255 2C2-2C3 0706-0707 █▀▀▄▄▄█ E29E 58014 right Skip next if V2 = key 2C4-2C5 0708-0709 ▄▄ ▀▄▄▀ 12CC 04812  Jump to up 2C6-2C7 0710-0711  █▄▄█▄█▄ 4A7F 19071  Skip next if VA <> 127 2C8-2C9 0712-0713 ▄▄ ▀▄▄▀ 12CC 04812  Jump to up 2CA-2CB 0714-0715  ▀▀ ▀ █ 6501 25857  V5 ← 001 2CC-2CD 0716-0717 █▀▀▄▄▄█▀ E39E 58270 up Skip next if V3 = key 2CE-2CF 0718-0719 ▄▄ █ ▄█ 12D6 04822  Jump to resolve 2D0-2D1 0720-0721  ▀ ▀ ▀▀ 4B00 19200  Skip next if VB <> 000 2D2-2D3 0722-0723 ▄▄ █ ▄█ 12D6 04822  Jump to resolve 2D4-2D5 0724-0725 ▄██▄▄██▄ 66FF 26367  V6 ← 255 The resolve routine erases the make break so it can't collide with the player, and then redraws him: 2D6-2D7 0726-0727 ▀ ▀▄▄ ▀ A218 41496 resolve I ← player 2D8-2D9 0728-0729 █▀ █▀ ▄ D891 55441  Draw 08×01 at V8,V9; VF ← XOR 2DA-2DB 0730-0731  ▀ ▀▀▀▀ 4F00 20224  Skip next if VF <> 000 2DC-2DD 0732-0733 █▀ █▀ ▄ D891 55441  Draw 08×01 at V8,V9; VF ← XOR 2DE-2DF 0734-0735 █▀▄█▀ ▀▄ DAB1 55985  Draw 08×01 at VA,VB; VF ← XOR 2E0-2E1 0736-0737 ▀▄ ▄▀▄▀ 8A54 35412  VA ← VA + V5; VF ← overflow 2E2-2E3 0738-0739 ▀▄▄ ▀▄▀▀ 8B64 35684  VB ← VB + V6; VF ← overflow 2E4-2E5 0740-0741 █▀▄█▀ ▀▄ DAB1 55985  Draw 08×01 at VA,VB; VF ← XOR The following code determines if the make break is collected by comparing coordinates and resetting: 2E6-2E7 0742-0743 ▄▀▄▀▀ 58A0 22688  Skip next if V8 = VA 2E8-2E9 0744-0745 ▄▄▄█ █ 12F2 04850  Jump to next 2EA-2EB 0746-0747 ▄▀▄█▀ ▀ 59B0 22960  Skip next if V9 = VB 2EC-2ED 0748-0749 ▄▄▄█ █ 12F2 04850  Jump to next 2EE-2EF 0750-0751 ▄██▄█▄▄█ 69FF 27135  V9 ← 255 2F0-2F1 0752-0753  ▀▀▀ ▀▀█ 7701 30465  V7 ← V7 + 001 The next routine moves the player back to his previous location if a collision occurred, then seeing if a make break is used; if so, and the count is positive, the make break's coordinate is calculated and it's drawn. I'd wanted to adjust this based on the last movement direction, but faced pressure: 2F2-2F3 0754-0755  ▀ ▀▀▀▀ 4F00 20224 next Skip next if VF <> 000 2F4-2F5 0756-0757 ▄▄▄█▄▄█ 12FE 04862  Jump to break? 2F6-2F7 0758-0759 █▀▄█▀ ▀▄ DAB1 55985  Draw 08×01 at VA,VB; VF ← XOR 2F8-2F9 0760-0761 ▀▄ ▄▀▄▀▄ 8A55 35413  VA ← VA − V5; VF ← borrow 2FA-2FB 0762-0763 ▀▄▄ ▀▄▀█ 8B65 35685  VB ← VB − V6; VF ← borrow 2FC-2FD 0764-0765 █▀▄█▀ ▀▄ DAB1 55985  Draw 08×01 at VA,VB; VF ← XOR 2FE-2FF 0766-0767 █▀▀▄▄█▄ E49E 58526 break? Skip next if V4 = key 300-301 0768-0769  █ ▄▀▀ 1314 04884  Jump to exhaust delay 302-303 0770-0771  ▀ ▀▀▀ 4700 18176  Skip next if V7 <> 000 304-305 0772-0773  █ ▄▀▀ 1314 04884  Jump to exhaust delay 306-307 0774-0775 ▀ █▄▄ █▀ A33A 41786  I ← make break 308-309 0776-0777 █ ▄ 80A0 32928  V0 ← VA 30A-30B 0778-0779 █ ▄▄ ▀ 81B0 33200  V1 ← VB 30C-30D 0780-0781 ▄███▄▄▄▄ 70FF 28927  V0 ← V0 + 255 30E-30F 0782-0783 ▄███▄▄ ▀ 71FC 29180  V1 ← V1 + 252 310-311 0784-0785 ▄███▄███ 77FF 30719  V7 ← V7 + 255 312-313 0786-0787 ▀▀ █ ▄ D014 53268  Draw 08×04 at V0,V1; VF ← XOR That remaining delay is exhausted, before being reinstated, and one of the maze routines is entered: 314-315 0788-0789 ▀▀▀▀▀███ FF07 65287 exhaust delay VF ← delay 316-317 0790-0791  ▀▀▀▀▀▀ 3F00 16128  Skip next if VF = 000 318-319 0792-0793  █ ▄▀▀ 1314 04884  Jump to exhaust delay 31A-31B 0794-0795 ▀▀▀█ ▄▀▄ F215 61973  delay ← V2 31C-31D 0796-0797  ▀█▀▀ ▀ 3D10 15632  Skip next if VD = 016 31E-31F 0798-0799  █ █ 1212 04626  Jump to maze step 320-321 0800-0801  ▀▄▄█ 120E 04622  Jump to maze This shift routine is better than that preceding it, as it adjusts registers as needed, itself. Had I used a multiplication sled instead, I'd have been able to use this for the maze symbol generation: 322-323 0802-0803 ▀ ▀ 8100 33024 shift V1 ← V0 324-325 0804-0805 ▀▄ ▄▄▄▄ 805E 32862  V0 ← V5 × 2; VF ← MSB 326-327 0806-0807 ▀ █▀▄ ▀▀ B328 45864  Jump to V0 + table 328-329 0808-0809 ▀ ▄ ▄▄▀ 8116 33046 table V1 ← V1 ÷ 2; VF ← LSB 32A-32B 0810-0811 ▀ ▄ ▄▄▀ 8116 33046  V1 ← V1 ÷ 2; VF ← LSB 32C-32D 0812-0813 ▀ ▄ ▄▄▀ 8116 33046  V1 ← V1 ÷ 2; VF ← LSB 32E-32F 0814-0815 ▀ ▄ ▄▄▀ 8116 33046  V1 ← V1 ÷ 2; VF ← LSB 330-331 0816-0817 ▀ ▄ ▄▄▀ 8116 33046  V1 ← V1 ÷ 2; VF ← LSB 332-333 0818-0819 ▀ ▄ ▄▄▀ 8116 33046  V1 ← V1 ÷ 2; VF ← LSB 334-335 0820-0821 ▀ ▄ ▄▄▀ 8116 33046  V1 ← V1 ÷ 2; VF ← LSB 336-337 0822-0823 ▀ ▄ ▄▄▀ 8116 33046  V1 ← V1 ÷ 2; VF ← LSB 338-339 0824-0825 ▄▄▄ ▄▄▄ 00EE 00238  Return The game ends with the various sprites, tables, register banks, and I'll also show the final labels. The backstage begins with a constant symbol, again as that paper I read described this aspect of it: 33A-33B 0826-0827 ████ F0F0 61680 make break 33C-33D 0828-0829 ████ F0F0 61680  33E-33F 0830-0831  ▀▄ ▀▀ 1308 04872 random 340-341 0832-0833 ▄ █▄ 1098 04248  342-343 0834-0835 ███▄ E0F0 57584 drunk 344-345 0836-0837 ▀▀█ E020 57376  346 0838  █ 02 002 from 347 0839  █ 04 004  348 0840  ██ 06 006  349 0841  █ 08 008  34A-34B 0842-0843  0000 00000  34C-34D 0844-0845  0000 00000  34E-34F 0846-0847 ▀▀▀▀ F000 61440 backstage 350-351 0848-0849  0000 00000 stage 352-353 0850-0851  0000 00000  354-355 0852-0853  0000 00000  356-357 0854-0855  0000 00000  358-359 0856-0857  0000 00000  35A-35B 0858-0859  0000 00000  35C-35D 0860-0861  0000 00000  35E-35F 0862-0863  0000 00000  360-361 0864-0865  0000 00000 fourth wall 362-363 0866-0867  0000 00000  364-365 0868-0869  0000 00000  366-367 0870-0871  0000 00000  368-369 0872-0873  0000 00000  36A-36B 0874-0875  0000 00000  36C-36D 0876-0877  0000 00000  36E-36F 0878-0879  0000 00000  370-371 0880-0881  0000 00000 wardrobe This game is much better than that which preceded it, and it was fun to finish it in the final hours of the Octo Jam, as I'd added the make break code haphazardly. I was unable to incorporate an enemy which would opportunistically spawn as the make break does, and also to have better placement of the make break; these are improvements to be made in a later version. The maze is twice the size it was in that prior and the original, and how nice; I'm not finished with this game, sans for the present. .