AnachronautandClaude Opus 5
a916103a7f
Everything drawn on this machine was in a cell. Something between two cells meant rewriting both; something moving a pixel at a time meant rewriting them sixty times a second, which is affordable for one thing and not for twenty. A sprite is put at a pixel and the device draws it over whatever is behind, so moving it costs two bytes. MADE OF TILES, which is the decision the rest follows from: m by n taken in reading order from one index, so there is no second pixel format, no second kind of memory, and nothing a sprite can show that the map cannot. A 16 by 16 character is four tiles and the background can name the same four. 256 entries of 8 bytes at 0xC000 in the atlas - eight so the entry address is a shift, the same no-multiply argument as the palette's four. Position is signed and sixteen bits, because 640 by 400 does not fit in a byte and a sprite has to be able to sit half off the left rather than appearing whole at the edge. A PIXEL OF ZERO IS NOT DRAWN, or every sprite is a rectangle. Tested before the attribute is added, so a hole belongs to the art and not to the colour scheme. The same rule the other way round is what "behind" means: drawn only where the background pixel was zero, so a thing walks behind a pillar and in front of the floor in one frame. All of them draw, every frame, so they cannot flicker. Real machines dropped them per scanline because they had a fixed number of shift registers; this has a loop. The limit is the size of the table, which is a constant rather than a property of what is on screen. And the system takes them down at exit. The sprite table sits in the gap the screen save walks around - to the end of the map, then the palette - and that is right, because nothing the shell draws is a sprite: there is nothing to give back, only something to take away. Otherwise a program that put a ball up and left would leave it over the prompt, in front of everything, with nothing able to type it away. Sprite.asm deliberately leaves its own, because a program that faulted could not have cleared it. Every check here was re-broken and failed: transparency, reading order, draw order, priority, and size. Size needed breaking twice - the first attempt did not compile, and a silent build failure had left the old binary passing. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW
130 lines
3.2 KiB
Plaintext
130 lines
3.2 KiB
Plaintext
CosmOS
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> monitor
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x examine, d disassemble, a assemble, s set, b bank, g go, exit leaves
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* b nonsense
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b <program|data|number>
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* b 9
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there is no such bank
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* load greet.sbx
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loaded, starting at 5000
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* b program
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bank 00
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* d 5000
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5000 47 00 30 00 SETD.0 3000
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5004 72 10 SWI 10
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5006 47 00 30 44 SETD.0 3044
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500A 72 10 SWI 10
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500C 47 00 30 7A SETD.0 307A
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5010 27 1F INIB 1F
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5012 72 11 SWI 11
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5014 47 00 30 5D SETD.0 305D
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* x 5000
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5000 47 00 30 00 72 10 47 00 30 44 72 10 47 00 30 7A G.0.r.G.0Dr.G.0z
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5010 27 1F 72 11 47 00 30 5D 72 10 47 00 30 7A 72 10 '.r.G.0]r.G.0zr.
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5020 47 00 30 65 72 10 20 72 12 00 00 00 00 00 00 00 G.0er. r........
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5030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
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* b data
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bank 01
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* x 3000
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3000 61 20 70 72 6F 67 72 61 6D 2C 20 6C 6F 61 64 65 a program, loade
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3010 64 20 6F 66 66 20 61 20 64 69 73 6B 2C 20 72 75 d off a disk, ru
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3020 6E 6E 69 6E 67 20 6F 6E 20 74 68 65 20 73 79 73 nning on the sys
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3030 74 65 6D 20 74 68 61 74 20 6C 6F 61 64 65 64 20 tem that loaded
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* b 2
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bank 02
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* x 0
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0000 01 FF 00 00 00 00 00 00 01 FF 00 00 00 00 00 00 ................
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0010 03 FF 08 00 00 00 00 00 01 20 01 00 00 00 00 00 ......... ......
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0020 00 FF 00 00 00 00 00 00 00 FF 00 00 00 00 00 00 ................
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0030 00 FF 00 00 00 00 00 00 00 FF 00 00 00 00 00 00 ................
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* s 0 FF
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that bank will not be written
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* b program
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bank 00
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* s 8000 26 48 D1 00 26 0A D1 00 18 12
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* d 8000
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8000 26 48 INIA 48
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8002 D1 00 OUTA 00
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8004 26 0A INIA 0A
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8006 D1 00 OUTA 00
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8008 18 SHR
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8009 12 AND
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800A 00 ?
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800B 00 ?
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* g 8000
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H
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that byte is not an instruction, at 800A
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A 85 B 3F Q 05
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the program was stopped
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* d 8000
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8000 26 48 INIA 48
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8002 D1 00 OUTA 00
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8004 26 0A INIA 0A
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8006 D1 00 OUTA 00
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8008 18 SHR
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8009 12 AND
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800A 00 ?
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800B 00 ?
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* b data
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bank 01
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* s 8100 68 65 6C 6C 6F 2C 20 74 79 70 65 64 0A 00
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* b program
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bank 00
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* a 8200
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8200: SETD.0 8100
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8204: SWI 10
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8206: lda.2
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8208: LDD.0.1
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820B: frobnicate
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no such instruction
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820B: INIA
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that one needs a value after it
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820B: SWI 12
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820D: .
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* d 8200
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8200 47 00 81 00 SETD.0 8100
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8204 72 10 SWI 10
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8206 42 02 LDA.2
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8208 4A 00 01 LDD.0.1
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820B 72 12 SWI 12
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820D 00 ?
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820E 00 ?
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820F 00 ?
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* g 8200
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hello, typed
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finished
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* exit
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> dir
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greet.sbx 211
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hello.sbx 53
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Life.sbx 1396
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Snake.sbx 2164
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Keys.sbx 664
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Say.sbx 156
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Break.sbx 149
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Grid.sbx 571
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Press.sbx 872
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Mode.sbx 48
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Flip.sbx 173
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Sprite.sbx 442
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Crash.sbx 632
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vars.script 50
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blocks.script 343
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loops.script 272
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tune.sbx 306
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notes.txt 21
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Apps <dir>
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hi.script 121
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bad.script 45
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plain.script 24
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cross.script 280
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nonl.script 38
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outer.script 376
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inner.script 44
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loop.script 35
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26 files, 1 directory
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> exit
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halted
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Execution halted.
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[exit 0]
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