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1. Embed this notice
   Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:31 JST Foone🏳️‍⚧️

   I don't know if I'm weird or if it's just normal to get random reverse engineering urges.
   like right now I have like 5 major RE tasks I'm halfway done with, I'm hacking a bunch of games (and more interesting things), but my brain is just like "you need to reverse engineer a game that uses a software 3D renderer"

   • Embed this notice
     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:48:52 JST Foone🏳️‍⚧️

     in reply to

     the best place to stick dynamically loaded code: INSIDE AN INTERRUPT HANDLER

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:48:53 JST Foone🏳️‍⚧️

     in reply to

     I think they're dynamically loading code and stuffing it into the tick handler

     Rich Felker and Ryan Castellucci :nonbinary_flag: repeated this.
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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:48:54 JST Foone🏳️‍⚧️

     in reply to

     at least they remembered to call CLI first

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:48:55 JST Foone🏳️‍⚧️

     in reply to

     weird.
     it stores the video mode selected (1-3) in 1000:912d, then stores the video mode TIMES TWO in 1000:912e and 1000:6646

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:48:55 JST Foone🏳️‍⚧️

     in reply to

     why bother using the DOS api for changing interrupt handlers, when you can just address segment zero? WHY NOT INDEED, ECHELON?

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:48:56 JST Foone🏳️‍⚧️

     in reply to

     okay so video mode hercules is actually CGA but with a flag set.

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:48:57 JST Foone🏳️‍⚧️

     in reply to

     so lets instead search the whole program for the scalar 6648 and OH LOOK IT'S REFERENCED AFTER ALL

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:48:57 JST Foone🏳️‍⚧️

     in reply to

     ghidra: I know decompilers that understand segments and they're all cowards

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:48:58 JST Foone🏳️‍⚧️

     in reply to

     the what video mode do you want? string starts at 1000:6648 and it's referenced from... nowhere. or so ghidra thinks.

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:48:59 JST Foone🏳️‍⚧️

     in reply to

     so when the game launches it asks me what video mode I want (Hercules, CGA, Tandy/Amstrad, or VGA) and then asks me to insert the data disk. This is not fun, since I always give it the same answers. So let's fix that

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:00 JST Foone🏳️‍⚧️

     in reply to

     the game hangs if you try to copy the wrong .ARE file into the place, so I suspect there's some internal location references or something that break

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:01 JST Foone🏳️‍⚧️

     in reply to

     there's some values over 0x80 in the decompressed out so I think I'm misunderstanding the decompression

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:01 JST Foone🏳️‍⚧️

     in reply to

     I wonder of those 6-byte chunks are objects? like, x-pos, y-pos, z-pos, look up object ID in the CMP file?

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:02 JST Foone🏳️‍⚧️

     in reply to

     NOPE I'm completely wrong. They've got ES and DS pointing at different segments.
     2CEF is the start (I guess?) of the output buffer, in a different segment

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:03 JST Foone🏳️‍⚧️

     in reply to

     okay I'm following through the decompress loading A3.ARE. I can see in the data segment we've got the data in the file, but up at 2CEF? all zeros. now if I wait for this function to return, that should get filled out

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:04 JST Foone🏳️‍⚧️

     in reply to

     the files have a 2 byte header that's ignored and not checked, then a number of things.
     those things are 6-byte chunks that get copied into the buffer above 0x1427. No idea why yet.

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:04 JST Foone🏳️‍⚧️

     in reply to

     It seems the way the function works that it's passed a buffer as DS, then it loads the file starting from address 0, and writes that into 0x2CEF and up That's 11k into the buffer, so well above any real file.

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:05 JST Foone🏳️‍⚧️

     in reply to

     so 44 82 44 turns into 44 00 00 44

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:06 JST Foone🏳️‍⚧️

     in reply to

     the calling code changes the data segment to one just used for your specific buffer, so you don't need a pointer, it's just in the implicit state of the processor. you just work from 2

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:06 JST Foone🏳️‍⚧️

     in reply to

     okay I haven't checked against the actual output (since I haven't gotten the actual output yet) but I think this isn't huffman, it's not even regular RLE, it's Very Simple RLE: You can represent all bytes 00-7F normally, but if the high bit is set, it instead means "repeat this many zeros"

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:07 JST Foone🏳️‍⚧️

     in reply to

     16bit assembly is so silly.
     You enter a function and step one is you make a pointer to 2, and then increment from there

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:08 JST Foone🏳️‍⚧️

     in reply to

     uh-oh.

     after loading the file, it calls two functions. One seems to just be shoving it into memory, but the other shows up as blank, and instant ret.

     That smells like dynamic code loading and I don't like that

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:09 JST Foone🏳️‍⚧️

     in reply to

     Ghidra: I support disassembly of 16-bit DOS programs!
     also Ghidra: WHAT THE FUCK IS "DS"? all segment-relative poitners are aimed at segment 0000, right?

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:09 JST Foone🏳️‍⚧️

     in reply to

     either ghidra's set-register doesn't work or I don't understand what it's doing

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:10 JST Foone🏳️‍⚧️

     in reply to

     ahh. so it's got a string in the EXE that's A0.ARE.
     Then it has another string that's 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ.
     So when it wants to load area N, it indexes into the Nth item of the second string, then shoves it in over the 0 in A0.ARE and opens that file

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:11 JST Foone🏳️‍⚧️

     in reply to

     but I bet it's because it can read non-huffman'd files, and 8192 + 2 byte header?

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:12 JST Foone🏳️‍⚧️

     in reply to

     ahh, I think I was looking at a custom loader that just handles TITLE.HUF

     (which is 7687 but presumably the files is re-opened later?)

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:12 JST Foone🏳️‍⚧️

     in reply to

     yeah the version that works for maps loads 8194 bytes.

     which is an annoying number.

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:13 JST Foone🏳️‍⚧️

     in reply to

     I think this game was programmed in assembly. passing one pointer in SI is not a calling convention I have seen compilers use

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:14 JST Foone🏳️‍⚧️

     in reply to

     interesting. this code that opens A2.ARE reads 1536 bytes and then closes it.

     the file is 2432 bytes, though

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:15 JST Foone🏳️‍⚧️

     in reply to

     I suspect the maps are compressed too.

     time to find the decompress routine in the exe!

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:16 JST Foone🏳️‍⚧️

     in reply to

     here's P0.HUF to show what I mean about corruption:

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:16 JST Foone🏳️‍⚧️

     in reply to

     CMP files seem to contain object info, since I see text in them.

     the game supposedly has 240 objects on the map, which can be transported onto your ship when found. Some are useless, some are clues to The Main Puzzle, and some are instant death bombs

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:17 JST Foone🏳️‍⚧️

     in reply to

     for the ones with 0/1 versions (COVE and DASH), 0 seems be the CGA/Monochrome version, while 1 is the VGA version

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:18 JST Foone🏳️‍⚧️

     in reply to

     it seems to only render the first half and then the rest is gibberish. I bet it's something to do with these files being multi-format, since they have to encode the image for VGA/CGA/Monochrome

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:18 JST Foone🏳️‍⚧️

     in reply to

     okay so P0-5 are the artifact pictures, DASH is the dashboard, COVE is some castle (end of game?) and title is... the title

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:19 JST Foone🏳️‍⚧️

     in reply to

     anyway, the game starts up by showing you TITLE.HUF.

     let's just swap out all the other HUF files one by one and see what they are!

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:20 JST Foone🏳️‍⚧️

     in reply to

     there's a reference to a covex.huf file in the EXE, but it's not included in this version.
     Maybe COVE0/COVE1 are short for COVEX?

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:20 JST Foone🏳️‍⚧️

     in reply to

     I think the HUF files are compressed, at least somewhat. Just not very well.

     Either that or they're some kind of image drawing microcode but I kinda doubt it

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:21 JST Foone🏳️‍⚧️

     in reply to

     arg I don't have a memory scanner that'll work on the game right now. I can't easily make cheats for infinite health and fuel and shit

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:21 JST Foone🏳️‍⚧️

     in reply to

     EXE isn't packed, it's about 90 kilobytes.

     Other files: 16 CMP files, and a bunch of HUF files.
     6 labeled P0 - P5, TITLE, DASH0/1, COVE0/1? Sounds like they're image files .

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:22 JST Foone🏳️‍⚧️

     in reply to

     Each .ARE file is only 3 kilobytes so all 36 of them only use up 96 kilobytes, but this game was born on the c64, where that was more RAM than the whole system had

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:23 JST Foone🏳️‍⚧️

     in reply to

     Which makes sense if we look at the map included in the box:
     It's a 6x6 grid, labeled A-F, 1-6.

     So clearly the game is storing map chunks in these .ARE files and loading them as needed.

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:24 JST Foone🏳️‍⚧️

     in reply to

     the game has 36 .ARE files, named A0 through AZ.

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:25 JST Foone🏳️‍⚧️

     in reply to

     okay so I set a interrupt breakpoint (bpint in the DOSBOX debugger) on AH=3D, and AH=0F. Those are the two main ways to open files on DOS, the early way (0F) and the later way (3D). Flew around until the game pauses, and it's trying to load A2.ARE

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:26 JST Foone🏳️‍⚧️

     in reply to

     I think that system had some PIC problem, because it crashed more than once while games were doing weird CPU-based animation/audio tricks

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:26 JST Foone🏳️‍⚧️

     in reply to

     and I have crashed the game. maybe this isn't emulated terribly well

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:27 JST Foone🏳️‍⚧️

     in reply to

     Echelon was technically the first video game I ever owned. Shortly after my family got our first PC (a Heavily Used Packard Bell 486), my dad picked up a copy at a thrift store or something.
     I never beat the game, especially because it only had a 50/50% chance of launching on my PC

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:28 JST Foone🏳️‍⚧️

     in reply to

     maybe I should just go back so far I find a DOS game that doesn't need segments and overlays because it's only 64kb

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:28 JST Foone🏳️‍⚧️

     in reply to

     1987 Wireframe flightsim/puzzle Echelon?

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:29 JST Foone🏳️‍⚧️

     in reply to

     on the other hand, 3/4 of those are DOS games. I have done so many DOS games and I think I'm overdosed on having to deal with segments and overlays.

     maybe win9x games are a better idea for relaxation

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:30 JST Foone🏳️‍⚧️

     in reply to

     3D game ideas I might could hack on for just why not reasons:
     1. MindTrap (it glitches on later windows, would be nice to fix it, even if no one but me cares)
     2. Betrayal at Krondor: The overworlds are cool!
     3. Abrams Battle Tank by Dynamix/EA ?
     4. 688 Attack Sub

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Saturday, 28-Dec-2024 13:49:31 JST Foone🏳️‍⚧️

     in reply to

     me, yearning: man, I wish I could reverse engineer something with a software 3D renderer...

     3D Movie Maker: what? are you serious?
     Corncob 3d: AM I A JOKE TO YOU?
     hell, Office 95: YOU STILL NEED TO GET BACK TO ME

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:40:46 JST Foone🏳️‍⚧️

     in reply to

     when a sector isn't loaded it's rendered like it's there anyway, but empty.

     So when you're at A05 and looking west, you should be seeing what's in B14. And you are... because B14 is empty. The stuff doesn't start to B13, which you can only see by traveling into B14 and loading that area instead

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:40:47 JST Foone🏳️‍⚧️

     in reply to

     but it can only have on area loaded.
     So when you're at A01, you should have parts of three other areas visible... it solves this in a silly but simple fashion:

     There's nothing at the borders.

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:40:48 JST Foone🏳️‍⚧️

     in reply to

     I wonder if it'll break if I put all 242 items into one area

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:40:48 JST Foone🏳️‍⚧️

     in reply to

     so the game works by only having a 3x3 sector grid rendered, but those sectors are inside of Areas, and it can only have one area loaded at once. So if you're at sector B02, you have A01, A02, A03, B01,B02,B03, C01,C02,& C03 loaded.

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:40:49 JST Foone🏳️‍⚧️

     in reply to

     okay I can figure out where all the items are now

     C:\DOSBox-X\drive_c\Echelon\py>python decode.py ..\Az.ARE az.out
     header=(0, 144),n_items=5
     icon=0,itemid=2,sector=D04,x=6528,y=4992,c6=31
     icon=96,itemid=128,sector=D11,x=7552,y=7040,c6=3
     icon=108,itemid=152,sector=D11,x=3712,y=4992,c6=33
     icon=20,itemid=41,sector=E06,x=5760,y=6784,c6=18
     icon=18,itemid=38,sector=L11,x=3456,y=7296,c6=1

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:40:50 JST Foone🏳️‍⚧️

     in reply to

     byte 4 is Y-position using the same rules (origin is at bottom left)

     No idea what byte 5 means. it's set to 18, but changing it to 0 or FF or anything in between seems to change nothing

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:40:51 JST Foone🏳️‍⚧️

     in reply to

     okay so the 6-byte format is:
     byte 0: icon
     byte 1: what it is
     byte 2: what sector it is in

     bytes 3-5 are for intra-sector positioning (presumably). now to try and figure that shit out

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:40:51 JST Foone🏳️‍⚧️

     in reply to

     okay this is weird. Byte 3 is the x-position within the sector, and it can have (valid) positions between -19 and +19.

     If you go above or below that range, it'll get placed into neighboring sectors, which fucks up the game's item detection. It only looks in the current sector for items, but it won't see an item that's one sector over but positioned at -50

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:40:52 JST Foone🏳️‍⚧️

     in reply to

     hey look there it is.

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:40:53 JST Foone🏳️‍⚧️

     in reply to

     so if I change it to 71 (hex 0x47) it should move to sector D07

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:40:54 JST Foone🏳️‍⚧️

     in reply to

     which I think means it has a positional resolution of like 35 meters, given that each sector is 10km across

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:40:54 JST Foone🏳️‍⚧️

     in reply to

     fuck me these are nibble addresses

     I entered "87", which is hex 0x57, and it's in sector E07
     E is the 5th letter of the alphabet. so it's sector E07.

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:40:55 JST Foone🏳️‍⚧️

     in reply to

     ahh. I think it's (effectively) using big endian numbers. See, the coordinates aren't linear X/Y, they're "which sector" and then (maybe) "where within the sector".

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:40:56 JST Foone🏳️‍⚧️

     in reply to

     the first byte seems to be which icon to use. I can adjust it, and the thing still picks up as the mining probe, but it looks different in the preview

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:40:56 JST Foone🏳️‍⚧️

     in reply to

     next byte seems to be what it is.
     I set it to 08 and got a Data Storage Laser Disk [sic]

     I think this guy was murdered, I found out from looking at the files that there's a dead body you can find somewhere, and I think it's mr. Allen

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:40:57 JST Foone🏳️‍⚧️

     in reply to

     yeah this makes no sense.

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:40:58 JST Foone🏳️‍⚧️

     in reply to

     I'm gonna need a spreadsheet for this

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:40:59 JST Foone🏳️‍⚧️

     in reply to

     yeah I narrowed down the item I'm floating over to one specific chunk.
     I set the last short in the chunk to 4312 and the item changed Z coord to (approx) 4761.

     The value was original 4615 and it was at Z coord 6794. ugh.

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:40:59 JST Foone🏳️‍⚧️

     in reply to

     WHY ARE THE SCALES DIFFERENT

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:41:00 JST Foone🏳️‍⚧️

     in reply to

     which does mean I can figure out how many items are in each area, easily. Read the 3rd byte of every area file!

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:41:00 JST Foone🏳️‍⚧️

     in reply to

     I have done so. The Area you start in is the only one with zero items.

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:41:01 JST Foone🏳️‍⚧️

     in reply to

     okay I think that 6-byte-chunks thing at the top of the file is items. I went and sat on top of an item, then edited the file so instead of 5-chunks it had 0, then reloaded the area (by hyperspacing out and then back in ) and suddenly the item is gone

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:41:02 JST Foone🏳️‍⚧️

     in reply to

     So the game has an alien language that's written on lots of artifacts, right?

     You can see some of it here, on this mining probe I picked up

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:41:02 JST Foone🏳️‍⚧️

     in reply to

     But like most alien languages in games, it's just a alternate alphabet on english.

     So I found the alphabet in the EXE and overwrote it with one of the other two fonts, and now it's plain english:

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:41:03 JST Foone🏳️‍⚧️

     in reply to

     I'm gonna have to expand my patching system to let me patch PNGs into EXEs as binary data

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:41:04 JST Foone🏳️‍⚧️

     in reply to

     also based on the scale this game says it functions at, your one-man fighter jet/spaceship is approximately 500 meters (1640') long

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:41:05 JST Foone🏳️‍⚧️

     in reply to

     it keeps crashing when I modify it. I think I found the font routine, though, which'll help hack more

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:41:05 JST Foone🏳️‍⚧️

     in reply to

     I think the map format might be tile-based rather than wireframes. You see (on the map) how the rocks in the sector to the bottom-left are the same as the ones in the top-right? That'd make sense if it's just a single value selecting what set of 3D geometry to stuff in the square

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:41:06 JST Foone🏳️‍⚧️

     in reply to

     I tried to glitch up the map to see what it meant, but I accidentally glitched it too hard and got stuck in an infinite divide by zero glitch

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:41:07 JST Foone🏳️‍⚧️

     in reply to

     this compresses the file from 2.36 kilobytes down to an amazing 2.25 kilobytes

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:41:08 JST Foone🏳️‍⚧️

     in reply to

     interesting. so the .ARE files have a 140 near the top, and the manual says each AREA is 140 kilometers.

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:41:08 JST Foone🏳️‍⚧️

     in reply to

     the RLE compression seems to only affect the first 256 bytes of the file (after the 6-byte chunks). fucking weird. But I wrote some code that does the same, and it matches.

   • Embed this notice
     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:41:09 JST Foone🏳️‍⚧️

     in reply to

     for some reason ghidra thinks some of the calls are going into the data segment instead of CS

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:41:10 JST Foone🏳️‍⚧️

     in reply to

     the way ghidra handles interrupts is profoundly broken and someone needs to fix it. someone might have already, I just haven't installed that incomplete dos loader

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:41:10 JST Foone🏳️‍⚧️

     in reply to

     oh ghidra is just completely wrong about where this call goes. that's... fine

   • Embed this notice
     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:41:11 JST Foone🏳️‍⚧️

     in reply to

     I guess it's puts(), not printf

     But yeah. It doesn't feel like an inlined function, it's just a macro

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     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:41:12 JST Foone🏳️‍⚧️

     in reply to

     patch 0xDF0A with 90 90 90 to skip disk check
     patch 0xE2BF with C6 C0 33 90 90 90 to skip video check. 33=VGA, 32=Tandy/Amstrad, 31=CGA, 68=Hercules

   • Embed this notice
     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:41:12 JST Foone🏳️‍⚧️

     in reply to

     I think this was written with a macro assembler by someone who loved macros.
     Like there's a lot of times where the code would be like
     LEA EAX, SomeString
     CALL PRINTF

     in a saner world, but instead there's a loop that uses global memory addresses and calls the BIOS TELETYPE OUTPUT call letter by letter. and that loop appears in every function that needs to do printf()

   • Embed this notice
     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:41:13 JST Foone🏳️‍⚧️

     in reply to

     anyway for now I can just skip the disk swap check by patching out CALL DiskSwapCheck, since it has no side-effects.
     The video mode check unfortunately does, so I gotta leave it in but hack it to think I said "VGA"

   • Embed this notice
     Foone🏳️‍⚧️ (foone@digipres.club)'s status on Sunday, 29-Dec-2024 17:41:14 JST Foone🏳️‍⚧️

     in reply to

     I need to turn my patching shit form Super Solvers Gizmos & Gadgets into a generic thing I can use on any game. That'd be sweet

   • Embed this notice
     sneak (sneak@s.sneak.berlin)'s status on Sunday, 29-Dec-2024 21:32:43 JST sneak

     in reply to

     @foone "i don't know if i'm weird"