I don't know if I'm weird or if it's just normal to get random reverse engineering urges.
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@gewt I can't remember that one either
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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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1987 Wireframe flightsim/puzzle Echelon?
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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 -
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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and I have crashed the game. maybe this isn't emulated terribly well
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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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the game has 36 .ARE files, named A0 through AZ.
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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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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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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 I'm only interested in .ARR files.
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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 . -
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? -
@grumpygamer well I did pirate this version of the game, since I'm too lazy to go find that 5.25" disk in my storage unit, so technically all these files are .ARR files!
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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 HUF for Huffman, surely?
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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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@growf that'd make sense!
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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
