1/25/2024 0 Comments Gta vice city codes pc en arabe![]() ![]() However, high-level languages have the benefit of generating code based on a fixed set of patterns and are therefore known as "structured languages". C and C++ compilers weren't as efficient as they are now, and programs were smaller. Obviously, it was much more common to find hand-written assembly in older programs. Hand-written assembly is where all bets are off. Compiler optimizations aren't always complicated, so they can be reverse engineered with a bit of work. For example, changing multiplication and division by two into left and right shifts, and multiplication by 9 into the LEA opcode (which can make you think the input is a memory address, although LEA can also be used as a faster way of performing certain multiplications). The real difficulties in writing a reverse compiler comes from two sources: compiler optimizations and hand-written assembly.Ĭompiler optimizations change the source code on the fly, so what's compiled may not be what was written in the source code. Additional work is required when dealing with type-casting and value promotion, but this is actually very easy. For example, the ADD instruction specifies addition of integer operands, while the ADDSS and ADDSD instructions specify addition of single-precision and double-precision operands. CPUs have instructions that specify the types of operands. Yes, they are absolutely able to determine type. One thing I've always wondered about when I hear about decompiling is since I assume that you end up with generated variable names which are largely meaningless strings of text, has anyone ever attempted to write decompilers that attempt to assign useful variable names? I'm not expecting highly decriptive camelcase names, but do decompilers at least attempt to indicate the type? Once you go deep down the rabbit hole, then you have "Linkers & Loaders by John Levine" Some of the above really needs to be required teaching, as you really get a feel for what makes piece of code work.Īnother excellent source is Jon Stokes book "Inside The Machine" This gave you a lot of insight into what went on in the game/programĪ couple of years later there was a windows version & a really nice book that showed you how to optimize windows code using asm.Īt that point all you had was the c sdk with the CreateWindow/CreateWindowEx api calls with the WinMain entry point ![]() There used to be a really cool program called "Sourcerer" that would decompile any dos program into asm ![]() At the time, most stuff were bitmaps with palettes, effects were hard coded or series of sprites applied at run time. there's a lot of technique that were very common at the time and that are now gone. Custom compression algorythm, precompiled assets, bit packing. It mostly comes from the all the quirks and optimisations the developers had to employ to get the most performance out the machines at the time. I've dwelved in a lot of retro DOS/Windows 9x era game digging/dissassembly, mostly for fun, and I must say, the older the games are, the harder they are to reverse engineer. Listing image by RockStar Games Promoted Comments In addition to working on a similar decompilation for Grand Theft Auto: Liberty City Stories, the source code team has also expressed interest in generating PS2 and Xbox ports of the PC version of the game, as well as additional bug fixes. The team built off that code to generate a source version of Vice City that was ready by December 2020, aap wrote. By 2019, the project grew to incorporate other contributors, who were able to generate a working executable by April of 2020. Github contributor "aap" wrote that the project started in early 2018 "initially as a way to test reversed collision and physics code inside the game" by reverse-engineering specific DLLs. The source code can also be used to generate ports of the game to new platforms like Linux, Switch, and PlayStation Vita (though these recompiled versions all require the copyrighted art and music files extracted from the original game). In the case of Grand Theft Auto, those improvements include bug fixes, reduced load times, improved rendering, widescreen monitor support, and a free-floating camera system, to name a few examples. With that code in hand, coders can examine what makes the game tick and make improvements and changes at a much more granular level than with traditional modding. This painstaking, function-by-function process creates raw programming code that can generate exactly the same binary file when compiled. Further Reading Beyond emulation: The massive effort to reverse-engineer N64 source codeWe've discussed in the past how video game fan coders use reverse-engineering techniques to deconstruct the packaged executable files distributed by a game's original developers. ![]()
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