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by zbentley10 hours ago |
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upvoteby yjftsjthsd-h6 hours ago|
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WINE emulates an ABI, rather than a CPU or such, but I'd happily argue that that's an emulator. (In fairness, though it's not generally described that way, I would call web polyfills API emulation)
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upvoteby actionfromafar1 hours ago|
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It implements an ABI.

It "emulates a behaviour" and natural language is fluid, so sure, you could call WINE an emulator and I wouldn't be mad at you. But WINE is very different compared to what most emulators are. Usually the term is reserved for when you emulate in software what used to be hardware.

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upvoteby leidenfrost10 hours ago|
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Wine as a polyfill makes so much more sense
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upvoteby userbinator9 hours ago|
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I believe WINE doesn't actually translate any instructions; it's a Windows PE loader and a bunch of libraries that implement Windows APIs using Linux equivalents.
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upvoteby throwaway274489 hours ago|
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How does it handle stuff like syscalls without altering the executed code?
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upvoteby pcwalton8 hours ago|
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Windows apps don't use syscalls directly; they call into kernel32.dll, which is convenient for Wine. (Microsoft enforces this by scrambling the syscall numbers on OS updates [1].)

[1]: https://j00ru.vexillium.org/syscalls/nt/64/

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upvoteby throwaway274486 hours ago|
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Huh, now I know. I suppose macos is the same way these days even if you can technically bypass it.
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upvoteby Conan_Kudo5 hours ago|
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Yes. Linux is the only major operating system where there is even a convention to directly access system calls. For macOS, everything goes through libSystem.
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upvoteby aunderscored8 hours ago|
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It installs handlers. I don't have the exact name but there's support in the kernel to redirect syscalls to a Userland process
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upvoteby actionfromafar34 minutes ago|
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https://www.phoronix.com/news/Wine-11.5-Released

"SUD" Syscall User Dispatch feature in Linux 5.11 +

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upvoteby throwaway274489 hours ago|
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> It lightly translates binary formats (Windows executables) into Linux-compatible executable code,

Does this not involve transpilation? I guess I was grouping that in under dynamic recompilation and AOT techniques.

Regardless, I don't think that there's a benefit from defining emulation from an implementation rather than an empirical perspective. If it runs a chunk of code as if it were in a different environment, I'm kind of ok to call it an emulator. To the sibling's point, a polyfill would also fit as an emulation layer here.

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upvoteby ecnahc5158 hours ago|
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Not necessarily. It could just rewrite the outer portion to be an ELF loader that then calls into a runtime that actually shims the syscalls for example. I don't think WINE does exactly this but it's not really transpiling either.
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upvoteby yjftsjthsd-h5 hours ago|
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You don't even need that, really; just have wine load the PE binary into memory and hand it a bunch of DLLs that use Linux syscalls under the hood. It's less transpiler and more of a funky dynamic linker+loader plus libraries.
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