Weird things I learned while writing an x86 emulator

Re:Weird things I learned while writing an x86 emulator by timmisiak on Friday February 03, 2023 @01:27PM (#34645643)

Funny enough, we tried going down the road of doing a JIT, but for our use cases pure emulation was often fast enough and it wasn't worth the extra complexity to do JIT. Part of that is probably due to the architecture of how TTD works, but part of it is how efficient we were able to get with the emulation mode. Later, a different emulator was created for running x86 code on ARM64, and that one uses an extremely efficient JIT. (I didn't get to work on the x86-on-arm64 emulator though. Would have been fun)

Working on the JIT in TTD was a lot of fun though, and it's a shame it didn't make sense to keep it around.

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Re:Weird things I learned while writing an x86 emulator by mark_undoio on Saturday February 04, 2023 @07:50AM (#34654063)

Very impressive you got such good performance out of straight emulation! And WinDbg TTD runs with truly parallel threaded execution within one process, which we do not (yet).

I'm surprised a JIT wasn't worth it but, from what I'm aware of, I can see a few reasons why the trade offs are different.

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