- [x] I have read and followed the [Contribution Guidelines](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/CONTRIBUTING.md#code-contributions).
- [x] I have read and followed the [AI Policy](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/docs/policies/AI.md)
- [x] I have read and followed the [Coding Guidelines](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/docs/policies/Coding.md) to the best of my ability.
-------------------
Problem: In cyrilic idioms, Absolum won't past beyond 1st area (intro miniboss).
From the user panic i`ve extracted these strings:
> GlobalState.request_next()
> save_state_to_saveGame(...)
> platform.ProcessSave()
> bin_serialize_to_file(...)
> StandaloneTypeModel.Write(SaveGame, ...)
> Write(SaveGame.AdventureSaveSlot, ...)
> Write(PlayerState, ...)
> ProtoBuf.ProtoWriter.WriteString(...) + 0xcc
> ProtoBuf.Helpers.DebugAssert(...)
> Debug.Fail(...)
By debugging ProtoBuf.ProtoWriter.WriteString(...) argument it was found that the string Отлично! (Great! expression for combos between 6 and 30 iirc) was reaching a size comparison of different values and causing an assert in guest side..
It seems the game tries to save highest combo level. I've managed to skip this bug by doing a perfect combo for entire level, so that the problematic word never was generated or attempted to be saved.
After further research, the issue chain was identified: Game maths literal string size via two ways and compare, and one of them was getting replaced by a wrong value due to Eden letting the literal string be interpreted as a real instruction.
Logic added:
const bool pair = decltype(l)::ExtractValue(raw) & 1;
const bool fixed_rt2 = decltype(rt2)::ExtractValue(raw) == 0b11111;
return pair || fixed_rt2;
- pair checks bit 21 (L & 1): register-pair instructions actually use Rt2, so they remain accepted.
- For single-register forms, require Rt2 == 31. The table word fails this check, so NCE leaves it intact.
Sources
https://www.scs.stanford.edu/~zyedidia/arm64/stxrb.htmlhttps://www.scs.stanford.edu/~zyedidia/arm64/stxp.htmlhttps://github.com/qemu/qemu/blob/master/target/arm/tcg/a64.decode#L344
Altough the solution is a case specific guard, it is data agnostic: This is a true fix to avoid a specific case in which a literal may be interpreted as a valid instruction, without interfering with other true instruction cases.
Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4369
Reviewed-by: lizzie <lizzie@eden-emu.dev>
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>
xbzk
lizzie
Liam