Case study

u5d: a semantic-match Ultima V decompilation

u5d reconstructs C source for Ultima V: Warriors of Destiny and compares it with the MS-DOS v1.16 program at the assembly-semantic level. The author reports that the modern version can be played through to the ending using original game data. The author reports approximately 95% matching for ULTIMA.EXE, excluding assembly functions, and approximately 95% for the overlays.

Targets: Game
Category: Independent reconstruction cases
Relationship: Independent reconstruction project
Sources reviewed: 2026-11-06
Evidence class: C2 code & docs, no demo or download

Stars: 9
Last commit: 2026-10-28
Language: C

GitHub data as of 2026-11-10

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Evidence

Observed: Code, documentation and a download method observed; no demo found.
Checked: 2026-11-09

How evidence classes are assigned

Requirements & limits

Prerequisites: Original Ultima V data files are required to play.
Prerequisites: Windows builds use Visual Studio 2026. The DOS target uses DJGPP; the Microsoft C 5.1 target is used for disassembly matching and cannot currently link an executable.
Limits: The original linker is unavailable, so a byte-identical binary match is not currently possible; bugs may remain.
License: No licence file in the repository.

Cite

BibTeX

@misc{u5d-ultima-v-case,
  title = {{u5d: a semantic-match Ultima V decompilation}},
  howpublished = {\url{https://github.com/wonst719/u5d}},
  url = {https://github.com/wonst719/u5d},
  urldate = {2026-11-06},
  note = {Awesome REA entry: \url{https://awesomerea.org/resources/u5d-ultima-v-case/}}
}

Plain text

u5d: a semantic-match Ultima V decompilation. https://github.com/wonst719/u5d (accessed 2026-11-06). Awesome REA entry: https://awesomerea.org/resources/u5d-ultima-v-case/

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Primary sources

README.md GitHub · wonst719/u5d · Revision 6c7085e