📝 Posted:

2020-03-22 09:18 UTC

🚚 Summary of:

P0084

⌨ Commits:

dfac2f2...110d6dd

💰 Funded by:

Yanga

🏷 Tags:

th01

-

rec98

+

file-format

+

score

+

tasm

-

Final TH01 RE push for the time being, and as expected, we've got the superficially final piece of shared code between the TH01 executables. However, just having a single implementation for loading and recreating the REYHI*.DAT score files would have been way above ZUN's standards of consistency. So ZUN had the unique idea to mix up the file I/O APIs, using master.lib functions in REIIDEN.EXE, and POSIX functions (along with error messages and disabled interrupts) in FUUIN.EXE… Could have been worse though, as it was possible to abstract that away quite nicely.

That code wasn't quite in the natural way of decompilation either. As it turns out though, 📝 segment splitting isn't so painful after all if one of the new segments only has a few functions. Definitely going to do that more often from now on, since it allows a much larger number of functions to be immediately decompiled. Which is always superior to somehow transforming a function's ASM into a form that I can confidently call "reverse-engineered", only to revisit it again later for its decompilation.

And while I unfortunately missed 25% of total RE by a bit, this push reached two other and perhaps even more significant milestones:

• 📝 In a little over 6 months, we've doubled the amount of reverse-engineered PC-98 Touhou game code! 📈
• After (finally) compressing all unknown parts of the BSS segments using arrays, the number of remaining lines in the REIIDEN.EXE ASM dump has fallen below TASM's limit of 65,535. Which means that we no longer need that annoying th01_reiiden_2.inc file that everyone has forgotten about at least once.

Next up, PI milestones!