And of course, TH05 ruins the consistency once again. Sure, the added
file error handling is nice, but we also have changes in the playful
messages (lol), and now need a third distinct optimization barrier
(🤦)… But as it turns out, inlined calls to empty functions work as
well. They also seem closer to what ZUN might have actually written
there, given that their function body could have been removed by the
preprocessor, similar to the logging functions in the Windows Touhou
games. (With the difference that the latter infamously *aren't*
inlined…)
Part of P0077, funded by Splashman and -Tom-.
Oh wow, caff4fe introduced wrong bytes into RES_KSO.COM by confusing
[cfg_bombs] with [credit_lives] -.- Which I didn't find out back then
because all the RES_*.COM binaries still had some different instruction
encodings anyway and I just didn't care enough to base my diff of those
files on the wrong encoding versions to notice the bug…
Whoops.
Part of P0077, funded by Splashman and -Tom-.
4½ years after aa56a7c, it turns out that the correct decompilation
involves… no-ops generated by assigning variables that just happen to
be in registers to themselves?! Which does get optimized out, but only
after TCC folded identical tail code in all branches of a function,
thus effectively functioning as an optimization barrier.
The initial attempt used register pseudovariables, but this definitely
is the best possible way this could work – portable, and doesn't
unnecessarily shred the code into tiny inlined functions pieces. The
mindblowing thing here is that ZUN could have actually written this to
have additional, albeit unnecessary, lines to place breakpoints on. But
that means he must have chosen those two local variables in SI and DI
completely by chance… 🤯
The best thing though? ~#pragma inline is gone~
Part of P0076, funded by [Anonymous] and -Tom-.
Necessary to make string literals from the first one end up at their
correct positions in the data segment even after the upcoming
deduplication…
Part of P0076, funded by [Anonymous] and -Tom-.
Oh hey, guarding declarations with complicated types via #ifdef limits
the header files we additionally have to #include!
Part of P0076, funded by [Anonymous] and -Tom-.
The TH04/TH05 BGM/SE mode setup is a good example for code where
different structure field offsets will vanish completely upon reverse-
engineering. If we continued to use the per-game ID string as the
variable name, we'd only have another game-specific "difference" there.
Part of P0065, funded by Touhou Patch Center.
So many things named `score_*`, so many things named `hiscore_*`…
Let's go with `scoredat_*`, which clearly indicates that this stuff is
saved into a file, while still being only 8 characters.
Part of P0063, funded by -Tom-.
At least wherever Turbo C++ and master.lib want us to use a
non-pointer, since both use uint16_t for segment values throughout
their APIs instead of the more sensible void __seg*. Maybe, integer
arithmetic on segment values was widely considered more important than
dereferencing?
This, hands down, has been the single worst stretch of decompilation so far.
Three extremely difficult functions that each still required inline assembly.
And no, this didn't even work out with any of the optimization features in
Borland C++ that aren't included in Turbo C++.
nmlgc