… Wow, the orb is *actually* only ever displayed at byte-aligned X
coordinates, divisible by 8. It's only thanks to the constant spinning
that its movement appears at least *somewhat* smooth.
(And yeah, this is purely a rendering issue; internally, its position
*is* tracked at pixel precision.)
Part of P0097, funded by Ember2528.
So even TH01 wasn't 100% C++ after all. Turns out that this function
was the only instance in all of REIIDEN.EXE where ReC98 previously had
different encodings for identical x86 instructions.
Part of P0096, funded by Ember2528.
Surprise, it's the (terribly suboptimal) setgsta() example function
from the PC-9801 Programmers' Bible! 100% identical, so ZUN must have
read that book as well.
Used for screen shaking effects, as well as the scrolling backgrounds
at the start of the Final Boss stages.
Completes P0095, funded by Yanga.
It's actually not that easy to find memory references in REIIDEN.EXE
that can both be quickly be RE'd at the end of a push, and which also
aren't more sensibly handled by immediate decompilation. So, have more
false positive busywork…
Part of P0095, funded by Yanga.
No idea why ZUN split the 6 slots into 4 with a regular alpha plane,
and 2 with a negated alpha plane. The latter are only used for Sariel's
animations.
Part of P0095, funded by Yanga.
100% PI for both! Now, where are all the modders who wanted to replace
MDRV2 with PMD… because you can now prototype that, without worring
about x86 instruction lengths, at least inside the main menu.
Part of P0095, funded by Yanga.
> "Sure, this is a PI push, but this second-to-last set of PI false
positives so small, let's immediately decompile it ^.^"
> Time taken: 22 minutes
Nice when this works out!
Part of P0095, funded by Yanga.
Too bad we still have to bother with renaming the function via #define
in the few cases where an executable contains two or more copies of
this function. We can't just make it `static`, since TH02 MAINE.EXE
actually does far-call it from a different segment (and thus,
translation unit).
Part of P0094, funded by Yanga.
The REIIDEN.EXE version (which is only shown when game-overing) has a
completely invisible timeout that force-enters a high score name after
1000... *keyboard inputs*? Not frames? Why. Like, how do even you
realistically to such a number.
(Best guess: It's a hidden easter egg to amuse players who place
drinking glasses on cursor keys. Or beer bottles.)
And hey, that initialization of the name variable with ASCII spaces.
The only actually meaningful byte-wise access… except that it's not,
because ZUN could have just used the Shift-JIS ideographic space for
the exact same effect.
Completes P0093, funded by Ember2528.
Now with POSIX file I/O in both executables. And the confirmation that
the name array is indeed exclusively accessed per-byte.
Part of P0093, funded by Ember2528.
It's exactly as terrible as you would have expected after hearing
"alphabet cursor actually stored as on-screen position". Nothing gained
in reducing redundancy any further here, any meaningful change would
pretty much have to rewrite the entire thing.
Part of P0093, funded by Ember2528.
In which inline functions are apparently the only way to trick Turbo
C++ into not actually optimizing away the useless `AND AL, 0FFh`.
But come on. Just accessing the high score name characters in chunks of
16-bit Shift-JIS codepoints (which is what they are!) instead of
breaking them down to bytes *everywhere* would have been both more
readable (no swapping of Shift-JIS literals, no bitshifts), more
efficient (this isn't running on an 8-bit CPU after all), and less of a
waste of my time…
Completes P0092, funded by Yanga.
Lol, the internal alphabet cursor position is actually stored as the
on-screen top-left position of the selected character, which this
function then maps back to a character index. At least that gets rid of
quite a bunch of PI false positives now.
Part of P0092, funded by Yanga.
With ternary operator expressions straight out of Jigoku.
(TL note: Jigoku means hell.)
Nice to see that Turbo C++ apparently has no nesting limit on function
call inlining in general, though!
Part of P0092, funded by Yanga.
The only TH01 executable not supporting the numpad?
And that's the point where you just rewrite the distinct input_prev_*
values as a single array, because they're local to input_sense()
anyway.
Part of P0091, funded by Ember2528.
Yes, TH01's memory info screen will recurse into itself for every 3
frames the PgUp key is held, requiring one additional PgDown press per
recursion to actually get out of it.
You can, of course, also crash the system via a stack overflow this
way, if that's your thing.
Part of P0091, funded by Ember2528.
Of which we can express precisely *nothing* as an inline function,
because Turbo C++ always emits a useless `JMP SHORT $+2` at the end of
such an inlined function if it contains nested `if` statements. This is
also what forced some of the functions in 90252cc to be expressed as
macros. By now, this is clear enough to be documented separately.
And to warrant this separate commit.
Completes P0090, funded by Yanga.
Starting with the odd one out, the one that doesn't use master.lib and
has two input sense functions: one for the main menu, and one for the
option window.
Both of which also immediately perform the ring arithmetic on the menu
cursor variable… because there's nothing else to be done with these
inputs in OP.EXE? Separating input sensing from processing apparently
wasn't all too obvious of a thought, and it's only truly done in TH02
and later.
Part of P0090, funded by Yanga.
That's… pretty specific. The only thing on the main menu with this
color is the "1996 ZUN" text at the bottom… probably part of an
effect that we never got to see. Every other idea would be baseless
speculation, given that the snapped buffer isn't used anywhere else.
Part of P0090, funded by Yanga.
Otherwise, TASM would simply convert all EXTRN declarations in those
files to uppercase. Then, the linker would expect them in uppercase,
forcing both the case-sensitive big 32-bit .ASM files *and* the entire
C land to declare them as uppercase as well.
For functions with __pascal convention which are always uppercased
anyway, this makes no difference. It does matter for regular __cdecl
variables, though, and the C declaration of [score_delta] in e6294c2
already showed that we'd then be forced to use macros if we wanted to
pretend that these names still had lowercase characters.
Doing this for every variable referenced in both C land and 16-bit ASM
land gets annoying quickly. So, no need to force this inconsistency if
we can get rid of it by slightly uglifying ASM land.
Part of P0089, funded by [Anonymous] and Blue Bolt.
tiles_invalidate_around() must have had the hardest function signature
to figure out in all of PC-98 Touhou… because it seems impossible to
handle all three ways of passing parameters. No way around separately
declaring it in every translation unit then, with the parameter list
expected by that segment's code generation.
Part of P0089, funded by [Anonymous] and Blue Bolt.
A bit tricky with those ASM translation units near-calling functions in
the very first segment, and #pragma codeseg requiring an additional
group parameter to correctly calculate array offsets (including those
used for `switch` statements). But doable.
Part of P0089, funded by [Anonymous] and Blue Bolt.
nmlgc