TDW and TCR modes share the same bit in the GRCG mode register and are
thus indistinguishable when looking at a disassembly, but only apply to
writing (TDW) or reading (TCR), respectively. TH01 only performs read
operations in this mode, so it's unambiguously TCR.
Part of P0176, funded by Ember2528.
TH01 doesn't use "back" and "front" pages in the way the later games
do, after all. Indicating that the source page of this parameter-less
function is the one that was previously set via graph_accesspage_func()
is going to make pretty much all its call sites way clearer, and stops
implying any further state.
Part of P0167, funded by Ember2528.
This gets rid of a couple of per-entity sprite bitplane types, makes
sprite declarations easier to read by putting width and height next to
each other… and points out a number of array dimension mistakes -.-
Even in places where we can't use it.
Part of P0138, funded by [Anonymous] and Blue Bolt.
It's not necessary for assigning `__seg` pointers to `far` ones, which
might even remove the <dos.h> dependency in some translation units.
Part of P0134, funded by [Anonymous].
Rather than preferring either the Microsoft/Watcom `(in|out)pw?` style,
or the Borland `(in|out)portb?` style, master.lib had to introduce its
own `(OUT|IN)P[BW]` naming scheme… Insert obligatory xkcd standards
comic.
Part of P0126, funded by [Anonymous] and Blue Bolt.
And get rid of the constraining FX() macro, with its spacing parameter
that we haven't even seen used so far.
Part of P0124, funded by [Anonymous] and Blue Bolt.
Not only getting rid of the "useless" (and thankfully, consistent)
bitplane parameter, but also allowing those shortened macros to be
redefined for the upcoming little ZUN inconsistency.
Part of P0120, funded by Yanga.
… and this one, while I'm at it. I've been using pretty much every
possible type for VRAM offset variables, depending on my mood that day,
since signedness apparently never matters for those.
Except that it does. And so, just like with most of our high-level
types, we also have to account for ZUN's little signedness
inconsistencies here. Oh well, at least it's now only one of two types,
and there's no need to choose between `int` or `unsigned int` or
`short` or `unsigned short` or `int16_t` or `uint16_t` or `size_t` or…
Part of P0111, funded by [Anonymous] and Blue Bolt.
Whew, time to look at every `int` variable we ever declared! The best
moment to do this would have been a year ago, but well, better late
than never. No need to communicate that in comments anymore.
These shouldn't be used for widths, heights, or sprite-space
coordinates. Maybe we'll cover that another time, this commit is
already large enough.
Part of P0111, funded by [Anonymous] and Blue Bolt.
One fewer magic number. And one more deliberate dependency on a
PC-98-specific hardware constant, to further drive home just how
unportable these games are, even once decompilation will be complete.
Part of P0105, funded by Yanga.
ZUN might have gotten the impression that the EGC can *only* work with
multiples of 16 pixels per load or store? Which might explain why…
Part of P0102, funded by Yanga.
Again, 11 necessary workarounds, vs. forcing byte aligment in at least
18 places, and that number would have significantly grown in the
future.
Part of P0085, funded by -Tom-.
Which actually does inline… in C++, because Turbo C++ doesn't support
the `inline` keyword in C mode. So much for the superiority of that
language, even in 1994…
Part of P0083, funded by Yanga.
I tried `brge` for the latter, but that had *the* most horrible
ergonomics, and I misspelled it as `bgre` 100% of the times I typed it
manually. Turns out that `dots` is also consistent with master.lib's
naming scheme, leaving `planar` to *actually* refer to types storing
multiple planes worth of pixels. These types are showing up more and
more, and deserve something better than their previous long-winded and
misleading name.
Part of P0081, funded by Ember2528.
Just like with the z_text_*() functions, master.lib doesn't already
have graph_init() and graph_exit() either, and once again, ZUN's code
here doesn't fully correspond to any master.lib function. Unlike the
z_text_*() functions though, those names aren't really the best
descriptions for these rather random combinations of BIOS calls and I/O
port writes…
Anyway, that's the entire segment!
Part of P0080, funded by Ember2528 and Splashman.
No macros for the port numbers here! Anyone who will try to read and
understand this code will probably want to look those up in PC-98
hardware documentation, and macros would just be an annoying layer of
indirection then.
Part of P0080, funded by Ember2528 and Splashman.
Page… 2? On a system with only page 0 and 1? Had to get out my real
PC-98 to double-check that I wasn't missing anything here, since
every emulator only looks at the bottom bit of the page number. But
real hardware seems to do the same, and there really is nothing special
to it semantically, being equivalent to page 0. 🤷
Part of P0080, funded by Ember2528 and Splashman.
Allowing us to then retrieve it using a function call with no run-time
cost, although we do have to be careful with the types here.
Also, is that another solution to decompilation puzzles that involve
types of number literals?
Part of P0080, funded by Ember2528 and Splashman.
In which our typedefs mercilessly reveal ZUN's original sloppiness, and
the unncessary sign extension taking place here. Also, ❎ unused…
Completes P0069, funded by [Anonymous] and Yanga.
Yes, when clipping the start and end points to the screen area, ZUN
uses an integer division to calculate the line slopes, rather than a
floating-point one. Doesn't seem like it actually causes any incorrect
lines to be drawn, though; that case is only hit in the Mima boss
fight, which draws a few lines with a bottom coordinate of 400 rather
than 399. It *might* also restore the wrong pixels at parts of the
YuugenMagan fight, causing weird flickering, but seriously, that's an
issue everywhere you look in this game.
Part of P0069, funded by [Anonymous] and Yanga.
TH01's (original) version also replicates the PC-98 text RAM's reverse
and underline attributes. Which was removed in later games,
interestingly and inconsistently enough.
Part of P0068, funded by Yanga.
Including the longest function present in more than one game among all
of PC-98 Touhou, and #23 on the list of longest functions overall,
which draws a 1-pixel line between two arbitrary pixels.
Completes P0067, funded by Splashman.
Semi-unused, that is, the one use of this function doesn't actually
move the rectangle to a different position. Ironically, the non-moving
back-to-front function immediately above *is* unused…
Also, too bad that stack order is the only reason we can't use structs
to combine all plane variables into a single object.
Part of P0067, funded by Splashman.
Previously sloppily mis-RE'd as "some page variable, idk", back in
2015…
Now also with a page number typedef. And yeah, restricting bool to C++
has now proven to be stupid after all.
Part of P0067, funded by Splashman.
nmlgc