Commit Graph

18 Commits

Author SHA1 Message Date
nmlgc 47e5601613 [Reverse-engineering] [th03/th04/th05] Frame-count-mod-2/4/8/16 globals
Mostly used for animations, but NOPping out the assignments causes
Ultra-like behavior in some (mid)bosses, at least in TH04 and TH05?

Funded by -Tom-.
2018-04-16 13:18:54 +02:00
nmlgc 4b8baf1413 [Reverse-engineering] [th02/th03/th04/th05] Random number ring buffer
Yes, you're reading that correctly. If the cursor is at 255, reading a
16-bit value will fill the upper 8 bits with the neighboring cursor
value, which always is 0xFF.

Funded by -Tom-.
2018-03-16 18:12:21 +01:00
nmlgc 39c169c30d [Reduction] Separate functions for 1D and 2D vector construction
Look at that TH05 vector2_at_opt function. What the hell, the caller is
supposed to set up the stack frame for the function? How do you even get
a compiler to do this (and no, I haven't found a compiler switch)? No
way around writing a separate "optimizer" as part of the compilation
pipeline, it seems.
2017-01-08 21:01:13 +01:00
nmlgc 6759d346d5 [Reduction] Lookup table for horizontally flipping planar pixels
OK, let's not identify the arrays in a file-based fashion just yet, and
first reduce all shared ZUN code that uses arrays. Less stressful, we'll
have to do this anyway, and I just can't resist the urge to immediately
reverse-engineer everything I find.
2017-01-07 22:30:46 +01:00
nmlgc 43001161e3 [Maintenance] Fix any whitespace issues in our own code 2015-09-07 15:44:48 +02:00
nmlgc de491f225d [Maintenance] Move the sound driver function slices from hardware/ to snd/
And renaming them all to the short filenames they will be decompiled to for
consistency. These functions aren't really immediately hardware-related, as
we've established earlier in the decompilation.
2015-03-15 23:01:31 +01:00
nmlgc 92979e8f31 [C decompilation] [th02] Code segment #2 of all three executables
Only one code segment left in both OP and FUUIN! its-happening.gif

Yeah, that commit is way larger than I'm comfortable with, but none of these
functions is particularly large or difficult to decompile (with the exception
of graph_putsa_fx(), which I actually did weeks ago), and OP and MAIN have
their own unique functions in between the shared ones, so…
2015-03-14 23:25:50 +01:00
nmlgc 404044f32b [C decompilation] [th02/op] [th03/op] [th04/op] Frame delay #1 2015-03-04 02:47:16 +01:00
nmlgc 22332a71fa Make all sound functions and variables available to C 2015-02-23 18:28:38 +01:00
nmlgc 46eb3792cf Move frame_delay into the hardware/ subdirectory 2015-02-23 10:29:12 +01:00
nmlgc 6d8ff6b72e Make previously reduced ZUN functions available to C 2015-02-21 14:12:22 +01:00
nmlgc 2cac434455 [Reverse-engineering] Sound effect playback 2015-02-13 12:56:51 +01:00
nmlgc a07e5fad42 [Reverse-engineering] Slot-based PI display
Also covering the two variations for blitting only every second row or
blitting only a 320x200 quarter, as seen in the endings.

So yeah, there's indeed nothing wrong with piread.cpp. TH03 just uses that
separate function that only blits every second row of an image, and indeed
always loads the entire image as it would appear in a PNG conversion. Here's
what happens if you display these images using the non-interlacing function:
https://www.dropbox.com/s/885krj09d9l0890/th03%20PI%20no%20interlace.png
2014-12-18 14:36:43 +01:00
nmlgc bead27b781 Use TASM calling convention syntax for previously identified ZUN functions
With TH03 changing the calling convention for most of the code from __cdecl to
__pascal, I've been getting more and more confused about this myself. So,
let's settle on the following consistent syntax for function calls:

* C where the calling convention is actually __cdecl and where TASM's emitted
  __cdecl code matches the original binary
* PASCAL where the calling convention is actually __pascal
* STDCALL where the calling convention is actually __cdecl, but where
  the caller either defers stack cleanup (summing up the stack size of
  multiple functions, then cleaning it all in a single "add sp" instruction)
  or where the stack is cleared in a different way (e.g. "pop cx").

Unfortunately though, when using the ARG directive to automatically generate
an appropriate RET instruction for the given calling convention, TASM always
emits ENTER and LEAVE instructions even when no local variables are declared,
which greatly limits the number of functions where we can use that syntax. -.-
2014-12-16 05:53:56 +01:00
nmlgc f40819b0e5 [Reverse-engineering] frame_delay 2014-11-23 22:32:26 +01:00
nmlgc b532a96c7e [JWasm move] Avoid "push large"
For 32-bit immediate values, PUSH by itself is enough. For everything else,
PUSHD works in both TASM and JWasm.

Also, could it be...? Could we actually move to JWasm without breaking the
build in TASM at all?
2014-11-19 12:09:22 +01:00
nmlgc b4361e8487 [Reduction] #700-704: pfopen
... and then I end up copying modified versions into the individual game
subdirectories after all, because the changes between games were simply too
drastic. (That's also why I'm counting pfopen() itself twice.)

Only one slice left now, and then we're done with reduction!
2014-11-17 04:54:40 +01:00
nmlgc f303222ffc Replace MASTERMOD with a per-game constant
Yup, packfiles finally proved that we really have a different set of changes
to master.lib in every game. Also, there are bound to be more of these game-
specific small changes to otherwise identical code in ZUN's own code.

And hey, no need to define that value in the build scripts anymore.

(I've also considered just copying modified versions into the individual game
subdirectories, but it's not too nice to expect people to diff them in order
to actually understand why these copies exist and where the changes actually
are.)
2014-11-15 02:03:41 +01:00