mirror of
https://github.com/zeldaret/oot.git
synced 2024-12-03 16:26:17 +00:00
5785c7adfb
* Move built roms to build directory, along with rename map and linker script * PR review * sym_info fix * Revert docs/tutorial/data.md change
126 lines
4.2 KiB
Markdown
126 lines
4.2 KiB
Markdown
# Decompiling retail versions
|
|
|
|
The next decompilation target for OOT is the PAL GameCube Master Quest ROM
|
|
(`gc-eu-mq`), because it is the retail version that is most similar to the Debug
|
|
ROM. Unfortunately there are still a lot of differences, many of which are
|
|
register or stack allocation differences because retail ROMs were built with
|
|
different compiler flags. However, once this version is done, future
|
|
retail versions should be much easier, as the changes between retail versions are
|
|
small in comparison.
|
|
|
|
Instead of `cp`ing a matching build into `expected/`, the target ROM is disassembled as `.s` files then
|
|
reassembled as `.o` files directly into `expected/build/gc-eu-mq` for diff tools.
|
|
This allows us to make progress matching code in parallel with solving other
|
|
problems (such as the build system, ROM organization, and BSS ordering). The
|
|
files in `tools/disasm/gc-eu-mq` say how to split the source files and where the
|
|
functions and variables are in the target ROM, and these may need to be updated
|
|
if there are mistakes or if function names change due to documentation work.
|
|
|
|
Unfortunately, the disassembly is not perfect, so a "correct" decompilation might
|
|
still show diffs with data symbols. We might improve this later, but these data
|
|
diffs are fine to ignore for now.
|
|
|
|
For register and stack allocation differences, often the code can be tweaked so
|
|
that it matches both the retail ROM while continuing to match the Debug ROM (for
|
|
example, by reordering assignments or moving a local variable declaration inside
|
|
an `if` block). Since retail MM versions use the same compiler flags as retail
|
|
OOT, checking MM decomp for similar code can help.
|
|
|
|
We can disable code that was removed in retail builds by adding
|
|
`#if OOT_DEBUG ... #endif` or `if (OOT_DEBUG) { ... }` around these parts of the
|
|
code. In order to keep the code readable, we should try to minimize the amount of
|
|
`#if` noise whenever possible.
|
|
|
|
## Setup
|
|
|
|
1. Copy your target PAL GameCube Master Quest ROM (non-debug) to
|
|
`baseroms/gc-eu-mq/baserom.z64`
|
|
|
|
1. Extract assets and ROM files **from the Debug ROM** by running
|
|
|
|
```sh
|
|
make setup -jN
|
|
```
|
|
|
|
if necessary, where `N` is the number of cores on your machine.
|
|
|
|
1. Build the non-matching test ROM by running
|
|
|
|
```sh
|
|
make setup -jN VERSION=gc-eu-mq
|
|
make -jN VERSION=gc-eu-mq
|
|
```
|
|
|
|
where `N` is the number of cores on your machine. This will build into
|
|
`build/gc-eu-mq` and produce `build/gc-eu-mq/oot-gc-eu-mq.z64`.
|
|
|
|
If you later want to delete all output files, run
|
|
|
|
```sh
|
|
make clean VERSION=gc-eu-mq
|
|
```
|
|
|
|
1. Disassemble the target ROM by running
|
|
|
|
```sh
|
|
make disasm -jN VERSION=gc-eu-mq
|
|
```
|
|
|
|
where `N` is the number of cores on your machine. The outputs will be written to
|
|
`expected/build/gc-eu-mq`.
|
|
|
|
Note that if you need to copy a matching build for the Debug ROM, you can use
|
|
|
|
```sh
|
|
mkdir -p expected/build
|
|
cp -r build/gc-eu-mq-dbg expected/build
|
|
```
|
|
|
|
to avoid clobbering the disassembly.
|
|
|
|
## Diff Tools
|
|
|
|
Note that many tools will require activating the Python virtual environment
|
|
in your terminal session. To do this, run:
|
|
|
|
```sh
|
|
source .venv/bin/activate
|
|
```
|
|
|
|
### retail_progress.py
|
|
|
|
Running `./retail_progress.py path/to/file.c` will attempt to figure out which functions
|
|
in a file still need to match for `gc-eu-mq`. To get an overview of diffs for
|
|
all files, run `./retail_progress.py` with no arguments.
|
|
|
|
### asm-differ / diff.py
|
|
|
|
To diff assembly for a single function in `gc-eu-mq`, run e.g.
|
|
|
|
```sh
|
|
./diff.py -mwo3 -v gc-eu-mq Math3D_CylTriVsIntersect
|
|
```
|
|
|
|
The `-v` flag tells `diff.py` to compare between `build/gc-eu-mq` and
|
|
`expected/build/gc-eu-mq`, and to use `make VERSION=gc-eu-mq` when rebuilding.
|
|
|
|
You may also want to diff the Debug ROM in another terminal with
|
|
|
|
```sh
|
|
./diff.py -mwo3 Math3D_CylTriVsIntersect
|
|
```
|
|
|
|
to ensure any changes still match there.
|
|
|
|
### Permuter and decomp.me
|
|
|
|
Disassembly for individual functions is written to
|
|
`expected/build/gc-eu-mq/functions`, so to get a [decomp.me](https://decomp.me/) scratch you can run
|
|
e.g.
|
|
|
|
```sh
|
|
decomp-permuter/import.py \
|
|
src/code/sys_math3d.c \
|
|
expected/build/gc-eu-mq/functions/src/code/sys_math3d/Math3D_CylTriVsIntersect.s \
|
|
VERSION=gc-eu-mq --decompme
|
|
```
|