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| author | cristian64 <cristian64@gmail.com> | 2026-03-27 11:30:52 +0000 |
|---|---|---|
| committer | cristian64 <cristian64@gmail.com> | 2026-07-11 23:02:54 +0100 |
| commit | 24ad5628717df1184fcbac027cd27618891afc40 (patch) | |
| tree | 1850c0898a36bb4376204701665426bd3418f223 /Source/Core/DiscIO/VolumeDisc.cpp | |
| parent | 6de526c684ee6dd8b6fc3447dae858ae480ccbb5 (diff) | |
Core: Add `Volume::GetSimulatedMemorySize()`.
The data structure of the `bi2.bin` file in which the simulated memory
size is set:
> **13.2 Disk header Information**
>
> this is loaded to the Address in `0x800000f4` when a disc is initialized by the IPL
>
> | offset | end | size | Description |
> | :------: | --- | :--: | --------------------- |
> | `0x0000` | | 4 | Debug-monitor Size |
> | `0x0004` | | 4 | Simulated Memory Size |
> | `0x0008` | | 4 | Argument offset |
> | `0x000c` | | 4 | Debug flag |
> | `0x0010` | | 4 | Track Location |
> | `0x0014` | | 4 | Track size |
> | `0x0018` | | 4 | Countrycode |
> | `0x001c` | | 4 | ? |
See https://hitmen.c02.at/files/yagcd/yagcd/chap13.html#sec13.2.
Most GameCube games set the value to `24 MiB`, which matches the
physical memory size. Most Wii games set the value to `0 MiB` (unset).
The debug build of _Mario Kart: Double Dash!!_ is one game that sets the
value to `48 MiB`.
Diffstat (limited to 'Source/Core/DiscIO/VolumeDisc.cpp')
| -rw-r--r-- | Source/Core/DiscIO/VolumeDisc.cpp | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/Source/Core/DiscIO/VolumeDisc.cpp b/Source/Core/DiscIO/VolumeDisc.cpp index e842540376..4dd16c4cef 100644 --- a/Source/Core/DiscIO/VolumeDisc.cpp +++ b/Source/Core/DiscIO/VolumeDisc.cpp @@ -179,6 +179,14 @@ std::optional<u8> VolumeDisc::GetDiscNumber(const Partition& partition) const return ReadSwapped<u8>(6, partition); } +u32 VolumeDisc::GetSimulatedMemorySize() const +{ + // Simulated memory size is a 32-bit unsigned integer in the `bi2.bin` file at offset `0x04`. + // Apploader reads this and "simulates" a smaller memory size. Originally useful for simulating + // 24 MiB of memory on devkits with 48 MiB. + return ReadSwapped<u32>(BI2_ADDRESS + 0x04, GetGamePartition()).value_or(0); +} + bool VolumeDisc::IsNKit() const { constexpr u32 NKIT_MAGIC = 0x4E4B4954; // "NKIT" |