Removing and readding every page table mapping every time something
changes in the page table is very slow. Instead, let's generate a diff
and ask Memmap to update only the diff.
Page table mappings are only used when DR is set, so if page tables are
updated when DR isn't set, we can wait with updating page table mappings
until DR gets set. This lets us batch page table updates in the Disney
Trio of Destruction, improving performance when the games are loading
data. It doesn't help much for GameCube games, because those run tlbie
with DR set.
The PowerPCState struct has had its members slightly reordered. I had to
put pagetable_update_pending less than 4 KiB from the start so AArch64's
LDRB (immediate) can access it, and that gave me an opportunity to move
around some other members to cut down on padding.
Previously we've only been setting up fastmem mappings for block address
translation, but now we also do it for page address translation. This
increases performance when games access memory using page tables, but
decreases performance when games set up page tables.
The tlbie instruction is used as an indication that the mappings need to
be updated.
There are some accuracy downsides:
* The TLB is now effectively infinitely large, which matters if games
don't use tlbie when modifying page tables.
* The R and C bits for page table entries get set pessimistically rather
than when the page is actually accessed.
No games are known to be broken by these inaccuracies, but unfortunately
the second inaccuracy causes a large performance regression in Rogue
Squadron 3. You still get the old, more accurate behavior if Enable
Write-Back Cache is on.
For thread safety, we shouldn't return any pointers or references that
can be used to mutate the state of the PPCSymbolDB. This should be the
final part of making PPCSymbolDB thread safe unless I've missed
something.
9395238 added locking in some PPCSymbolDB functions that access member
variables, but far from all. To ensure thread safety, this commit adds
the missing locking.
9395238 added a mutex to PPCSymbolDB, and made functions return with an
"empty" result if called while the mutex is locked. This new behavior
has the potential to affect not only less important call sites like the
symbol printing mentioned in a comment, but also the JIT deciding if it
should HLE a function.
A later commit in this pull request decreases the amount of lock
contention, reducing the performance impact of this commit.
When Android sends Dolphin to the background, emulation *must* pause,
otherwise emulation continues running and continues outputting audio to
the user. RetroAchievements mustn't be allowed to override it.
The SetDisc function calls AchievementManager::LoadGame with the game's
volume. Calling AchievementManager::LoadGame again afterwards with
nullptr prevents RetroAchievements from working.
