In the unit test I'm adding in the next commit, I want to call
MemoryManager::Init, but initializing all the hardware that
MemoryManager::InitMMIO calls into would be cumbersome.
Calling MemoryManager::InitMMIO from MemoryManager::Init was a bit
strange anyway. Because MemoryManager::Init is called about halfway
through HW::Init, some of the hardware that MemoryManager::InitMMIO
calls into isn't initialized yet.
Most systems that Dolphin runs on have a page size of 4 KiB, which
conveniently matches the page size of the GameCube and Wii. But there
are also systems that use larger page sizes, notably Apple CPUs with
16 KiB page sizes. To let us create host mappings on such systems, this
commit implements combining guest mappings into host page sized mappings
wherever possible.
For this to work for a given mapping, not only do four (in the case of
16 KiB) guest mappings have to exist adjacent to each other, but the
corresponding translated addresses also have to be adjacent, and the
lowest bits of the addresses have to match. When I tested a few games,
the following percentages of guest mappings met these criteria:
Spider-Man 2: 0%-12%
Rogue Squadron 2: 39%-42%
Rogue Squadron 3: 28%-41%
So while 16 KiB systems don't get as much of a performance improvement
as 4 KiB systems, they do still get some improvement.
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 I also took the opportunity to move
some other members around 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.
It turns out that it is possible to create a login alias in RetroAchievements
such that you can log in with a username that doesn't match your display name.
AchievementManager was treating this as a synchronization error, but this is
desired behavior, so this removes the check.
Yellow squiggly lines begone!
Done automatically on .cpp files through `run-clang-tidy`, with manual corrections to the mistakes.
If an import is directly used, but is technically unnecessary since it's recursively imported by something else, it is *not* removed.
The tool doesn't touch .h files, so I did some of them by hand while fixing errors due to old recursive imports.
Not everything is removed, but the cleanup should be substantial enough.
Because this done on Linux, code that isn't used on it is mostly untouched.
(Hopefully no open PR is depending on these imports...)
If all inputs to an fmadds instruction (including cousins like fmsubs,
fnmadd...) are single-precision, then the result is identical between a
double-precision calculation with an error-free transform (whether the
calculation is fused or not) and a single-precision FMA instruction
(must be fused). So as a performance optimization in JitArm64, if we
were going to use double precision with EFT but the inputs are singles,
instead we'll use a normal single-precision FMA instruction without
anything extra. This lets us skip both the EFT and double-to-single
conversions.
Also renaming `inaccurate_fma` to `nonfused` because it's confusing that
`inaccurate_fma` and `m_accurate_fmadds` have such similar names
despite controlling separate things.
If result_reg is set to a temporary register instead of VD because of
accurate NaNs, there's no need to allocate a secondary temporary
register because of inaccurate FMA.
When we're emulating single-precision FMA using an FMA instruction,
there's no precision benefit from using a double-precision instruction,
assuming all inputs are single-precision. But when we're emulating
single-precision FMA using separate multiplication and addition
instructions, there is.
This change increases the precision of inaccurate FMA to the same level
as Jit64, which matters since the only reason we have the inaccurate
FMA mode is for sync compatibility with Jit64.
JosJuice