This is only ever memset to zero and never used again.
This also gets rid of an instance of undefined behavior considering the
draft standard for C++17 (N4659) states at [dcl.type.cv] paragraph 5:
"
The semantics of an access through a volatile glvalue are implementation-defined.
If an attempt is made to access an object defined with a volatile-qualified type
through the use of a non-volatile glvalue, the behavior is undefined.
"
This prevents Dolphin from crashing when the emulated software crashes.
AFAIK, there is absolutely no performance to enabling this with the
x64 JIT.
Eventually, we should probably just remove bMMU
(https://github.com/dolphin-emu/dolphin/pull/1831). We can't do that
yet because of the ARM JIT.
A very basic hardware test shows that the ARMMSG doesn't change until
IOS replies. (People could have disassembled IOS to verify this too...)
Console:
sending request at 00034640 - ARMMSG 133e0fa0
00000000000000000000000000000010(ack) - ARMMSG 133e0fa0
00000000000000000000000000000100(reply) - ARMMSG 00034640
Dolphin, prior to this fix:
sending request (00034640) - ARMMSG 133e0fa0
00000000000000000000000000000011(ack) - ARMMSG 00034640
00000000000000000000000000000100(reply) - ARMMSG 00034640
Dolphin, after this fix:
sending request at 00034640 - ARMMSG 133e0fa0
00000000000000000000000000000011(ack) - ARMMSG 133e0fa0
00000000000000000000000000000100(reply) - ARMMSG 00034640
(Yes, note that the X1 bit is still set. This is a bug that I will
fix in the next commit.)
The IPC interrupt is triggered when IY1/IY2 is set and Y1/Y2 is written
to even when this results in clearing the bit.
This shouldn't change anything in practice but it's a difference
that Dolphin wasn't taking into account, which made me waste some time
when I was writing a hwtest :/
This adjusts IOS IPC timing to be closer to actual hardware:
* Emulate the IPC interrupt delay. On a real Wii, from the point of
view of the PPC, the IPC interrupt appears to fire about 100 TB ticks
after Y1/Y2 is seen.
* Fix the IPC acknowledgement delay. Dolphin was much, much too fast.
* Fix Device::GetDefaultReply to return more reasonable delays. Again,
Dolphin was way too fast. We now use a more realistic, average reply
time for most requests.
Note: the previous result from https://dolp.in/pr6374 is flawed.
GetTicketViews definitely takes more than 25µs to reply.
The reason the reply delay was so low is because an invalid
parameter was passed to the libogc wrapper, which causes it to
immediately return an error code (-4100).
* Fix the response delay for various replies that come from the kernel:
fd table full, unknown resource manager / device, invalid fd,
unknown IPC command.
Source: https://github.com/leoetlino/hwtests/blob/af320e4/iostest/ipc_timing.cpp
While the code is namespaced out properly, the files weren't separated
into their own directory. This moves the files so that introducing a general
interface is easier in the future for supporting other architectures.
This enables shaders to be compiled while the game is starting, instead
of blocking startup. If a shader is needed before it is compiled,
emulation will block.
This saves us from having to call GetPath when the same file is being
read over and over. (GetPath is more expensive than GetOffset due to
it iterating through parts of the file system and creating strings.)
The original reason I wanted to do this was so that we can replace
the Android-specific code with this in the future, but of course,
just deduplicating between DolphinWX and DolphinQt2 is nice too.
Fixes:
- DolphinQt2 showing the wrong size for split WBFS disc images.
- DolphinQt2 being case sensitive when checking if a file is a DOL/ELF.
- DolphinQt2 not detecting when a Wii banner has become available
after the game list cache was created.
Removes:
- DolphinWX's ability to load PNGs as custom banners. But it was
already rather broken (see https://bugs.dolphin-emu.org/issues/10365
and https://bugs.dolphin-emu.org/issues/10366). The reason I removed
this was because PNG decoding relied on wx code and we don't have any
good non-wx/Qt code for loading PNG files right now (let's not use
SOIL), but we should be able to use libpng directly to implement PNG
loading in the future.
- DolphinQt2's ability to ignore a cached game if the last modified
time differs. We currently don't have a non-wx/Qt way to get the time.
This commit changes devices to always return IPCCommandResult rather
than just a return code for Open() and Close() in order to be able
to better emulate reply timing.
In hindsight, I should have considered we would want to emulate
timing when I cleaned up the device interface, but alas.
This rectifies that mistake.
