EmulationActivity has an instance of Settings. If you go to
SettingsActivity from EmulationActivity and change some settings,
the changes get saved to disk, but EmulationActivity's Settings
instance still contains the old settings in its map of all
settings (assuming the EmulationActivity was not killed by the
system to save memory). Then, once you're done playing your
game and exit EmulationActivity, EmulationActivity calls
Settings.saveSettings. This call to saveSettings first overwrites
the entire INI file with its map of all settings (which is
outdated) in order to save any legacy settings that have changed
(which they haven't, since the GUI doesn't let you change legacy
settings while a game is running). Then, it asks the new config
system to write the most up-to-date values available for non-legacy
settings, which should make all the settings be up-to-date again.
The problem here is that the new config system would skip writing
to disk if no settings changes had been made since the last time
we asked it to write to disk (i.e. since SettingsActivity exited).
NB: Calling Settings.loadSettings in EmulationActivity.onResume
is not a working solution. I assume this is because
SettingsActivity saves its settings in onStop and not onPause.
FinalizeCarryOverflow didn't maintain XER[OV/SO] properly due to an
oversight. Here's the code it would generate:
0: 9c pushf
1: 80 65 3b fe and BYTE PTR [rbp+0x3b],0xfe
5: 71 04 jno b <jno>
7: c6 45 3b 03 mov BYTE PTR [rbp+0x3b],0x3
000000000000000b <jno>:
b: 9d popf
At first glance it seems reasonable. The host flags are carefully
preserved with PUSHF. The AND instruction clears XER[OV]. Next, an
conditional branch checks the host's overflow flag and, if needed, skips
over a MOV that sets XER[OV/SO]. Finally, host flags are restored with
POPF.
However, the AND instruction also clears the host's overflow flag. As a
result, the branch that follows it is always taken and the MOV is always
skipped. The end result is that XER[OV] is always cleared while XER[SO]
is left unchanged.
Putting POPF immediately after the AND would fix this, but we already
have GenerateOverflow doing it correctly (and without the PUSHF/POPF
shenanigans too). So let's just use that instead.
Happens in Super Mario Sunshine. You could probably do something similar
for b == -1 (like we do for subfic), but I couldn't find any titles that
do this.
- Case 1: d == a
Before:
41 8B C7 mov eax,r15d
41 BF 00 00 00 00 mov r15d,0
44 2B F8 sub r15d,eax
After:
41 F7 DF neg r15d
- Case 2: d != a
Before:
BF 00 00 00 00 mov edi,0
41 2B FD sub edi,r13d
After:
41 8B FD mov edi,r13d
F7 DF neg edi
Consider the case where d and a refer to the same PowerPC register,
which is known to hold an immediate value by the RegCache. We place a
ReadWrite constraint on this register and bind it to an x86 register.
The RegCache then allocates a new register, initializes it with the
immediate, and returns a RCX64Reg for both d and a.
At this point information about the immediate value becomes unreachable.
In the case of subfx, this generates suboptimal code:
Before 1:
BF 1E 00 00 00 mov edi,1Eh <- done by RegCache
8B C7 mov eax,edi
8B FE mov edi,esi
2B F8 sub edi,eax
Before 2:
BE 00 AC 3F 80 mov esi,803FAC00h <- done by RegCache
8B C6 mov eax,esi
8B 75 EC mov esi,dword ptr [rbp-14h]
2B F0 sub esi,eax
The solution is to explicitly handle the constant a case before having
the RegCache allocate registers for us.
After 1:
8D 7E E2 lea edi,[rsi-1Eh]
After 2:
8B 75 EC mov esi,dword ptr [rbp-14h]
81 EE 00 AC 3F 80 sub esi,803FAC00h
-If adding 2 devices with the same name, they their unique id wouldn't be increased, causing a conflict.
-Removing a device wouldn't actually remove it from the internal devices list because the list of devices had already been updated when going through it.
-It was possible to remove devices belonging to other sources by adding a device with the same name and then removing it.
