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
The special case doesn't appear to make a significant difference in any games, and the current implementation has a (minor, fixable) issue that breaks Super Mario Sunshine (both with a failed assertion (https://bugs.dolphin-emu.org/issues/11742) and a rendering issue (https://bugs.dolphin-emu.org/issues/7476)). Hardware testing wasn't able to reproduce the special case, either, so it may just not exist.
PR #9315 contains a fixed implementation of the special case on all video backends, and can serve as a basis for it being reintroduced if it is found to exist under more specific circumstances. For now, I don't see a reason to keep it present.
-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.
The name was confusing as changing it at runtime would not change the window to fullscreen, as it effectively only affects the start of the emulation.
Also blocked the ability to change it when the emulation is running, to be more inline with other similar settings, like "Render to main Window".
Also provides operator!= for logical symmetry.
We can also take the arguments by value, as the arguments are trivially
copyable enum values which fit nicely into registers already.
https://bugs.dolphin-emu.org/issues/6749
This change fixes the scratchy audio in Teenage Mutant Ninja Turtles (SX7E52/SX7P52). The game starts an audio interface DMA with an unaligned address, and because Dolphin was not masking off the low 5 bits of AUDIO_DMA_START_LO, all future AI DMAs were misaligned. To understand why, it is instructive to refer to AUDIO_InitDMA() in libogc, which behaves the same as the official SDK:
_dspReg[25] = (_dspReg[25]&~0xffe0)|(startaddr&0xffff);
The implementation does not mask off the low bits of the passed in value before it ORs them with low bits of the current register value. Therefore, if they are not masked off by the hardware itself, they become permanently stuck once set.
Adding a write mask for AUDIO_DMA_START_LO is enough to fix the bug in TMNT, but I decided to run some tests on GC and Wii to find the correct write masks for the surrounding registers, as only a couple were already being masked. Dolphin has gotten away with not masking the rest because many are already A) masked on read (or never read) by the SDK and/or B) masked on use (or never used) in Dolphin.
This leaves just three registers where the difference may be observable: AR_DMA_CNT_H and AUDIO_DMA_START_HI/LO.
operator[] performs a default construction if an object at the given key
doesn't exist before overwriting it with the one we provide in operator=
insert_or_assign performs optimal insertion by avoiding the default
construction if an entry doesn't exist.
Not a game changer, but it is essentially a "free" change.
Allows lookups to be done with std::string_view or any other string
type. This allows for non-allocating strings to be used with the name
lookup without needing to construct a std::string.
