Checked on hardware that this bias was not added because I had assumed the other way around would be true, forgot to ask about making a PR for this when I initially had done so
If we're on an x64 CPU that doesn't have the MOVBE extension, trying to
SwapAndStore a host register results in that register's value getting
clobbered with the swapped value. Jit64::stX and Jit64::stXx detect this
case, and if necessary, emit a MOV to a register that's fine to clobber.
This logic was broken by the merge of PR 12134. Jit64::stX and
Jit64::stXx were assuming that if RegCache::IsImm returns true for a
guest register, calling RegCache::Use or RegCache::BindOrImm for that
guest register would result in an immediate. However, PR 12134 made it
possible for a guest register to have both a host register and an
immediate in the register cache at the same time. When this happens,
RegCache::IsImm returns true, yet RegCache::Use and RegCache::BindForImm
return an RCOpArg whose Location returns a host register. (To make it
extra confusing, RCOpArg::IsImm calls RegCache::IsImm if the RCOpArg
came from RegCache, so RCOpArg::IsImm returns true!)
To fix this, in cases where Jit64::stX and Jit64::stXx explicitly need
an immediate to avoid having to emit an extra MOV, let's call
RegCache::Imm32 so that we're certain that we're getting an immediate.
This fixes an issue on older x64 CPUs that manifested as e.g. completely
broken graphics in Spyro: Enter the Dragonfly.
The constant propagation PR made it so that a guest register can be
present in the register cache as both a host register and an immediate
at the same time. If such a guest register is requested from the
register cache, the register cache prefers returning it as a host
register. However, RCOpArg::IsImm still returns true in this case. This
is confusing, especially since OpArg::IsImm does not return true if the
RCOpArg is converted into an OpArg.
This commit makes RCOpArg::IsImm check whether RCOpArg::Location returns
an immediate, so that RCOpArg::IsImm returns false when a host register
is being used. Code that wants to know whether an immediate exists in
the register cache rather than whether an immediate is currently being
used should call RegCache::IsImm instead.
Recently came across a strange issue where Dolphin would hard crash in most games with this error:
```sh
/usr/include/c++/15.2.1/optional:1165: constexpr const _Tp* std::optional<_Tp>::operator->() const [with _Tp = InputCommon::ImagePixelData]: Assertion 'this->_M_is_engaged()' failed.
```
The culprit turned out to be accessing `host_key_image` which is an `std::optional` thay may return `std::nullopt`. I'm not sure why this issue started occuring for me since I've had no issue with my Dynamic Input Textures in the past? But this fixes a crash if the image fails to load.
JMC47
JosJuice
LillyJadeKatrin
Sintendo
OatmealDome
Filippo Tarpini
Admiral H. Curtiss
Jordan Woyak
Anarky
Craig Carnell
Tillmann Karras
Joshua Vandaële
cristian64
Nuh Uh