This fixes a problem I was having where using frame advance with the
debugger open would frequently cause panic alerts about invalid addresses
due to the CPU thread changing MSR.DR while the host thread was trying
to access memory.
To aid in tracking down all the places where we weren't properly locking
the CPU, I've created a new type (in Core.h) that you have to pass as a
reference or pointer to functions that require running as the CPU thread.
In a code block where a guest register is accessed at least twice and the
last access is a write and the register is not discardable immediately
after the second-to-last instruction (perhaps there is an instruction
in between that can cause an exception), currently Dolphin's JITs will
flush the register after the second-to-last instruction.
It would be better if we replaced the flush after the second-to-last
instruction with a flush that only happens if the exception path is
taken. This change accomplishes that by marking guest registers as
"in use" not just when they are used as inputs but also when they are
used as outputs, preventing the loop in DoJit from flushing the
register until after the last access.
This piece of code is rather hard to understand, but my best guess
at what it's trying to do is that it tries to create opportunities
to skip writing CRs back to ppcState if we know that there are no
CR instructions (or branch instructions, etc) between an instruction
that writes to a CR register and the next blr. This is technically
inaccurate emulation, but as long as games don't do anything too
weird with their ABIs, I suppose it doesn't break anything.
So why do I want to get rid of it? Well, other than breaking some
hypothetical weird game, I imagine it could trip up people trying
to debug a game who are looking at the CR contents. And the code
is just plain confusing. (blr clearly doesn't write to CRs!)
This is done entirely through interpreter fallbacks. It would
probably be possible to implement this using host exception
handlers instead, but I think it would be a lot of complexity
for a rarely used feature, so let's not do it for now.
For performance reasons, there are two settings for this feature:
One setting which does enables just what True Crime: New York City
needs and one setting which enables it all. The latter makes
almost all float instructions fall back to the interpreter.
SPDX standardizes how source code conveys its copyright and licensing
information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX
tags are adopted in many large projects, including things like the Linux
kernel.
When the interpreter writes to a discarded register, its type
must be changed so that it is no longer considered discarded.
Fixes a 62ce1c7 regression.
This commit adds a new "discarded" state for registers.
Discarding a register is like flushing it, but without
actually writing its value back to memory. We can discard
a register only when it is guaranteed that no instruction
will read from the register before it is next written to.
Discarding reduces the register pressure a little, and can
also let us skip a few flushes on interpreter fallbacks.
The output of instructions like fabsx and ps_sel is store-safe
if and only if the relevant inputs are. The old code was always
marking the output as store-safe if the output was a single,
and never otherwise.
Also, the old code was treating the output of psq_l/psq_lu as
store-safe, which seems incorrect (if dequantization is disabled).
Converts the remaining PowerPC code over to fmt-capable logging.
Now, all that's left to convert over are the lingering remnants within
the frontend code.
The idea of this code was to not unroll loops, but it was completely broken.
So we've unrolled all loops, but only up to the second iteration.
Honestly, a better check would test if we branch to code which is already in the compiling block. But this is out of scope for now.
But testing shows that this unrolling actually improve the performance. So instead of fixing this bug, this check can be dropped.
Rather than have a separate independent variable that we need to keep
track of in conjunction with the JIT code buffer size itself, amend the
analyst code to use the code buffer constant in JitBase.
Now if the size ever changes, then the analyst will automatically adjust
to handle it.
This class effectively acted as a "discount vector", that would simply
allocate memory and then delete it in the destructor when it goes out of
scope.
We can just use a std::vector directly to reduce this boilerplate.
PowerPC.h at this point is pretty much a general glob of stuff, and it's
unfortunate, since it means pulling in a lot of unrelated header
dependencies and a bunch of other things that don't need to be seen by
things that just want to read memory.
Breaking this out into its own header keeps all the MMU-related stuff
together and also limits the amount of header dependencies being
included (the primary motivation for this being the former reason).
This fix the awkwardness of having the symbols detection, parsing and loading related logs be in OS HLE while they don't have anything to do with that.
