CasualPokePlayer

I think this might actually be rather be some prefetch funny business? i.e. the PC is always behind/ahead (depending on your perspective) than what is actually being executed. See https://github.com/TASEmulators/mgba/blob/645282a395aac6d7bbd6f80124517bebbe108e57/include/mgba/internal/arm/isa-inlines.h#L126...

The result of _ARMPCAddress is what's actually compared for the address you pass onto on_bus_exec. Although the instruction actually executed is going to be minus one opcode compared to the...

Exec callback and tracelogger are done at the same point with the same logic, so it's probably related.

For many of those cores/projects, they're checked in as they have been forked and modified, some fairly lightly (e.g. tic80, which mostly just has waterbox interfacing added and minor adjustments...

> placing submodules in /submodules, and supplemental files like Makefiles or shell scripts in one of /ExternalProjects, /ExternalCoreProjects, or /waterbox when those are necessary. A minor problem with doing this...

> Improve overall emulation performance for modern (x86) CPUs (portability to other systems not guaranteed) Does this mean it wouldn't build for other CPU archs (e.g. ARM?). Also, how does...

> ARM used big endianness Not sure where you heard this, ARM is a little endian CPU (well, in practice it always is for any kind of ARM user)

> unfortunately MSVC's C++ compiler does not support it. Does clang-cl support it? Building under clang-cl/clang where possible would generally be preferred.

https://github.com/TASEmulators/BizHawk/blob/b5ebee7cd50c7a23649f2e97f964f897a997f2fa/LibretroBridge/LibretroBridge.cpp#L456 Failing at this assertion, needs more stuff added here, I guess: https://github.com/TASEmulators/BizHawk/blob/b5ebee7cd50c7a23649f2e97f964f897a997f2fa/LibretroBridge/LibretroBridge.h#L79-L85

https://github.com/libretro/RetroArch/blob/954b046/libretro-common/include/libretro.h#L207-L212 There's no other values valid for this... so I would just guess here that in fact this libretro core is just doing something very wrong here.