Instead of having the configuration being loaded and stored in to a
frontend system. First moves the backing store of the configuration in
to FEXCore.
Each layer that is constructed then loads its particular configuration.
After the layers are loaded, then a meta layer is constructed that
merges the layers flat.
This means we will no longer hit the problem where a configuration is
stored in the "main" configuration file, then environment and arguments
passed manage to overwrite it.
The order of the layers going from inner most layer to outer most, with
outermost overwriting previous layer configurations is as follows:
Main < Global application < Local application < Arguments < Environment
One step that needs to be changed in the future is that FEXCore can then
just load its configuration from the layers directly since the data is
in FEXCore now. This will be reserved for a future change so we are less
disruptive.
This implements support for 130 of the 132 x87 ops as interpreter
fallbacks.
The two missing ops are the BCD load and BCD store instructions and can
be implemented another time.
This allows us to no longer have to rely on a libstdc++ modification to
handle their usage of long double. This instead works entirely through
using `long double` directly in the interpreter. Which will either use
real x87 on an x86 host. Or in the case of ARM devices, fall down
glibc's long double soft float path.
This doesn't necessarily need to be quick right now. It's more important
to have the compatibility improvement from this.
Stefanos Kornilios Mitsis Poiitidis