Previously, PowerPC.h had four macros in it like so:
\#define rPS0(i) (*(double*)(&PowerPC::ppcState.ps[i][0]))
\#define rPS1(i) (*(double*)(&PowerPC::ppcState.ps[i][1]))
\#define riPS0(i) (*(u64*)(&PowerPC::ppcState.ps[i][0]))
\#define riPS1(i) (*(u64*)(&PowerPC::ppcState.ps[i][1]))
Casting between object representations like this is undefined behavior.
Given this is used heavily with the interpreter (that is, the most
accurate, but slowest CPU backend), we don't exactly want to allow
undefined behavior to creep into it.
Instead, this adds a helper struct for operating with the paired singles,
and replaces the four macros with a single macro for accessing the
paired-singles/floating-point registers.
This way, it's left up to the caller to explicitly decide how it wants to interpret
the data (and makes it more obvious where different interpretations of
the same data are occurring at, as there'll be a call to one of the
[x]AsDouble() functions).
These bits enable or disable paired-single execution based on how
they're set. If PSE isn't set, then all paired-single instructions are
illegal. If PSE is set, but LSQE isn't set, then psq_l, psq_lu, psq_st
and psq_stu are illegal to execute.
Also thanks go out to my roommate @Veegie for letting me use his Wii as
a blasting ground for tests, since mine isn't on hand right now. It only
caught on fire twice and only burned down half of the house through the
process; what a team player.
Since we use the common pipelines here and draw vertices if a batch is
currently being built by the vertex loader, we end up trampling over its
pointer, as we share the buffer with the loader, and it has not been
unmapped yet. Force a pipeline flush to avoid this.
This could happen with savestate loads, permission issues, or use by other processes.
Prior to this Dolphin assumed any existing file could be opened and crashes from invalid variant access.
Failing to open a file during savestate load will likely still crash but at least the user will know why.
