This fix a double break bug when hitting a memcheck and hitting play on the same instruction it broke to earlier. The state is put back to CPU_RUNNING after.
It wouldn't impact performance until at least one memcheck is enabled. Because of this, it can be used in release builds without much impact, the only thing that woudl change is the use of HasAny method instead of preprocessor conditionals. Since the perforamnce decrease comes right when the first memcheck is added and restored when the last is removed, it basically is all beneficial and works the same way.
Fix Frame Advance and FifoPlayer pause/unpause/stop.
CPU::EnableStepping is not atomic but is called from multiple threads
which races and leaves the system in a random state; also instruction
stepping was unstable, m_StepEvent had an almost random value because
of the dual purpose it served which could cause races where CPU::Run
would SingleStep when it was supposed to be sleeping.
FifoPlayer never FinishStateMove()d which was causing it to deadlock.
Rather than partially reimplementing CPU::Run, just use CPUCoreBase
and then call CPU::Run(). More DRY and less likely to have weird bugs
specific to the player (i.e the previous freezing on pause/stop).
Refactor PowerPC::state into CPU since it manages the state of the
CPU Thread which is controlled by CPU, not PowerPC. This simplifies
the architecture somewhat and eliminates races that can be caused by
calling PowerPC state functions directly instead of using CPU's
(because they bypassed the EnableStepping lock).
This addresses a bit of thread unsafety mentioned in a comment, and
fixes a 'ScheduleEvent_Threadsafe from main thread' message.
To make this work nicely, make PauseAndLock call DeclareAsCPUThread -
i.e. while you have the CPU thread locked, you can consider yourself the
CPU thread.
Change TMemCheck::Action to return whether to break rather than calling
PPCDebugInterface::BreakNow, as this simplified the implementation; then
remove said method, as that was its only caller. One "interface" method
down, many to go...
This is good for a couple of reasons: one, it gets rid of duplicated code,
and two, DSP emulation shouldn't need to interact with audio in the first
place.
