PowerPC: Set host CPU rounding mode on init and savestate

Not doing this can cause desyncs when TASing. (I don't know
how common such desyncs would be, though. For games that
don't change rounding modes, they shouldn't be a problem.)

Source/Core/Core/PowerPC/PowerPC.cpp

@@ -20,6 +20,7 @@
 #include "Common/Logging/Log.h"
 
 #include "Core/ConfigManager.h"
+#include "Core/Core.h"
 #include "Core/CoreTiming.h"
 #include "Core/HW/CPU.h"
 #include "Core/HW/SystemTimers.h"
@@ -129,6 +130,7 @@ void DoState(PointerWrap& p)
 
   if (p.GetMode() == PointerWrap::MODE_READ)
   {
+    RoundingModeUpdated();
     IBATUpdated();
     DBATUpdated();
   }
@@ -180,6 +182,7 @@ static void ResetRegisters()
   }
   SetXER({});
 
+  RoundingModeUpdated();
   DBATUpdated();
   IBATUpdated();
 
@@ -246,10 +249,6 @@ CPUCore DefaultCPUCore()
 
 void Init(CPUCore cpu_core)
 {
-  // NOTE: This function runs on EmuThread, not the CPU Thread.
-  //   Changing the rounding mode has a limited effect.
-  FPURoundMode::SetPrecisionMode(FPURoundMode::PREC_53);
-
   s_invalidate_cache_thread_safe =
       CoreTiming::RegisterEvent("invalidateEmulatedCache", InvalidateCacheThreadSafe);
 
@@ -632,4 +631,13 @@ void UpdateFPRF(double dvalue)
   FPSCR.FPRF = Common::ClassifyDouble(dvalue);
 }
 
+void RoundingModeUpdated()
+{
+  // The rounding mode is separate for each thread, so this must run on the CPU thread
+  ASSERT(Core::IsCPUThread());
+
+  FPURoundMode::SetRoundMode(FPSCR.RN);
+  FPURoundMode::SetSIMDMode(FPSCR.RN, FPSCR.NI);
+}
+
 }  // namespace PowerPC