DSP JIT: Fix infinite loop if an exception is suppressed

I'm not 100% sure about the LoadRegs(false) part.

Source/Core/Core/DSP/DSPCore.cpp

@@ -213,11 +213,11 @@ void SDSP::CheckExternalInterrupt()
   control_reg &= ~CR_EXTERNAL_INT;
 }
 
-void SDSP::CheckExceptions()
+bool SDSP::CheckExceptions()
 {
   // Early out to skip the loop in the common case.
   if (exceptions == 0)
-    return;
+    return false;
 
   for (int i = 7; i > 0; i--)
   {
@@ -236,7 +236,7 @@ void SDSP::CheckExceptions()
           r.sr &= ~SR_EXT_INT_ENABLE;
         else
           r.sr &= ~SR_INT_ENABLE;
-        break;
+        return true;
       }
       else
       {
@@ -246,6 +246,8 @@ void SDSP::CheckExceptions()
       }
     }
   }
+
+  return false;
 }
 
 u16 SDSP::ReadRegister(size_t reg) const
@@ -530,9 +532,9 @@ void DSPCore::CheckExternalInterrupt()
   m_dsp.CheckExternalInterrupt();
 }
 
-void DSPCore::CheckExceptions()
+bool DSPCore::CheckExceptions()
 {
-  m_dsp.CheckExceptions();
+  return m_dsp.CheckExceptions();
 }
 
 u16 DSPCore::ReadRegister(size_t reg) const

Source/Core/Core/DSP/DSPCore.h

@@ -382,8 +382,9 @@ struct SDSP
   // and sets a flag in the pending exception register.
   void SetException(ExceptionType exception);
 
-  // Checks if any exceptions occurred an updates the DSP state as appropriate.
+  // Checks if any exceptions occurred and updates the DSP state as appropriate.
-  void CheckExceptions();
+  // Returns true if PC changed.
+  bool CheckExceptions();
 
   // Notify that an external interrupt is pending (used by thread mode)
   void SetExternalInterrupt(bool val);
@@ -529,8 +530,9 @@ public:
   // Coming from the CPU
   void CheckExternalInterrupt();
 
-  // Checks if any exceptions occurred an updates the DSP state as appropriate.
+  // Checks if any exceptions occurred and updates the DSP state as appropriate.
-  void CheckExceptions();
+  // Returns true if PC changed.
+  bool CheckExceptions();
 
   // Reads the current value from a particular register.
   u16 ReadRegister(size_t reg) const;

Source/Core/Core/DSP/Jit/x64/DSPEmitter.cpp

@@ -99,13 +99,13 @@ void DSPEmitter::ClearIRAMandDSPJITCodespaceReset()
   m_dsp_core.DSPState().reset_dspjit_codespace = false;
 }
 
-static void CheckExceptionsThunk(DSPCore& dsp)
+static bool CheckExceptionsThunk(DSPCore& dsp)
 {
-  dsp.CheckExceptions();
+  return dsp.CheckExceptions();
 }
 
 // Must go out of block if exception is detected
-void DSPEmitter::checkExceptions(u32 retval)
+void DSPEmitter::checkExceptions(u16 retval)
 {
   // Check for interrupts and exceptions
   TEST(8, M_SDSP_exceptions(), Imm8(0xff));
@@ -116,9 +116,10 @@ void DSPEmitter::checkExceptions(u32 retval)
   DSPJitRegCache c(m_gpr);
   m_gpr.SaveRegs();
   ABI_CallFunctionP(CheckExceptionsThunk, &m_dsp_core);
-  MOV(32, R(EAX), Imm32(retval));
+  TEST(8, R(ABI_RETURN), R(ABI_RETURN));
-  JMP(m_return_dispatcher, Jump::Near);
+  MOV(16, R(EAX), Imm16(retval));
-  m_gpr.LoadRegs(false);
+  J_CC(CC_NZ, m_return_dispatcher);
+  m_gpr.LoadRegs(false);  // TODO: Does this still make sense?
   m_gpr.FlushRegs(c, false);
 
   SetJumpTarget(skipCheck);

Source/Core/Core/DSP/Jit/x64/DSPEmitter.h

@@ -263,7 +263,7 @@ private:
   // Register helpers
   void setCompileSR(u16 bit);
   void clrCompileSR(u16 bit);
-  void checkExceptions(u32 retval);
+  void checkExceptions(u16 retval);
 
   // Memory helper functions
   void increment_addr_reg(int reg);