removed interrupt handling code

stella-emu · Jul 30, 2024 · 1a16d36 · 1a16d36
1 parent 5d1f4a2
commit 1a16d36
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Showing 2 changed files with 1 addition and 55 deletions.
diff --git a/src/emucore/M6502.cxx b/src/emucore/M6502.cxx
@@ -417,15 +417,6 @@ inline void M6502::_execute(uInt64 cycles, DispatchResult& result)
   #endif
     }
 
-    // JTZ, TODO: This code seems to be superfluous for a 6507:
-    // See if we need to handle an interrupt
-    if((myExecutionStatus & MaskableInterruptBit) ||
-        (myExecutionStatus & NonmaskableInterruptBit))
-    {
-      // Yes, so handle the interrupt
-      interruptHandler();
-    }
-
     // See if a fatal error has occurred
     if(myExecutionStatus & FatalErrorBit)
     {
@@ -450,34 +441,6 @@ inline void M6502::_execute(uInt64 cycles, DispatchResult& result)
   }
 }
 
-// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-void M6502::interruptHandler()
-{
-  // Handle the interrupt
-  if((myExecutionStatus & MaskableInterruptBit) && !I)
-  {
-    mySystem->incrementCycles(7 * SYSTEM_CYCLES_PER_CPU);
-    mySystem->poke(0x0100 + SP--, (PC - 1) >> 8);
-    mySystem->poke(0x0100 + SP--, (PC - 1) & 0x00ff);
-    mySystem->poke(0x0100 + SP--, PS() & (~0x10));
-    D = false;
-    I = true;
-    PC = static_cast<uInt16>(mySystem->peek(0xFFFE)) | (static_cast<uInt16>(mySystem->peek(0xFFFF)) << 8);
-  }
-  else if(myExecutionStatus & NonmaskableInterruptBit)
-  {
-    mySystem->incrementCycles(7 * SYSTEM_CYCLES_PER_CPU);
-    mySystem->poke(0x0100 + SP--, (PC - 1) >> 8);
-    mySystem->poke(0x0100 + SP--, (PC - 1) & 0x00ff);
-    mySystem->poke(0x0100 + SP--, PS() & (~0x10));
-    D = false;
-    PC = static_cast<uInt16>(mySystem->peek(0xFFFA)) | (static_cast<uInt16>(mySystem->peek(0xFFFB)) << 8);
-  }
-
-  // Clear the interrupt bits in myExecutionStatus
-  myExecutionStatus &= ~(MaskableInterruptBit | NonmaskableInterruptBit);
-}
-
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 bool M6502::save(Serializer& out) const
 {

diff --git a/src/emucore/M6502.hxx b/src/emucore/M6502.hxx
@@ -83,16 +83,6 @@ class M6502 : public Serializable
     */
     void reset();
 
-    /**
-      Request a maskable interrupt
-    */
-    void irq() { myExecutionStatus |= MaskableInterruptBit; }
-
-    /**
-      Request a non-maskable interrupt
-    */
-    void nmi() { myExecutionStatus |= NonmaskableInterruptBit; }
-
     /**
       Set the callback for handling a halt condition
     */
@@ -330,11 +320,6 @@ class M6502 : public Serializable
       C = ps & 0x01;
     }
 
-    /**
-      Called after an interrupt has be requested using irq() or nmi()
-    */
-    void interruptHandler();
-
     /**
       Check whether halt was requested (RDY low) and notify
     */
@@ -362,9 +347,7 @@ class M6502 : public Serializable
     */
     static constexpr uInt8
       StopExecutionBit        = 0x01,
-      FatalErrorBit           = 0x02,
-      MaskableInterruptBit    = 0x04,
-      NonmaskableInterruptBit = 0x08
+      FatalErrorBit           = 0x02
     ;
     uInt8 myExecutionStatus{0};