-Noted interrupts in the log.

-Added and Interrupted flag to make it so that interrupts only trigger once per falling edge.
-For now, interrupts take 28 cycles.
-Made it so that the STIC tracks Pending / Total Executed Cycles just like the CPU.
-Forwarded the cycles executed in the CPU to the STIC's Execute.
-SR1 is now inverted when there are no pending cycles.
--If SR1 is high, 14394 cycles are added to the pending cycles.
--If SR1 is low, 3791 cycles are added to the pending cycles.

BizHawk.Emulation/CPUs/CP1610/CP1610.cs

@@ -8,7 +8,7 @@ namespace BizHawk.Emulation.CPUs.CP1610
 		private const ushort RESET = 0x1000;
 		private const ushort INTERRUPT = 0x1004;
 
-		private bool FlagS, FlagC, FlagZ, FlagO, FlagI, FlagD, IntRM, BusRq, BusAk, MSync, Interruptible;
+		private bool FlagS, FlagC, FlagZ, FlagO, FlagI, FlagD, IntRM, BusRq, BusAk, MSync, Interruptible, Interrupted;
 		private ushort[] Register = new ushort[8];
 		private ushort RegisterSP { get { return Register[6]; } set { Register[6] = value; } }
 		private ushort RegisterPC { get { return Register[7]; } set { Register[7] = value; } }
@@ -48,16 +48,16 @@ namespace BizHawk.Emulation.CPUs.CP1610
 			IntRM = value;
 		}
 
-		public int GetPendingCycles()
-		{
-			return PendingCycles;
-		}
-
 		public void SetBusRq(bool value)
 		{
 			BusRq = value;
 		}
 
+		public int GetPendingCycles()
+		{
+			return PendingCycles;
+		}
+
 		public void AddPendingCycles(int cycles)
 		{
 			PendingCycles += cycles;

BizHawk.Emulation/CPUs/CP1610/Execute.cs

@@ -90,8 +90,26 @@ namespace BizHawk.Emulation.CPUs.CP1610
 				Register[mem]++;
 		}
 
-		public void Execute()
+		public int Execute()
 		{
+			/*
+			 Take an interrupt if the previous instruction was interruptible,
+			 interrupts are enabled, and IntRM has a falling edge.
+			*/
+			if (FlagI && Interruptible && !IntRM && !Interrupted)
+			{
+				if (logging)
+				{
+					log.WriteLine("------");
+					log.WriteLine();
+					log.WriteLine("Interrupt");
+				}
+				Interrupted = true;
+				Interruptible = false;
+				Indirect_Set(6, 7);
+				RegisterPC = INTERRUPT;
+				return 28;
+			}
 			if (logging)
 			{
 				int addrToAdvance;
@@ -100,16 +118,11 @@ namespace BizHawk.Emulation.CPUs.CP1610
 				log.WriteLine(Disassemble(RegisterPC, out addrToAdvance));
 				log.Flush();
 			}
-			if (FlagI && Interruptible && !IntRM)
-			{
-				Indirect_Set(6, 7);
-				RegisterPC = INTERRUPT;
-			}
 			byte dest, src, mem;
 			ushort dest_value, src_value, mem_read, addr, addr_read, offset;
 			int cycles = 0, decle2, decle3, result = 0, ones, carry, status_word, lower, sign, cond, ext;
 			bool branch = false;
-			bool prev_FlagD = FlagD;
+			bool FlagD_prev = FlagD;
 			int opcode = ReadMemory(RegisterPC++) & 0x3FF;
 			switch (opcode)
 			{
@@ -1778,9 +1791,11 @@ namespace BizHawk.Emulation.CPUs.CP1610
 					Interruptible = true;
 					break;
 			}
-			if (FlagD == prev_FlagD)
+			if (FlagD == FlagD_prev)
 				FlagD = false;
-			PendingCycles -= cycles; TotalExecutedCycles += cycles;
+			PendingCycles -= cycles;
+			TotalExecutedCycles += cycles;
+			return cycles;
 		}
 	}
 }

BizHawk.Emulation/Consoles/Intellivision/Intellivision.cs

@@ -78,11 +78,11 @@ namespace BizHawk.Emulation.Consoles.Intellivision
 
 		public void FrameAdvance(bool render)
 		{
-			Cpu.AddPendingCycles(999);
+			Cpu.AddPendingCycles(14394 + 3791);
 			while (Cpu.GetPendingCycles() > 0)
 			{
-				Cpu.Execute();
+				int cycles = Cpu.Execute();
-				Stic.Execute();
+				Stic.Execute(cycles);
 				Connect();
 				Cpu.LogData();
 			}

BizHawk.Emulation/Consoles/Intellivision/STIC.cs

@@ -9,6 +9,9 @@ namespace BizHawk.Emulation.Consoles.Intellivision
 	{
 		private bool Sr1, Sr2, Sst, Fgbg = false;
 		private ushort[] Register = new ushort[64];
+
+		public int TotalExecutedCycles;
+		public int PendingCycles;
 		
 		public void Reset()
 		{
@@ -31,6 +34,16 @@ namespace BizHawk.Emulation.Consoles.Intellivision
 			Sst = value;
 		}
 
+		public int GetPendingCycles()
+		{
+			return PendingCycles;
+		}
+
+		public void AddPendingCycles(int cycles)
+		{
+			PendingCycles += cycles;
+		}
+
 		public ushort? ReadSTIC(ushort addr)
 		{
 			switch (addr & 0xF000)
@@ -126,9 +139,18 @@ namespace BizHawk.Emulation.Consoles.Intellivision
 			return false;
 		}
 
-		public void Execute()
+		public void Execute(int cycles)
 		{
-			Sr1 = false;
+			if (PendingCycles <= 0)
+			{
+				Sr1 = !Sr1;
+				if (Sr1)
+					AddPendingCycles(14394);
+				else
+					AddPendingCycles(3791);
+			}
+			PendingCycles -= cycles;
+			TotalExecutedCycles += cycles;
 		}
 	}
 }