From 3ce546b774d27d32db733e6f86b9c4e3717bf927 Mon Sep 17 00:00:00 2001
From: alyosha-tas <alexei.f.k@gmail.com>
Date: Fri, 8 Jun 2018 12:28:51 -0400
Subject: [PATCH] z80: Resond to interrupts at the corect time

---
 .../CPUs/Z80A/Interrupts.cs                    |  4 ++--
 BizHawk.Emulation.Cores/CPUs/Z80A/Registers.cs |  2 +-
 BizHawk.Emulation.Cores/CPUs/Z80A/Z80A.cs      | 18 ++++++++++++------
 3 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/BizHawk.Emulation.Cores/CPUs/Z80A/Interrupts.cs b/BizHawk.Emulation.Cores/CPUs/Z80A/Interrupts.cs
index 9b1426505c..389fdf6e8f 100644
--- a/BizHawk.Emulation.Cores/CPUs/Z80A/Interrupts.cs
+++ b/BizHawk.Emulation.Cores/CPUs/Z80A/Interrupts.cs
@@ -85,7 +85,7 @@ namespace BizHawk.Emulation.Cores.Components.Z80A
 						OP_F,
 						OP };
 
-			BUSRQ = new ushort[] { 0, 0, 0, SPh, 0, 0, SPh, 0, 0, PCh, 0, 0, 0 };
+			BUSRQ = new ushort[] { I, 0, 0, SPh, 0, 0, SPh, 0, 0, PCh, 0, 0, 0 };
 		}
 
 		// Interrupt mode 2 uses the I vector combined with a byte on the data bus
@@ -112,7 +112,7 @@ namespace BizHawk.Emulation.Cores.Components.Z80A
 						OP_F,
 						OP };
 
-			BUSRQ = new ushort[] { 0, 0, 0, SPh, 0, 0, SPh, 0, 0, W, 0, 0, W, 0 ,0 ,PCh, 0, 0, 0 };
+			BUSRQ = new ushort[] { I, 0, 0, SPh, 0, 0, SPh, 0, 0, W, 0, 0, W, 0 ,0 ,PCh, 0, 0, 0 };
 		}
 
 		private static ushort[] INT_vectors = new ushort[] {0x40, 0x48, 0x50, 0x58, 0x60};
diff --git a/BizHawk.Emulation.Cores/CPUs/Z80A/Registers.cs b/BizHawk.Emulation.Cores/CPUs/Z80A/Registers.cs
index 7d4271373b..8ca466d5e2 100644
--- a/BizHawk.Emulation.Cores/CPUs/Z80A/Registers.cs
+++ b/BizHawk.Emulation.Cores/CPUs/Z80A/Registers.cs
@@ -58,7 +58,7 @@ namespace BizHawk.Emulation.Cores.Components.Z80A
 		public const ushort WIO4 = 108;
 
 
-		public bool FlagI;/*, FlagI1, FlagI2, FlagI3, FlagI4, FlagI5, FlagI6;*/
+		public bool FlagI, FlagI1, FlagI2, FlagI3, FlagI4, FlagI5, FlagI6;
 
 		public bool FlagW; // wait flag, when set to true reads / writes will be delayed
 
diff --git a/BizHawk.Emulation.Cores/CPUs/Z80A/Z80A.cs b/BizHawk.Emulation.Cores/CPUs/Z80A/Z80A.cs
index 33c60fc97f..afd07e1979 100644
--- a/BizHawk.Emulation.Cores/CPUs/Z80A/Z80A.cs
+++ b/BizHawk.Emulation.Cores/CPUs/Z80A/Z80A.cs
@@ -159,13 +159,13 @@ namespace BizHawk.Emulation.Cores.Components.Z80A
 		// Execute instructions
 		public void ExecuteOne()
 		{
-			/*FlagI6 = FlagI;
+			//FlagI6 = FlagI5;
 			FlagI5 = FlagI4;
 			FlagI4 = FlagI3;
 			FlagI3 = FlagI2;
 			FlagI2 = FlagI1;
 			FlagI1 = FlagI;
-			*/
+			
 			bus_pntr++;
 			switch (cur_instr[instr_pntr++])
 			{
@@ -196,7 +196,7 @@ namespace BizHawk.Emulation.Cores.Components.Z80A
 						NMICallback();
 						instr_pntr = 0; bus_pntr = 0;
 					}
-					else if (iff1 && FlagI)
+					else if (iff1 && FlagI5)
 					{
 						iff1 = iff2 = false;
 						EI_pending = 0;
@@ -267,7 +267,7 @@ namespace BizHawk.Emulation.Cores.Components.Z80A
 						NMICallback();
 						halted = false;
 					}
-					else if (iff1 && FlagI)
+					else if (iff1 && FlagI5)
 					{
 						iff1 = iff2 = false;
 						EI_pending = 0;
@@ -670,12 +670,12 @@ namespace BizHawk.Emulation.Cores.Components.Z80A
 									DEC16, PCl, PCh,
 									DEC16, PCl, PCh,
 									IDLE,
-									DEC16, B, ALU,
+									IDLE,//DEC16, B, ALU,
 									WAIT,
 									OP_F,
 									OP};
 
-						Regs[B] = (ushort)((Regs[B] + 1) & 0xFF);
+						//Regs[B] = (ushort)((Regs[B] + 1) & 0xFF);
 
 
 						BUSRQ = new ushort[] { B, B, B, B, B, PCh, 0, 0, 0 };
@@ -770,6 +770,12 @@ namespace BizHawk.Emulation.Cores.Components.Z80A
 			ser.Sync("instr_swap", ref instr_swap);
 			ser.Sync("opcode", ref opcode);
 			ser.Sync("FlagI", ref FlagI);
+			ser.Sync("FlagI1", ref FlagI1);
+			ser.Sync("FlagI2", ref FlagI2);
+			ser.Sync("FlagI3", ref FlagI3);
+			ser.Sync("FlagI4", ref FlagI4);
+			ser.Sync("FlagI5", ref FlagI5);
+			ser.Sync("FlagI6", ref FlagI6);
 			ser.Sync("FlagW", ref FlagW);
 
 			ser.Sync("NO Preifx", ref NO_prefix);