From 6ec1ce4d450b23fe9cb15863532ac19a92a9815a Mon Sep 17 00:00:00 2001
From: alyosha-tas <alexei.f.k@gmail.com>
Date: Mon, 13 Jan 2020 09:16:33 -0500
Subject: [PATCH] A2600: fix pitfall 2, needs a second look at some point
 though

---
 .../Consoles/Atari/2600/Tia/TIA.cs            | 32 +++++++++++++------
 .../Consoles/Atari/2600/Tia/Tia.SyncState.cs  |  6 ++++
 2 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/BizHawk.Emulation.Cores/Consoles/Atari/2600/Tia/TIA.cs b/BizHawk.Emulation.Cores/Consoles/Atari/2600/Tia/TIA.cs
index a7015e6760..9471f12de5 100644
--- a/BizHawk.Emulation.Cores/Consoles/Atari/2600/Tia/TIA.cs
+++ b/BizHawk.Emulation.Cores/Consoles/Atari/2600/Tia/TIA.cs
@@ -107,6 +107,12 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 		private int _hmbDelay;
 		private byte _hmbVal;
 
+		private bool _hmp0_no_tick;
+		private bool _hmp1_no_tick;
+		private bool _hmm0_no_tick;
+		private bool _hmm1_no_tick;
+		private bool _hmb_no_tick;
+
 		private int _nusiz0Delay;
 		private byte _nusiz0Val;
 		private int _nusiz1Delay;
@@ -732,7 +738,7 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 						_p0Stuff = false;
 
 						// "Clock-Stuffing"
-						if (_doTicks)
+						if (_doTicks && !_hmp0_no_tick)
 						{
 							_player0.Tick();
 						}
@@ -754,7 +760,7 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 						_p1Stuff = false;
 
 						// "Clock-Stuffing"
-						if (_doTicks)
+						if (_doTicks && !_hmp1_no_tick)
 						{
 							_player1.Tick();
 						}
@@ -776,7 +782,7 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 						_m0Stuff = false;
 
 						// "Clock-Stuffing"
-						if (_doTicks)
+						if (_doTicks && !_hmm0_no_tick)
 						{
 							_player0.Missile.Tick();
 						}
@@ -798,7 +804,7 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 						_m1Stuff = false;
 
 						// "Clock-Stuffing"
-						if (_doTicks)
+						if (_doTicks && !_hmm1_no_tick)
 						{
 							_player1.Missile.Tick();
 						}
@@ -820,7 +826,7 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 						_bStuff = false;
 
 						// "Clock-Stuffing"
-						if (_doTicks)
+						if (_doTicks && !_hmb_no_tick)
 						{
 							_ball.Tick();
 						}
@@ -896,6 +902,12 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 				_currentScanLine++;
 				LineCount++;
 			}
+
+			_hmp0_no_tick = false;
+			_hmp1_no_tick = false;
+			_hmm0_no_tick = false;
+			_hmm1_no_tick = false;
+			_hmb_no_tick = false;
 		}
 
 		private void OutputFrame(int validlines)
@@ -1346,7 +1358,7 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 			{
 				// RESP delays draw signal clocking
 				_player0.Resp_check();
-
+				//_hmp0_no_tick = true;
 				// Resp depends on HMOVE
 				if (!_hmove.LateHBlankReset)
 				{
@@ -1369,7 +1381,7 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 			{
 				// RESP delays draw signal clocking
 				_player1.Resp_check();
-
+				//_hmp1_no_tick = true;
 				// RESP depends on HMOVE
 				if (!_hmove.LateHBlankReset)
 				{
@@ -1393,7 +1405,7 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 				// RESP delays draw signal clocking
 				// but only for players? Needs investigation
 				//_player0.Missile.Resp_check();
-
+				_hmm0_no_tick = true;
 				if (!_hmove.LateHBlankReset)
 				{
 					_player0.Missile.HPosCnt = (byte)(_hsyncCnt < 68 ? 160 - 2 : 160 - 4);
@@ -1416,7 +1428,7 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 				// RESP delays draw signal clocking
 				// but only for players? Needs investigation
 				//_player1.Missile.Resp_check();
-
+				_hmm1_no_tick = true;
 				if (!_hmove.LateHBlankReset)
 				{
 					_player1.Missile.HPosCnt = (byte)(_hsyncCnt < 68 ? 160 - 2 : 160 - 4);
@@ -1439,7 +1451,7 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 				// RESP delays draw signal clocking
 				// but only for players? Needs investigation
 				//_ball.Resp_check();
-
+				_hmb_no_tick = true;
 				if (!_hmove.LateHBlankReset)
 				{
 					_ball.HPosCnt = (byte)(_hsyncCnt < 68 ? 160 - 2 : 160 - 4);
diff --git a/BizHawk.Emulation.Cores/Consoles/Atari/2600/Tia/Tia.SyncState.cs b/BizHawk.Emulation.Cores/Consoles/Atari/2600/Tia/Tia.SyncState.cs
index 9c8c4ca6aa..518236eee3 100644
--- a/BizHawk.Emulation.Cores/Consoles/Atari/2600/Tia/Tia.SyncState.cs
+++ b/BizHawk.Emulation.Cores/Consoles/Atari/2600/Tia/Tia.SyncState.cs
@@ -41,6 +41,12 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
 			ser.Sync("M0_stuff", ref _m0Stuff);
 			ser.Sync("M1_stuf", ref _m1Stuff);
 			ser.Sync("b_stuff", ref _bStuff);
+			
+			ser.Sync("_hmp0_no_tick", ref _hmp0_no_tick);
+			ser.Sync("_hmp1_no_tick", ref _hmp1_no_tick);
+			ser.Sync("_hmm0_no_tick", ref _hmm0_no_tick);
+			ser.Sync("_hmm1_no_tick", ref _hmm1_no_tick);
+			ser.Sync("_hmb_no_tick", ref _hmb_no_tick);
 
 			ser.Sync("hmp0_delay", ref _hmp0Delay);
 			ser.Sync("hmp0_val", ref _hmp0Val);