From 02cd2f47f30997b895426fa8b89fd8d59ff0df1e Mon Sep 17 00:00:00 2001
From: alyosha-tas <alexei.f.k@gmail.com>
Date: Fri, 18 Jun 2021 23:08:04 -0400
Subject: [PATCH] NESHawk: update lag definition and add sprite address glitch

---
 .../Consoles/Nintendo/NES/NES.Core.cs         |  6 +++++-
 .../Consoles/Nintendo/NES/PPU.cs              |  4 +++-
 .../Consoles/Nintendo/NES/PPU.regs.cs         |  6 +++---
 .../Consoles/Nintendo/NES/PPU.run.cs          | 19 ++++++++++++++++---
 4 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/NES.Core.cs b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/NES.Core.cs
index 24a2988f1f..73fee421c1 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/NES.Core.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/NES.Core.cs
@@ -744,6 +744,8 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 
 		private void write_joyport(byte value)
 		{
+			//Console.WriteLine("cont " + value + " frame " + Frame);
+			
 			var si = new StrobeInfo(latched4016, value);
 			ControllerDeck.Strobe(si, _controller);
 			latched4016 = value;
@@ -752,13 +754,15 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 			{
 				controller_was_latched = true;
 				alt_lag = false;
+				lagged = false;
 			}
+			current_strobe = new_strobe;
 		}
 
 		private byte read_joyport(int addr)
 		{
 			InputCallbacks.Call();
-			lagged = false;
+
 			byte ret;
 			if (_isVS)
 			{
diff --git a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/PPU.cs b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/PPU.cs
index ef96f42cd3..d4cd8c6d9f 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/PPU.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/PPU.cs
@@ -3,7 +3,7 @@ using BizHawk.Common;
 
 namespace BizHawk.Emulation.Cores.Nintendo.NES
 {
-	public sealed partial class PPU
+	public partial class PPU
 	{
 		public int cpu_step, cpu_stepcounter;
 
@@ -260,6 +260,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 			ser.Sync(nameof(yp), ref yp);
 			ser.Sync(nameof(target), ref target);
 			ser.Sync(nameof(ppu_was_on), ref ppu_was_on);
+			ser.Sync(nameof(ppu_was_on_spr), ref ppu_was_on_spr);
 			ser.Sync(nameof(spriteHeight), ref spriteHeight);
 			ser.Sync(nameof(install_2006), ref install_2006);
 			ser.Sync(nameof(race_2006), ref race_2006);
@@ -356,6 +357,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 			ppu_open_bus = 0;
 			ppu_open_bus_decay_timer = new int[8];
 			double_2007_read = 0;
+			start_up_offset = 2;
 		}
 
 		private void runppu()
diff --git a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/PPU.regs.cs b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/PPU.regs.cs
index 67b1d02ef2..ea5102cb26 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/PPU.regs.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/PPU.regs.cs
@@ -12,7 +12,7 @@ using BizHawk.Common;
 
 namespace BizHawk.Emulation.Cores.Nintendo.NES
 {
-	sealed partial class PPU
+	public partial class PPU
 	{
 		public sealed class Reg_2001
 		{
@@ -294,7 +294,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 		public PPUREGS ppur;
 		public Reg_2000 reg_2000;
 		public Reg_2001 reg_2001;
-		private byte reg_2003;
+		public byte reg_2003;
 		public byte reg_2006_2;
 
 		private void regs_reset()
@@ -436,7 +436,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 				{
 					OAM[reg_2003] = value;
 					reg_2003++;
-				}
+				}				
 			}
 			else
 			{
diff --git a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/PPU.run.cs b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/PPU.run.cs
index decb671de3..606f014f6c 100644
--- a/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/PPU.run.cs
+++ b/src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/PPU.run.cs
@@ -2,11 +2,12 @@
 
 using BizHawk.Common;
 using BizHawk.Common.NumberExtensions;
+using System;
 using System.Runtime.CompilerServices;
 
 namespace BizHawk.Emulation.Cores.Nintendo.NES
 {
-	sealed partial class PPU
+	public partial class PPU
 	{
 		private struct BGDataRecord
 		{
@@ -36,6 +37,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 		public int spriteHeight;
 		public byte[] soam = new byte[256]; // in a real nes, this would only be 32, but we wish to allow more then 8 sprites per scanline
 		public bool ppu_was_on;
+		public bool ppu_was_on_spr;
 		public byte[] sl_sprites = new byte[3 * 256];
 
 		// installing vram address is delayed after second write to 2006, set this up here
@@ -131,7 +133,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 
 		private bool nmi_destiny;
 		private bool evenOddDestiny;
-		private static readonly int start_up_offset = 2;
+		private int start_up_offset;
 		private int NMI_offset;
 		private int yp_shift;
 		private int sprite_eval_cycle;
@@ -524,7 +526,18 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 
 						//check all the conditions that can cause things to render in these 8px
 						renderspritenow = show_obj_new && (xt > 0 || reg_2001.show_obj_leftmost);
-					}				
+					}	
+					
+					if (ppur.status.cycle > 63)
+					{
+						if (ppu_was_on_spr && !PPUON)
+						{
+							Console.WriteLine("oam addr glitch " + ppur.status.sl + " " + ppur.status.cycle);
+							reg_2003++;
+						}
+					}
+					
+					ppu_was_on_spr = PPUON;
 				}
 				else
 				{