From e14a32dd8c744f3f01b512c22cfe4c50abd1d3a0 Mon Sep 17 00:00:00 2001
From: Brandon Wright <bearoso@gmail.com>
Date: Thu, 17 May 2018 14:41:48 -0500
Subject: [PATCH] Add some NMI debugging info.

---
 cpuexec.cpp | 15 +++++++++++++++
 debug.cpp   |  5 +++--
 ppu.cpp     | 11 +++++++++++
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/cpuexec.cpp b/cpuexec.cpp
index f5fc203a..336560f7 100644
--- a/cpuexec.cpp
+++ b/cpuexec.cpp
@@ -211,6 +211,10 @@ void S9xMainLoop (void)
 	{
 		if (CPU.NMIPending)
 		{
+			#ifdef DEBUGGER
+			if (Settings.TraceHCEvent)
+			    S9xTraceFormattedMessage ("Comparing %d to %d\n", Timings.NMITriggerPos, CPU.Cycles);
+			#endif
 			if (Timings.NMITriggerPos <= CPU.Cycles)
 			{
 				CPU.NMIPending = FALSE;
@@ -414,7 +418,14 @@ void S9xDoHEventProcessing (void)
 			S9xAPUSetReferenceTime(CPU.Cycles);
 
 			if ((Timings.NMITriggerPos != 0xffff) && (Timings.NMITriggerPos >= Timings.H_Max))
+			{
 				Timings.NMITriggerPos -= Timings.H_Max;
+#ifdef DEBUGGER
+				if (Settings.TraceHCEvent)
+				    S9xTraceFormattedMessage ("NMI Trigger pos changed to %d\n", Timings.NMITriggerPos);
+#endif
+			}
+
 
 			CPU.V_Counter++;
 			if (CPU.V_Counter >= Timings.V_Max)	// V ranges from 0 to Timings.V_Max - 1
@@ -503,6 +514,10 @@ void S9xDoHEventProcessing (void)
 				Memory.FillRAM[0x4210] = 0x80 | Model->_5A22;
 				if (Memory.FillRAM[0x4200] & 0x80)
 				{
+#ifdef DEBUGGER
+					if (Settings.TraceHCEvent)
+					    S9xTraceFormattedMessage ("NMI Scheduled for next scanline.");
+#endif
 					// FIXME: triggered at HC=6, checked just before the final CPU cycle,
 					// then, when to call S9xOpcode_NMI()?
 					CPU.NMIPending = TRUE;
diff --git a/debug.cpp b/debug.cpp
index aa023c8a..46dfb13c 100644
--- a/debug.cpp
+++ b/debug.cpp
@@ -889,7 +889,7 @@ static uint8 debug_cpu_op_print (char *Line, uint8 Bank, uint16 Address)
 			break;
 	}
 
-	sprintf(Line, "%-44s A:%04X X:%04X Y:%04X D:%04X DB:%02X S:%04X P:%c%c%c%c%c%c%c%c%c HC:%04ld VC:%03ld FC:%02d %03x",
+	sprintf(Line, "%-44s A:%04X X:%04X Y:%04X D:%04X DB:%02X S:%04X P:%c%c%c%c%c%c%c%c%c HC:%04ld VC:%03ld FC:%02d %03x %c",
 	        Line, Registers.A.W, Registers.X.W, Registers.Y.W,
 	        Registers.D.W, Registers.DB, Registers.S.W,
 	        CheckEmulation() ? 'E' : 'e',
@@ -904,7 +904,8 @@ static uint8 debug_cpu_op_print (char *Line, uint8 Bank, uint16 Address)
 	        (long) CPU.Cycles,
 	        (long) CPU.V_Counter,
 	        IPPU.FrameCount,
-	        (CPU.IRQExternal ? 0x100 : 0) | (PPU.HTimerEnabled ? 0x10 : 0) | (PPU.VTimerEnabled ? 0x01 : 0));
+	        (CPU.IRQExternal ? 0x100 : 0) | (PPU.HTimerEnabled ? 0x10 : 0) | (PPU.VTimerEnabled ? 0x01 : 0),
+	        CPU.NMIPending ? 'N' : '.');
 
 	return (Size);
 }
diff --git a/ppu.cpp b/ppu.cpp
index d1e2bafa..a2a0c0b3 100644
--- a/ppu.cpp
+++ b/ppu.cpp
@@ -1476,6 +1476,10 @@ void S9xSetCPU (uint8 Byte, uint16 Address)
 		switch (Address)
 		{
 			case 0x4200: // NMITIMEN
+				#ifdef DEBUGGER
+				if (Settings.TraceHCEvent)
+				    S9xTraceFormattedMessage("Write to 0x4200. Byte is %2x was %2x\n", Byte, Memory.FillRAM[Address]);
+				#endif
 				if (Byte & 0x20)
 				{
 					PPU.VTimerEnabled = TRUE;
@@ -1511,10 +1515,17 @@ void S9xSetCPU (uint8 Byte, uint16 Address)
 				if ((Byte & 0x80) && !(Memory.FillRAM[0x4200] & 0x80) &&
 					(CPU.V_Counter >= PPU.ScreenHeight + FIRST_VISIBLE_LINE) && (Memory.FillRAM[0x4210] & 0x80))
 				{
+
 					// FIXME: triggered at HC+=6, checked just before the final CPU cycle,
 					// then, when to call S9xOpcode_NMI()?
 					CPU.NMIPending = TRUE;
 					Timings.NMITriggerPos = CPU.Cycles + 6 + 6;
+
+#ifdef DEBUGGER
+if (Settings.TraceHCEvent)
+    S9xTraceFormattedMessage("NMI Triggered on low-to-high occurring at next HC=%d\n", Timings.NMITriggerPos);
+#endif
+
 				}
 
                 #ifdef DEBUGGER