From 78bc52cd8ed1c31560a38b74e64a8dd63140c6cb Mon Sep 17 00:00:00 2001
From: Brandon Wright <bearoso@gmail.com>
Date: Mon, 28 May 2018 18:24:11 -0500
Subject: [PATCH] Add some debugging info. Don't reset timer when reading
 $4211.

---
 cpuexec.cpp   |  3 +++
 debug.cpp     |  7 ++++---
 ppu.cpp       | 15 +++++++++------
 unix/unix.cpp | 19 +++++++++++++++++++
 unix/x11.cpp  |  1 +
 5 files changed, 36 insertions(+), 9 deletions(-)

diff --git a/cpuexec.cpp b/cpuexec.cpp
index 631f6a51..e3cf5a1a 100644
--- a/cpuexec.cpp
+++ b/cpuexec.cpp
@@ -257,6 +257,9 @@ void S9xMainLoop (void)
 				CPU.IRQPending--;
 			else
 			{
+				#ifdef DEBUGGER
+				S9xTraceMessage ("Timer triggered\n");
+				#endif
 				CPU.IRQTransition = TRUE;
 			}
 		}
diff --git a/debug.cpp b/debug.cpp
index 2825cdbf..972c873e 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 %c %c%c",
+	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 %c%c%c %c %c%c HT:%d VT:%d C:%d",
 	        Line, Registers.A.W, Registers.X.W, Registers.Y.W,
 	        Registers.D.W, Registers.DB, Registers.S.W,
 	        CheckEmulation() ? 'E' : 'e',
@@ -904,10 +904,11 @@ 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 ?  'E' : ' ', PPU.HTimerEnabled ? 'H' : ' ', PPU.VTimerEnabled ? 'V' : ' ',
 	        CPU.NMIPending ? 'N' : '.',
 	        CPU.IRQTransition ? 'T' : ' ',
-	        CPU.IRQLine ? 'L' : ' ');
+	        CPU.IRQLine ? 'L' : ' ',
+	        PPU.HTimerPosition, PPU.VTimerPosition, Timings.NextIRQTimer);
 
 	return (Size);
 }
diff --git a/ppu.cpp b/ppu.cpp
index ccf610a7..c2cf76d0 100644
--- a/ppu.cpp
+++ b/ppu.cpp
@@ -333,7 +333,7 @@ void S9xUpdateIRQPositions (bool initial)
 	else if (PPU.HTimerEnabled && !PPU.VTimerEnabled)
 	{
 		Timings.NextIRQTimer = PPU.HTimerPosition;
-		if (CPU.Cycles > Timings.NextIRQTimer)
+		if (CPU.Cycles > Timings.NextIRQTimer - Timings.IRQTriggerCycles)
 			Timings.NextIRQTimer += Timings.H_Max;
 	}
 	else if (!PPU.HTimerEnabled && PPU.VTimerEnabled)
@@ -349,7 +349,7 @@ void S9xUpdateIRQPositions (bool initial)
 	}
 
 #ifdef DEBUGGER
-	S9xTraceFormattedMessage("--- IRQ Timer set %d cycles HTimer:%d Pos:%04d->%04d  VTimer:%d Pos:%03d->%03d",
+	S9xTraceFormattedMessage("--- IRQ Timer HC:%d VC:%d %s %d cycles HTimer:%d Pos:%04d->%04d  VTimer:%d Pos:%03d->%03d", CPU.Cycles, CPU.V_Counter, initial ? "set" : "recur",
 		Timings.NextIRQTimer, PPU.HTimerEnabled, PPU.IRQHBeamPos, PPU.HTimerPosition, PPU.VTimerEnabled, PPU.IRQVBeamPos, PPU.VTimerPosition);
 #endif
 }
@@ -1848,10 +1848,13 @@ uint8 S9xGetCPU (uint16 Address)
 				return ((byte & 0x80) | (OpenBus & 0x70) | Model->_5A22);
 
 			case 0x4211: // TIMEUP
-				byte = CPU.IRQLine ? 0x80 : 0;
-				CPU.IRQLine = FALSE;
-				CPU.IRQTransition = FALSE;
-				S9xUpdateIRQPositions(false);
+				byte = 0;
+				if (CPU.IRQLine)
+				{
+					byte = 0x80;
+					CPU.IRQLine = FALSE;
+					CPU.IRQTransition = FALSE;
+				}
 
 				return (byte | (OpenBus & 0x7f));
 
diff --git a/unix/unix.cpp b/unix/unix.cpp
index 8b8ee430..5ac14cb4 100644
--- a/unix/unix.cpp
+++ b/unix/unix.cpp
@@ -306,6 +306,8 @@ struct SoundStatus
 	int32	play_position;
 };
 
+
+static int frame_advance = 0;
 static SUnixSettings	unixSettings;
 static SoundStatus		so;
 
@@ -1188,6 +1190,12 @@ s9xcommand_t S9xGetPortCommandT (const char *n)
 
 		return (cmd);
 	}
+        else if (!strcmp(n, "Advance"))
+        {
+                cmd.type = S9xButtonPort;
+                cmd.port[1] = 3;
+                return (cmd);
+        }
 
 	return (S9xGetDisplayCommandT(n));
 }
@@ -1220,6 +1228,9 @@ char * S9xGetPortCommandName (s9xcommand_t cmd)
 
 				case 2:
 					return (strdup("Rewind"));
+
+                                case 3:
+                                        return (strdup("Advance"));
 			}
 
 			break;
@@ -1260,6 +1271,9 @@ void S9xHandlePortCommand (s9xcommand_t cmd, int16 data1, int16 data2)
 				case 2:
 					rewinding = (bool8) data1;
 					break;
+
+                                case 3:
+                                        frame_advance = (bool8) data1;
 			}
 
 			break;
@@ -1945,6 +1959,11 @@ int main (int argc, char **argv)
 
 			S9xMainLoop();
 		}
+                if (Settings.Paused && frame_advance)
+                {
+                        S9xMainLoop();
+                        frame_advance = 0;
+                }
 
 	#ifdef NETPLAY_SUPPORT
 		if (NP_Activated)
diff --git a/unix/x11.cpp b/unix/x11.cpp
index 0e51ddc8..cf4d8d03 100644
--- a/unix/x11.cpp
+++ b/unix/x11.cpp
@@ -567,6 +567,7 @@ const char * S9xParseDisplayConfig (ConfigFile &conf, int pass)
 		keymaps.push_back(strpair_t("K00:slash",        "Superscope Pause"));
 
 		keymaps.push_back(strpair_t("K00:r",            "Rewind"));
+                keymaps.push_back(strpair_t("K00:l",            "Advance"));
 	}
 
 	GUI.no_repeat = !conf.GetBool("Unix/X11::SetKeyRepeat", TRUE);