* Added some comments on System.

* New routine PadOneKeySinglePress() and PadTwoKeySinglePress().
* Temp waypoints now turn red when colliding with an aircraft or with a previously existing waypoint.
* When loading files, GPU operation is finishedbefore calling fopen. Also, I_MASK is disabled just in case.
* For PLT files, actual tile needs to be set instead of parking number.

14 files changed, 485 insertions, 135 deletions

diff --git a/Source/Aircraft.c b/Source/Aircraft.c
index aed8793..5ddc4b8 100644
--- a/Source/Aircraft.c
+++ b/Source/Aircraft.c
@@ -58,10 +58,10 @@ static const fix16_t AircraftSpeedsTable[] = {	0			/* IDLE */		,
  * 	Local prototypes

  * *************************************/

 

-static void AircraftDirection(TYPE_AIRCRAFT_DATA * ptrAircraft);

+static void AircraftDirection(TYPE_AIRCRAFT_DATA* ptrAircraft);

 static AIRCRAFT_LIVERY AircraftLiveryFromFlightNumber(char * strFlightNumber);

-static void AircraftAttitude(TYPE_AIRCRAFT_DATA * ptrAircraft);

-static void AircraftUpdateSpriteFromData(TYPE_AIRCRAFT_DATA * ptrAircraft);

+static void AircraftAttitude(TYPE_AIRCRAFT_DATA* ptrAircraft);

+static void AircraftUpdateSpriteFromData(TYPE_AIRCRAFT_DATA* ptrAircraft);

 

 void AircraftInit(void)

 {

@@ -96,7 +96,7 @@ bool AircraftAddNew(	TYPE_FLIGHT_DATA * ptrFlightData,
 						uint8_t FlightDataIndex,

 						uint16_t * targets		)

 {

-	TYPE_AIRCRAFT_DATA * ptrAircraft = &AircraftData[AircraftIndex];

+	TYPE_AIRCRAFT_DATA* ptrAircraft = &AircraftData[AircraftIndex];

 	uint8_t level_columns = GameGetLevelColumns();

 	uint8_t i;

 	

@@ -128,6 +128,12 @@ bool AircraftAddNew(	TYPE_FLIGHT_DATA * ptrFlightData,
 		

 		ptrAircraft->Speed = AircraftSpeedsTable[AIRCRAFT_SPEED_APPROACH];

 	}

+	else if(ptrFlightData->FlightDirection[FlightDataIndex] == DEPARTURE)

+	{

+		ptrAircraft->IsoPos.x = GameGetXFromTile(ptrFlightData->Parking[FlightDataIndex]);

+		ptrAircraft->IsoPos.y = GameGetYFromTile(ptrFlightData->Parking[FlightDataIndex]);

+		ptrAircraft->IsoPos.z = 0;

+	}

 	

 	ptrAircraft->State = ptrFlightData->State[FlightDataIndex];

 	

@@ -177,7 +183,7 @@ AIRCRAFT_LIVERY AircraftLiveryFromFlightNumber(char * strFlightNumber)
 

 void AircraftHandler(void)

 {

-	TYPE_AIRCRAFT_DATA * ptrAircraft;

+	TYPE_AIRCRAFT_DATA* ptrAircraft;

 	uint8_t i;

 	

 	for(i = 0; i < GAME_MAX_AIRCRAFT; i++)

@@ -196,7 +202,7 @@ void AircraftHandler(void)
 

 void AircraftRender(TYPE_PLAYER * ptrPlayer)

 {

-	TYPE_AIRCRAFT_DATA * ptrAircraft;

+	TYPE_AIRCRAFT_DATA* ptrAircraft;

 	TYPE_CARTESIAN_POS cartPos;

 	

 	uint8_t i;

@@ -228,7 +234,7 @@ void AircraftRender(TYPE_PLAYER * ptrPlayer)
 	}

 }

 

-void AircraftDirection(TYPE_AIRCRAFT_DATA * ptrAircraft)

+void AircraftDirection(TYPE_AIRCRAFT_DATA* ptrAircraft)

 {

 	TYPE_ISOMETRIC_FIX16_POS targetPos;

 	

@@ -291,7 +297,7 @@ void AircraftDirection(TYPE_AIRCRAFT_DATA * ptrAircraft)
 	}

 }

 

-void AircraftUpdateSpriteFromData(TYPE_AIRCRAFT_DATA * ptrAircraft)

+void AircraftUpdateSpriteFromData(TYPE_AIRCRAFT_DATA* ptrAircraft)

 {

 	switch(ptrAircraft->Livery)

 	{

@@ -331,7 +337,7 @@ void AircraftUpdateSpriteFromData(TYPE_AIRCRAFT_DATA * ptrAircraft)
 	}

 }

 

-void AircraftAttitude(TYPE_AIRCRAFT_DATA * ptrAircraft)

+void AircraftAttitude(TYPE_AIRCRAFT_DATA* ptrAircraft)

 {

 	if(ptrAircraft->State == STATE_FINAL)

 	{

@@ -347,7 +353,7 @@ TYPE_ISOMETRIC_POS AircraftGetIsoPos(uint8_t FlightDataIdx)
 	// Aircraft position data is stored in fix16_t data type instead of "short" data type.

 	// So we must perform a conversion first for convenience.

 	TYPE_ISOMETRIC_POS retIsoPos;

-	TYPE_ISOMETRIC_FIX16_POS fix16IsoPos = AircraftData[FlightDataIdx].IsoPos;

+	TYPE_ISOMETRIC_FIX16_POS fix16IsoPos = AircraftFromFlightDataIndex(FlightDataIdx)->IsoPos;

 	

 	retIsoPos.x = (short)fix16_to_int(fix16IsoPos.x);

 	retIsoPos.y = (short)fix16_to_int(fix16IsoPos.y);

@@ -356,14 +362,33 @@ TYPE_ISOMETRIC_POS AircraftGetIsoPos(uint8_t FlightDataIdx)
 	return retIsoPos;

 }

 

-void AircraftAddTargets(TYPE_AIRCRAFT_DATA * ptrAircraft, uint16_t * targets)

+void AircraftAddTargets(TYPE_AIRCRAFT_DATA* ptrAircraft, uint16_t * targets)

 {	

 	memcpy(ptrAircraft->Target, targets, sizeof(uint16_t) * AIRCRAFT_MAX_TARGETS);

 }

 

-TYPE_AIRCRAFT_DATA * AircraftFromFlightDataIndex(uint8_t index)

+uint16_t AircraftGetTileFromFlightDataIndex(uint8_t index)

+{

+	TYPE_ISOMETRIC_POS isoPos = AircraftGetIsoPos(index);

+	return GameGetTileFromIsoPosition(&isoPos);

+}

+

+TYPE_AIRCRAFT_DATA* AircraftFromFlightDataIndex(uint8_t index)

 {

-	return &AircraftData[index];

+	uint8_t i;

+	TYPE_AIRCRAFT_DATA* ptrAircraft;

+	

+	for(i = 0; i < GAME_MAX_AIRCRAFT; i++)

+	{

+		ptrAircraft = &AircraftData[i];

+		

+		if(ptrAircraft->FlightDataIdx == index)

+		{

+			return ptrAircraft;

+		}

+	}

+	

+	return NULL;

 }

 

 void AircraftFromFlightDataIndexAddTargets(uint8_t index, uint16_t * targets)

diff --git a/Source/Aircraft.h b/Source/Aircraft.h
index 2c64422..d941a13 100644
--- a/Source/Aircraft.h
+++ b/Source/Aircraft.h
@@ -17,10 +17,11 @@
 void AircraftInit(void);

 void AircraftHandler(void);

 void AircraftRender(TYPE_PLAYER * ptrPlayer);

-TYPE_AIRCRAFT_DATA * AircraftFromFlightDataIndex(uint8_t index);

+TYPE_AIRCRAFT_DATA* AircraftFromFlightDataIndex(uint8_t index);

 void AircraftFromFlightDataIndexAddTargets(uint8_t index, uint16_t * targets);

-void AircraftAddTargets(TYPE_AIRCRAFT_DATA * ptrAircraft, uint16_t * targets);

+void AircraftAddTargets(TYPE_AIRCRAFT_DATA* ptrAircraft, uint16_t * targets);

 TYPE_ISOMETRIC_POS AircraftGetIsoPos(uint8_t FlightDataIdx);

+uint16_t AircraftGetTileFromFlightDataIndex(uint8_t index);

 bool AircraftAddNew(	TYPE_FLIGHT_DATA * ptrFlightData,

 						uint8_t FlightDataIndex,

 						uint16_t * targets		);

diff --git a/Source/Game.c b/Source/Game.c
index 88d2b75..bb7e6c3 100644
--- a/Source/Game.c
+++ b/Source/Game.c
@@ -111,7 +111,6 @@ static void GameGetRunwayArray(void);
 static void GameGetSelectedRunwayArray(uint16_t rwyHeader);
 static void GameAssignRunwaytoAircraft(TYPE_PLAYER * ptrPlayer, TYPE_FLIGHT_DATA * ptrFlightData);
 static bool GameGuiShowAircraftDataSpecialConditions(TYPE_PLAYER * ptrPlayer);
-static uint16_t GameGetTileFromIsoPosition(TYPE_ISOMETRIC_POS * IsoPos);
 static bool GamePathToTile(TYPE_PLAYER * ptrPlayer);
 
 /* *************************************
@@ -195,6 +194,8 @@ void Game(bool two_players)
 		}
 	}
 	
+	GfxDisableSplitScreen();
+	
 	EndAnimation();
 	
 	SfxPlayTrack(INTRO_TRACK);
@@ -217,8 +218,8 @@ bool GamePause(void)
 		// Run player-specific functions for each player
 		if(ptrPlayer->Active == true)
 		{
-			//dprintf("Released callback = 0x%08X\n", ptrPlayer->PadKeyReleased_Callback);
-			if(ptrPlayer->PadKeyReleased_Callback(PAD_START) == true)
+			//dprintf("Released callback = 0x%08X\n", ptrPlayer->PadKeySinglePress_Callback);
+			if(ptrPlayer->PadKeySinglePress_Callback(PAD_START) == true)
 			{
 				dprintf("Player %d set pause_flag to true!\n",i);
 				pause_flag = true;
@@ -261,6 +262,7 @@ void GameInit(void)
 	PlayerData[PLAYER_ONE].Active = true;
 	PlayerData[PLAYER_ONE].PadKeyPressed_Callback = &PadOneKeyPressed;
 	PlayerData[PLAYER_ONE].PadKeyReleased_Callback = &PadOneKeyReleased;
+	PlayerData[PLAYER_ONE].PadKeySinglePress_Callback = &PadOneKeySinglePress;
 	PlayerData[PLAYER_ONE].PadDirectionKeyPressed_Callback = &PadOneDirectionKeyPressed;
 	PlayerData[PLAYER_ONE].FlightDataPage = 0;
 	
@@ -272,6 +274,7 @@ void GameInit(void)
 		PlayerData[PLAYER_TWO].PadKeyReleased_Callback = &PadTwoKeyReleased;
 		PlayerData[PLAYER_TWO].PadDirectionKeyPressed_Callback = &PadTwoDirectionKeyPressed;
 		PlayerData[PLAYER_TWO].FlightDataPage = 0;
+		PlayerData[PLAYER_TWO].PadKeySinglePress_Callback = &PadTwoKeySinglePress;
 		
 		// On 2-player mode, one player controls departure flights and
 		// other player controls arrival flights.
@@ -549,12 +552,18 @@ void GameClockFlights(void)
 void GameGraphics(void)
 {
 	int i;
+	bool split_screen = false;
 	
 	while(	(GfxIsGPUBusy() == true)
 					||
 			(SystemRefreshNeeded() == false)	);
-
-	GsSortCls(0,0,NORMAL_LUMINANCE >> 1);
+			
+	if( (PlayerData[PLAYER_ONE].Active == true)
+						&&
+		(PlayerData[PLAYER_TWO].Active == true) )
+	{
+		split_screen = true;
+	}
 	
 	if(GfxGetGlobalLuminance() < NORMAL_LUMINANCE)
 	{
@@ -564,24 +573,34 @@ void GameGraphics(void)
 	for(i = 0; i < MAX_PLAYERS ; i++)
 	{
 		if(PlayerData[i].Active == true)
-		{
+		{	
+			if(split_screen == true)
+			{
+				GfxSetSplitScreen(i);
+			}
+			
+			GsSortCls(0,0,GfxGetGlobalLuminance() >> 1);
+
 			GameRenderLevel(&PlayerData[i]);
 			AircraftRender(&PlayerData[i]);
-		}
-	}
-	
-	GameGuiAircraftNotificationRequest(&FlightData);
-	
-	GameGuiBubble(&FlightData);
-	
-	GameGuiClock(GameHour,GameMinutes);
+			
+			GameGuiAircraftNotificationRequest(&FlightData);
 	
-	for(i = 0; i < MAX_PLAYERS ; i++)
-	{
-		GameGuiAircraftList(&PlayerData[i], &FlightData);
+			GameGuiBubble(&FlightData);
+			
+			GameGuiClock(GameHour,GameMinutes);
+			
+			/*for(i = 0; i < MAX_PLAYERS ; i++)
+			{*/
+				GameGuiAircraftList(&PlayerData[i], &FlightData);
+			//}
+			
+			GfxDrawScene_Fast();
+			while(GfxIsGPUBusy() == true);
+		}
 	}
 	
-	GfxDrawScene();	
+	SystemCyclicHandler();
 }
 
 void GameLoadLevel(void)
@@ -658,6 +677,11 @@ char* GetGameLevelTitle(void)
 void GameAircraftState(void)
 {
 	uint8_t i;
+	uint16_t target[2] = {0};
+	// Arrays are copied to AircraftAddNew, so we create a first and only
+	// target which is the parking tile itself, and the second element
+	// is just the NULL character.
+	// Not an ideal solution, but the best one currently available.
 	
 	for(i = 0; i < FlightData.nAircraft ; i++)
 	{
@@ -670,6 +694,16 @@ void GameAircraftState(void)
 			if(FlightData.FlightDirection[i] == DEPARTURE)
 			{
 				FlightData.State[i] = STATE_PARKED;
+				
+				target[0] = FlightData.Parking[i];
+				
+				dprintf("Target assigned = %d", target[0]);
+				
+				if(AircraftAddNew(&FlightData, i, target) == false)
+				{
+					dprintf("Exceeded maximum aircraft number!\n");
+					return;
+				}
 			}
 			else if(FlightData.FlightDirection[i] == ARRIVAL)
 			{
@@ -947,11 +981,11 @@ void GameStateShowAircraft(TYPE_PLAYER * ptrPlayer, TYPE_FLIGHT_DATA * ptrFlight
 {
 	if(ptrPlayer->ShowAircraftData == true)
 	{
-		if(ptrPlayer->PadKeyReleased_Callback(PAD_TRIANGLE) == true)
+		if(ptrPlayer->PadKeySinglePress_Callback(PAD_TRIANGLE) == true)
 		{
 			ptrPlayer->ShowAircraftData = false;
 		}
-		else if(ptrPlayer->PadKeyReleased_Callback(PAD_SQUARE) == true)
+		else if(ptrPlayer->PadKeySinglePress_Callback(PAD_SQUARE) == true)
 		{
 			dprintf("Aircraft state = %d. STATE_IDLE = %d\n",
 					ptrFlightData->State[ptrPlayer->SelectedAircraft],
@@ -965,7 +999,7 @@ void GameStateShowAircraft(TYPE_PLAYER * ptrPlayer, TYPE_FLIGHT_DATA * ptrFlight
 		}
 	}
 	
-	if(ptrPlayer->PadKeyReleased_Callback(PAD_CIRCLE) == true)
+	if(ptrPlayer->PadKeySinglePress_Callback(PAD_CIRCLE) == true)
 	{
 		if(GameGuiShowAircraftDataSpecialConditions(ptrPlayer) == false)
 		{
@@ -981,7 +1015,7 @@ void GameStateLockTarget(TYPE_PLAYER * ptrPlayer)
 	{
 		CameraMoveToIsoPos(ptrPlayer, AircraftGetIsoPos(ptrPlayer->LockedAircraft) );
 		
-		if(ptrPlayer->PadKeyReleased_Callback(PAD_SQUARE) == true)
+		if(ptrPlayer->PadKeySinglePress_Callback(PAD_SQUARE) == true)
 		{
 			ptrPlayer->LockTarget = false;
 			ptrPlayer->LockedAircraft = 0;
@@ -1010,7 +1044,7 @@ void GameStateSelectTaxiwayRunway(TYPE_PLAYER * ptrPlayer, TYPE_FLIGHT_DATA * pt
 			ptrPlayer->InvalidPath = true;
 		}
 		
-		if(ptrPlayer->PadKeyReleased_Callback(PAD_TRIANGLE) == true)
+		if(ptrPlayer->PadKeySinglePress_Callback(PAD_TRIANGLE) == true)
 		{
 			// State exit.
 			ptrPlayer->SelectTaxiwayRunway = false;
@@ -1019,7 +1053,7 @@ void GameStateSelectTaxiwayRunway(TYPE_PLAYER * ptrPlayer, TYPE_FLIGHT_DATA * pt
 			ptrPlayer->WaypointIdx = 0;
 			ptrPlayer->LastWaypointIdx = 0;
 		}
-		else if(ptrPlayer->PadKeyReleased_Callback(PAD_CROSS) == true)
+		else if(ptrPlayer->PadKeySinglePress_Callback(PAD_CROSS) == true)
 		{
 			if(ptrPlayer->InvalidPath == false)
 			{
@@ -1035,32 +1069,36 @@ void GameStateSelectTaxiwayRunway(TYPE_PLAYER * ptrPlayer, TYPE_FLIGHT_DATA * pt
 				
 				target_tile = GameLevelBuffer[ptrPlayer->Waypoints[ptrPlayer->LastWaypointIdx]];
 				
-				if(	(target_tile == TILE_RWY_START_1)
-										||
-					(target_tile == (TILE_RWY_START_1 | TILE_MIRROR_FLAG) )
-										||
-					(target_tile == TILE_RWY_START_2)
-										||
-					(target_tile == (TILE_RWY_START_2 | TILE_MIRROR_FLAG) ) )
+				switch(target_tile)
 				{
-					// TODO: Assign path to aircraft
-					AircraftFromFlightDataIndexAddTargets(ptrPlayer->LockedAircraft, ptrPlayer->Waypoints);
-					dprintf("Added these targets to aircraft %d:\n", ptrPlayer->LockedAircraft);
-					
-					for(i = 0; i < PLAYER_MAX_WAYPOINTS; i++)
-					{
-						dprintf("%d ",ptrPlayer->Waypoints[i]);
-					}
-					
-					dprintf("\n");
-					
-					ptrPlayer->SelectTaxiwayParking = false;
-					// Clear waypoints array.
-					memset(ptrPlayer->Waypoints, 0, sizeof(uint16_t) * PLAYER_MAX_WAYPOINTS);
-					ptrPlayer->WaypointIdx = 0;
-					ptrPlayer->LastWaypointIdx = 0;
+					case TILE_RWY_START_1:
+						// Fall through
+					case TILE_RWY_START_1 | TILE_MIRROR_FLAG:
+						// Fall through
+					case TILE_RWY_START_2:
+						// Fall through
+					case TILE_RWY_START_2 | TILE_MIRROR_FLAG:
+						AircraftFromFlightDataIndexAddTargets(ptrPlayer->LockedAircraft, ptrPlayer->Waypoints);
+						dprintf("Added these targets to aircraft %d:\n", ptrPlayer->LockedAircraft);
+						
+						for(i = 0; i < PLAYER_MAX_WAYPOINTS; i++)
+						{
+							dprintf("%d ",ptrPlayer->Waypoints[i]);
+						}
+						
+						dprintf("\n");
+						
+						ptrPlayer->SelectTaxiwayParking = false;
+						// Clear waypoints array.
+						memset(ptrPlayer->Waypoints, 0, sizeof(uint16_t) * PLAYER_MAX_WAYPOINTS);
+						ptrPlayer->WaypointIdx = 0;
+						ptrPlayer->LastWaypointIdx = 0;
+						
+						ptrFlightData->State[ptrPlayer->LockedAircraft] = STATE_TAXIING;
+					break;
 					
-					ptrFlightData->State[ptrPlayer->LockedAircraft] = STATE_TAXIING;
+					default:
+					break;
 				}
 			}
 		}
@@ -1086,7 +1124,7 @@ void GameStateSelectTaxiwayParking(TYPE_PLAYER * ptrPlayer, TYPE_FLIGHT_DATA * p
 			ptrPlayer->InvalidPath = true;
 		}
 		
-		if(ptrPlayer->PadKeyReleased_Callback(PAD_TRIANGLE) == true)
+		if(ptrPlayer->PadKeySinglePress_Callback(PAD_TRIANGLE) == true)
 		{
 			// State exit.
 			ptrPlayer->SelectTaxiwayParking = false;
@@ -1095,7 +1133,7 @@ void GameStateSelectTaxiwayParking(TYPE_PLAYER * ptrPlayer, TYPE_FLIGHT_DATA * p
 			ptrPlayer->WaypointIdx = 0;
 			ptrPlayer->LastWaypointIdx = 0;
 		}
-		else if(ptrPlayer->PadKeyReleased_Callback(PAD_CROSS) == true)
+		else if(ptrPlayer->PadKeySinglePress_Callback(PAD_CROSS) == true)
 		{
 			if(ptrPlayer->InvalidPath == false)
 			{
@@ -1158,11 +1196,11 @@ void GameStateSelectRunway(TYPE_PLAYER * ptrPlayer, TYPE_FLIGHT_DATA * ptrFlight
 		ptrPlayer->LockTarget = false;
 		ptrPlayer->LockedAircraft = 0;
 		
-		if(ptrPlayer->PadKeyReleased_Callback(PAD_TRIANGLE) == true)
+		if(ptrPlayer->PadKeySinglePress_Callback(PAD_TRIANGLE) == true)
 		{
 			ptrPlayer->SelectRunway = false;
 		}
-		else if(ptrPlayer->PadKeyReleased_Callback(PAD_CROSS) == true)
+		else if(ptrPlayer->PadKeySinglePress_Callback(PAD_CROSS) == true)
 		{
 			ptrPlayer->SelectRunway = false;
 			
@@ -1191,14 +1229,14 @@ void GameStateSelectRunway(TYPE_PLAYER * ptrPlayer, TYPE_FLIGHT_DATA * ptrFlight
 				}
 			}
 		}
-		else if(ptrPlayer->PadKeyReleased_Callback(PAD_LEFT) == true)
+		else if(ptrPlayer->PadKeySinglePress_Callback(PAD_LEFT) == true)
 		{
 			if(ptrPlayer->SelectedRunway != 0)
 			{
 				ptrPlayer->SelectedRunway--;
 			}
 		}
-		else if(ptrPlayer->PadKeyReleased_Callback(PAD_RIGHT) == true)
+		else if(ptrPlayer->PadKeySinglePress_Callback(PAD_RIGHT) == true)
 		{
 			if(ptrPlayer->SelectedRunway < GAME_MAX_RUNWAYS)
 			{
@@ -1248,7 +1286,7 @@ void GameSelectAircraftFromList(TYPE_PLAYER * ptrPlayer, TYPE_FLIGHT_DATA * ptrF
 	
 	if(ptrPlayer->ShowAircraftData == true)
 	{
-		if(ptrPlayer->PadKeyReleased_Callback(PAD_CROSS) == true)
+		if(ptrPlayer->PadKeySinglePress_Callback(PAD_CROSS) == true)
 		{
 			if(ptrPlayer->ActiveAircraft != 0)
 			{
@@ -1467,6 +1505,10 @@ void GameTargetsReached(uint8_t index)
 			FlightData.State[index] = STATE_LANDED;
 		break;
 		
+		case STATE_TAXIING:
+			FlightData.State[index] = STATE_PARKED;
+		break;
+		
 		default:
 		break;
 	}
@@ -1492,6 +1534,11 @@ uint16_t GameGetTileFromIsoPosition(TYPE_ISOMETRIC_POS * IsoPos)
 {
 	uint16_t tile;
 	
+	if(IsoPos == NULL)
+	{
+		return 0;
+	}
+	
 	if(	(IsoPos->x < 0) || (IsoPos->y < 0) )
 	{
 		return GAME_INVALID_TILE_SELECTION; // Invalid XYZ position
@@ -1613,8 +1660,20 @@ bool GamePathToTile(TYPE_PLAYER * ptrPlayer)
 			
 			if(SystemContains_u16(temp_tile, ptrPlayer->Waypoints, PLAYER_MAX_WAYPOINTS) == false)
 			{
+				for(i = 0; i < GAME_MAX_AIRCRAFT; i++)
+				{
+					if(temp_tile == AircraftGetTileFromFlightDataIndex(i))
+					{
+						return false;	// Check pending!
+					}
+				}
+				
 				GamePlayerAddWaypoint_Ex(ptrPlayer, temp_tile);
 			}
+			else
+			{
+				return false;	// Tile is already included in the list of temporary tiles?
+			}
 		}
 		
 		while( (y_diff--) > 0)
@@ -1631,8 +1690,21 @@ bool GamePathToTile(TYPE_PLAYER * ptrPlayer)
 			
 			if(SystemContains_u16(temp_tile, ptrPlayer->Waypoints, PLAYER_MAX_WAYPOINTS) == false)
 			{
+				for(i = 0; i < GAME_MAX_AIRCRAFT; i++)
+				{
+					if(temp_tile == AircraftGetTileFromFlightDataIndex(i))
+					{
+						return false;	// Check pending!
+					}
+				}
+				
 				GamePlayerAddWaypoint_Ex(ptrPlayer, temp_tile);
 			}
+			else
+			{
+				// TEST - Check pending!
+				return false;	// Tile is already included in the list of temporary tiles?
+			}
 		}
 	}
 	else
@@ -1651,8 +1723,21 @@ bool GamePathToTile(TYPE_PLAYER * ptrPlayer)
 			
 			if(SystemContains_u16(temp_tile, ptrPlayer->Waypoints, PLAYER_MAX_WAYPOINTS) == false)
 			{
+				for(i = 0; i < GAME_MAX_AIRCRAFT; i++)
+				{
+					if(temp_tile == AircraftGetTileFromFlightDataIndex(i))
+					{
+						return false;	// Check pending!
+					}
+				}
+				
 				GamePlayerAddWaypoint_Ex(ptrPlayer, temp_tile);
 			}
+			else
+			{
+				// TEST - Check pending!
+				return false;	// Tile is already included in the list of temporary tiles?
+			}
 		}
 		
 		while( (x_diff--) > 0)
@@ -1669,8 +1754,21 @@ bool GamePathToTile(TYPE_PLAYER * ptrPlayer)
 			
 			if(SystemContains_u16(temp_tile, ptrPlayer->Waypoints, PLAYER_MAX_WAYPOINTS) == false)
 			{
+				for(i = 0; i < GAME_MAX_AIRCRAFT; i++)
+				{
+					if(temp_tile == AircraftGetTileFromFlightDataIndex(i))
+					{
+						return false;	// Check pending!
+					}
+				}
+
 				GamePlayerAddWaypoint_Ex(ptrPlayer, temp_tile);
 			}
+			else
+			{
+				// TEST - Check pending!
+				return false;	// Tile is already included in the list of temporary tiles?
+			}
 		}
 	}
 	
diff --git a/Source/Game.h b/Source/Game.h
index 8bccf63..712c404 100644
--- a/Source/Game.h
+++ b/Source/Game.h
@@ -44,5 +44,6 @@ uint8_t 	GameGetLevelColumns(void);
 fix16_t 	GameGetXFromTile(uint16_t tile);
 fix16_t 	GameGetYFromTile(uint16_t tile);
 void 		GameTargetsReached(uint8_t index);
+uint16_t	GameGetTileFromIsoPosition(TYPE_ISOMETRIC_POS * IsoPos);
 
 #endif //__GAME_HEADER__
diff --git a/Source/GameGui.c b/Source/GameGui.c
index 47d6c37..dc13e6c 100644
--- a/Source/GameGui.c
+++ b/Source/GameGui.c
@@ -336,7 +336,7 @@ bool GameGuiPauseDialog(TYPE_PLAYER * ptrPlayer)
 	

 	do

 	{

-		if(ptrPlayer->PadKeyReleased_Callback(PAD_CROSS) == true)

+		if(ptrPlayer->PadKeySinglePress_Callback(PAD_CROSS) == true)

 		{

 			return true;

 		}

@@ -347,7 +347,7 @@ bool GameGuiPauseDialog(TYPE_PLAYER * ptrPlayer)
 		

 		GfxDrawScene_Slow();

 		

-	}while(ptrPlayer->PadKeyReleased_Callback(PAD_START) == false);

+	}while(ptrPlayer->PadKeySinglePress_Callback(PAD_START) == false);

 	

 	return false;

 }

@@ -388,7 +388,7 @@ void GameGuiActiveAircraftPage(TYPE_PLAYER * ptrPlayer, TYPE_FLIGHT_DATA * ptrFl
 	

 	if(ptrPlayer->ShowAircraftData == true)

 	{

-		if(ptrPlayer->PadKeyReleased_Callback(PAD_DOWN) == true)

+		if(ptrPlayer->PadKeySinglePress_Callback(PAD_DOWN) == true)

 		{

 			if( ( (ptrPlayer->SelectedAircraft + 1) < ptrPlayer->ActiveAircraft)

 												&&

@@ -398,7 +398,7 @@ void GameGuiActiveAircraftPage(TYPE_PLAYER * ptrPlayer, TYPE_FLIGHT_DATA * ptrFl
 			}

 		}

 		

-		if(ptrPlayer->PadKeyReleased_Callback(PAD_UP) == true)

+		if(ptrPlayer->PadKeySinglePress_Callback(PAD_UP) == true)

 		{

 			if(ptrPlayer->SelectedAircraft > ( (ptrPlayer->FlightDataPage) * GAME_GUI_AIRCRAFT_DATA_MAX_PAGE) )

 			{

@@ -406,7 +406,7 @@ void GameGuiActiveAircraftPage(TYPE_PLAYER * ptrPlayer, TYPE_FLIGHT_DATA * ptrFl
 			}

 		}

 		

-		if(ptrPlayer->PadKeyReleased_Callback(PAD_RIGHT) == true)

+		if(ptrPlayer->PadKeySinglePress_Callback(PAD_RIGHT) == true)

 		{

 			if(ptrPlayer->ActiveAircraft > (GAME_GUI_AIRCRAFT_DATA_MAX_PAGE * (ptrPlayer->FlightDataPage + 1) ) )

 			{

@@ -416,7 +416,7 @@ void GameGuiActiveAircraftPage(TYPE_PLAYER * ptrPlayer, TYPE_FLIGHT_DATA * ptrFl
 			}

 		}

 		

-		if(ptrPlayer->PadKeyReleased_Callback(PAD_LEFT) == true)

+		if(ptrPlayer->PadKeySinglePress_Callback(PAD_LEFT) == true)

 		{

 			if(ptrPlayer->FlightDataPage != 0)

 			{

@@ -544,7 +544,7 @@ void GameGuiAircraftList(TYPE_PLAYER * ptrPlayer, TYPE_FLIGHT_DATA * ptrFlightDa
 			{

 				FontPrintText( 	&SmallFont,

 								AIRCRAFT_DATA_GSGPOLY4_X0 + 

-								( (AIRCRAFT_DATA_GSGPOLY4_X1 - AIRCRAFT_DATA_GSGPOLY4_X0) >> 1),

+								( (AIRCRAFT_DATA_GSGPOLY4_X1 - AIRCRAFT_DATA_GSGPOLY4_X0) >> 2),

 								AIRCRAFT_DATA_GSGPOLY4_Y0 +

 								( (AIRCRAFT_DATA_GSGPOLY4_Y2 - AIRCRAFT_DATA_GSGPOLY4_Y0) >> 1),

 								"No flights!"	);

@@ -696,25 +696,32 @@ void GameGuiShowAircraftData(TYPE_PLAYER * ptrPlayer, TYPE_FLIGHT_DATA * ptrFlig
 		{

 			case STATE_FINAL:

 				FontPrintText(	&SmallFont,

-								AIRCRAFT_DATA_DIRECTION_X + 64,

+								AIRCRAFT_DATA_DIRECTION_X + 88,

 								AIRCRAFT_DATA_DIRECTION_Y + (AIRCRAFT_DATA_FLIGHT_GSGPOLY4_H * j),

 								"Landing"	);

 			break;

 			

 			case STATE_TAXIING:

 				FontPrintText(	&SmallFont,

-								AIRCRAFT_DATA_DIRECTION_X + 64,

+								AIRCRAFT_DATA_DIRECTION_X + 88,

 								AIRCRAFT_DATA_DIRECTION_Y + (AIRCRAFT_DATA_FLIGHT_GSGPOLY4_H * j),

 								"Taxiing"	);

 			break;

 			

 			case STATE_LANDED:

 				FontPrintText(	&SmallFont,

-								AIRCRAFT_DATA_DIRECTION_X + 64,

+								AIRCRAFT_DATA_DIRECTION_X + 88,

 								AIRCRAFT_DATA_DIRECTION_Y + (AIRCRAFT_DATA_FLIGHT_GSGPOLY4_H * j),

 								"Arrived"	);

 			break;

 			

+			case STATE_PARKED:

+				FontPrintText(	&SmallFont,

+								AIRCRAFT_DATA_DIRECTION_X + 88,

+								AIRCRAFT_DATA_DIRECTION_Y + (AIRCRAFT_DATA_FLIGHT_GSGPOLY4_H * j),

+								"Parked"	);

+			break;

+			

 			default:

 			break;

 		}

diff --git a/Source/GameStructures.h b/Source/GameStructures.h
index 4baa03a..3efe573 100644
--- a/Source/GameStructures.h
+++ b/Source/GameStructures.h
@@ -159,6 +159,7 @@ typedef struct
 	

 	bool	(*PadKeyPressed_Callback)(unsigned short);

 	bool	(*PadKeyReleased_Callback)(unsigned short);

+	bool	(*PadKeySinglePress_Callback)(unsigned short);

 	bool	(*PadDirectionKeyPressed_Callback)(void);

 	TYPE_CAMERA Camera;

 }TYPE_PLAYER;

diff --git a/Source/Gfx.c b/Source/Gfx.c
index a976b00..329ba19 100644
--- a/Source/Gfx.c
+++ b/Source/Gfx.c
@@ -13,6 +13,7 @@
 #define UPLOAD_IMAGE_FLAG 1
 #define MAX_LUMINANCE 0xFF
 #define ROTATE_BIT_SHIFT 12
+#define GPUSTAT (*(unsigned int*)0x1F801814)
 
 /* *************************************
  * 	Structs and enums
@@ -87,7 +88,6 @@ void GfxSwapBuffers(void)
 		GsSetDispEnv(&DispEnv);
 		GsSetDrawEnv(&DrawEnv);
 	}
-
 }
 
 
@@ -122,34 +122,20 @@ void GfxDrawScene_Fast(void)
 	GsDrawList();
 }
 
+bool GfxReadyForDMATransfer(void)
+{
+	return (GPUSTAT & 1<<28);
+}
+
 void GfxDrawScene(void)
 {
 	while(	(SystemRefreshNeeded() == false) 
 				||
-			(GsIsDrawing() == true)
-				||
-			(SystemDMAReady() == false)		);
+			(GfxIsGPUBusy() == true)		);
 			
 	GfxDrawScene_Fast();
 	
-	if(UpdatePads() == false)
-	{
-		SystemSetEmergencyMode(true);
-	}
-	else
-	{
-		SystemSetEmergencyMode(false);
-	}
-	
-	SystemRunTimers();
-	
-	SystemUserTimersHandler();
-	
-	SystemDisableScreenRefresh();
-	
-	MemCardHandler();
-	
-	SystemCheckStack();
+	SystemCyclicHandler();
 }
 
 void GfxDrawScene_Slow(void)
@@ -283,7 +269,7 @@ int GfxRotateFromDegrees(int deg)
 
 bool GfxIsGPUBusy(void)
 {
-	return (GsIsDrawing() || gfx_busy || SystemDMABusy() );
+	return (GsIsDrawing() || gfx_busy || (GfxReadyForDMATransfer() == false) );
 }
 
 bool GfxSpriteFromFile(char * fname, GsSprite * spr)
@@ -416,6 +402,8 @@ void GfxDrawButton(short x, short y, unsigned short btn)
 
 void GfxSaveDisplayData(GsSprite *spr)
 {
+	while(GfxIsGPUBusy() == true);
+	
 	MoveImage(	DispEnv.x,
 				DispEnv.y,
 				GFX_SECOND_DISPLAY_X,
@@ -524,3 +512,40 @@ TYPE_ISOMETRIC_POS GfxCartesianToIsometric(TYPE_CARTESIAN_POS * ptrCartPos)
 	
 	return IsoPos;
 }
+
+void GfxSetSplitScreen(uint8_t playerIndex)
+{
+	
+	switch(playerIndex)
+	{
+		case 0:
+			// PLAYER_ONE
+			DrawEnv.x = 0;
+			DrawEnv.w = X_SCREEN_RESOLUTION >> 1;
+		break;
+		
+		case 1:
+			// PLAYER_TWO
+			DrawEnv.x = X_SCREEN_RESOLUTION >> 1;
+			DrawEnv.w = X_SCREEN_RESOLUTION >> 1;
+		break;
+		
+		default:
+		break;
+	}
+	
+	dprintf("Player idx = %d, x = %d, w = %d\n",
+			playerIndex,
+			DrawEnv.x,
+			DrawEnv.w);
+	
+	GsSetDrawEnv(&DrawEnv);
+}
+
+void GfxDisableSplitScreen(void)
+{
+	DrawEnv.x = 0;
+	DrawEnv.w = X_SCREEN_RESOLUTION;
+	
+	GsSetDrawEnv(&DrawEnv);
+}
diff --git a/Source/Gfx.h b/Source/Gfx.h
index b9984ee..68c0f5b 100644
--- a/Source/Gfx.h
+++ b/Source/Gfx.h
@@ -32,43 +32,73 @@
 void GfxInitDrawEnv(void);
 void GfxInitDispEnv(void);
 void GfxSetPrimitiveList(void);
+
 // Renders new scene. Use this function unless you know what you are doing!
 void GfxDrawScene(void);
+
 // Blocking version. Calls GfxDrawScene() and then adds a while(GfxIsBusy() )
 // after it.
 void GfxDrawScene_Slow(void);
+
 // Only renders screen and does not update any pad data or timer data.
 // To be used in ISR!
 void GfxDrawScene_Fast(void);
+
+// Repotedly, tells is GPU is ready for a DMA transfer.
+bool GfxReadyForDMATransfer(void);
+
 // Fills a GsSprite structure with information from a TIM file.
 bool GfxSpriteFromFile(char * fname, GsSprite * spr);
+
 // Reportedly, loads CLUT data from a TIM image (image data is discarded)
 bool GfxCLUTFromFile(char * fname);
+
 // Returns true if current object is within screen limits, false otherwise.
 bool GfxIsInsideScreenArea(short x, short y, short w, short h);
+
 // Function overload for GsSprite structures.
 bool GfxIsSpriteInsideScreenArea(GsSprite * spr);
+
 // Used to know whether GPU operation can be done.
 bool GfxIsGPUBusy(void);
+
+// Draws a sprite on screen. First, it checks whether sprite is inside
+// screen limits.
 void GfxSortSprite(GsSprite * spr);
+
 uint8_t GfxGetGlobalLuminance(void);
+
 void GfxSetGlobalLuminance(uint8_t value);
+
 void GfxIncreaseGlobalLuminance(int8_t step);
+
 int GfxRotateFromDegrees(int deg);
+
 void GfxDrawButton(short x, short y, unsigned short btn);
+
 // Sends current display data on a specific VRAM section and fills
 // sprite structure pointed to by "spr".
 void GfxSaveDisplayData(GsSprite *spr);
+
 TYPE_CARTESIAN_POS GfxIsometricToCartesian(TYPE_ISOMETRIC_POS * ptrIsoPos);
 // Function overload for fixed-point 16.16 data type.
+
 TYPE_CARTESIAN_POS GfxIsometricFix16ToCartesian(TYPE_ISOMETRIC_FIX16_POS * ptrIso16Pos);
+
 // Transforms cartesian position to isometric position. Z axis is assumed to be zero!
 TYPE_ISOMETRIC_POS GfxCartesianToIsometric(TYPE_CARTESIAN_POS * ptrCartPos);
+
 // Fills GsSprite structure pointed to by "spr" with texture page and U/V
 // offset data given a position in VRAM.
 bool GfxTPageOffsetFromVRAMPosition(GsSprite * spr, short x, short y);
+
+void GfxSetSplitScreen(uint8_t playerIndex);
+
+void GfxDisableSplitScreen(void);
+
 // Switches between true and false every 1 exact second (used for flashing effects)
 bool Gfx1HzFlash(void);
+
 // Switches between true and false every 500 milliseconds (used for flashing effects)
 bool Gfx2HzFlash(void);
 
diff --git a/Source/Makefile b/Source/Makefile
index 3e96e0b..96c3f7d 100644
--- a/Source/Makefile
+++ b/Source/Makefile
@@ -47,7 +47,7 @@ $(OBJ_DIR)/%.o: $(SRC_DIR)/%.c
 	$(CC) $< -o $@ $(DEFINE) $(CC_FLAGS)
 	
 $(PROJECT).elf: 
-	$(LINKER) Obj/*.o -o Exe/$(PROJECT).elf $(LIBS)
+	$(LINKER) Obj/*.o -o Exe/$(PROJECT).elf $(LIBS) -Wl,--gc-sections
 	
 $(PROJECT).exe:
 	$(ELF2EXE) Exe/$(PROJECT).elf Exe/$(PROJECT).exe $(ELF2EXE_FLAGS)
diff --git a/Source/Menu.c b/Source/Menu.c
index 411c276..32d0e45 100644
--- a/Source/Menu.c
+++ b/Source/Menu.c
@@ -121,10 +121,13 @@ static char * MainMenuFiles[] = {	"cdrom:\\DATA\\SPRITES\\MAINMENU.TIM;1"	,
 									"cdrom:\\DATA\\SPRITES\\PSXDISK.TIM;1"	,
 									"cdrom:\\DATA\\SPRITES\\INTROFNT.TIM;1"	,
 									"cdrom:\\DATA\\SPRITES\\BUTTONS.TIM;1"	,
+#ifndef NO_INTRO
 									"cdrom:\\DATA\\SPRITES\\GPL.TIM;1"		,
 									"cdrom:\\DATA\\SPRITES\\OPENSRC.TIM;1"	,
 									"cdrom:\\DATA\\SOUNDS\\TRAYCL.VAG;1"	,
-									"cdrom:\\DATA\\SOUNDS\\SPINDISK.VAG;1"	};
+									"cdrom:\\DATA\\SOUNDS\\SPINDISK.VAG;1"	
+#endif // NO_INTRO
+									};
 									
 static void * MainMenuDest[] = {	(GsSprite*)&MenuSpr			,
 									(SsVag*)&BellSnd			,
@@ -132,10 +135,13 @@ static void * MainMenuDest[] = {	(GsSprite*)&MenuSpr			,
 									(GsSprite*)&PsxDisk			,
 									(GsSprite*)&PSXSDKIntroFont	,
 									(GsSprite*)&PSXButtons		,
+#ifndef NO_INTRO
 									(GsSprite*)&GPL_Logo		,
 									(GsSprite*)&OpenSource_Logo	,
 									(SsVag*)&TrayClSnd			,
-									(SsVag*)&SpinDiskSnd		};
+									(SsVag*)&SpinDiskSnd		
+#endif // NO_INTRO
+									};
 
 static TYPE_MMBtn MainMenuBtn[MAIN_MENU_BUTTONS_MAX];
 static MainMenuLevel menuLevel;
@@ -254,12 +260,13 @@ void MainMenu(void)
 	
 	while(1)
 	{
+		while(GfxIsGPUBusy() == true);
+		
 		MainMenuButtonHandler();
 		
 		switch(menuLevel)
 		{
 			case PLAY_OPTIONS_LEVEL:
-				while(SystemDMAReady() == false);
 				
 				GsSortCls(0,0,40);				
 				MainMenuDrawButton(&MainMenuBtn[PLAY_BUTTON_INDEX]);
@@ -269,7 +276,6 @@ void MainMenu(void)
 			break;
 			
 			case ONE_TWO_PLAYERS_LEVEL:
-				while(SystemDMAReady() == false);
 				
 				GsSortCls(0,0,40);				
 				MainMenuDrawButton(&MainMenuBtn[ONE_PLAYER_BUTTON_INDEX]);
@@ -320,9 +326,9 @@ void MainMenuButtonHandler(void)
 		}
 	}
 	
-	if(	(PadOneKeyReleased(PAD_CROSS) == true)
+	if(	(PadOneKeySinglePress(PAD_CROSS) == true)
 				||
-		(PadOneKeyReleased(PAD_TRIANGLE) == true)	)
+		(PadOneKeySinglePress(PAD_TRIANGLE) == true)	)
 	{
 		SfxPlaySound(&AcceptSnd);
 	}
@@ -335,7 +341,7 @@ void MainMenuButtonHandler(void)
 		
 		case ONE_TWO_PLAYERS_LEVEL:
 			max_buttons = MAIN_MENU_ONE_TWO_PLAYERS_LEVEL_BUTTONS;
-			if(PadOneKeyReleased(PAD_TRIANGLE) == true)
+			if(PadOneKeySinglePress(PAD_TRIANGLE) == true)
 			{
 				menuLevel = PLAY_OPTIONS_LEVEL;
 				MainMenuMinimumBtn = PLAY_BUTTON_INDEX;
@@ -351,14 +357,14 @@ void MainMenuButtonHandler(void)
 	MainMenuBtn[previous_btn_selected].was_selected = MainMenuBtn[previous_btn_selected].selected;
 	MainMenuBtn[btn_selected].was_selected = MainMenuBtn[btn_selected].selected;
 	
-	if(PadOneKeyReleased(PAD_LEFT)	&& (btn_selected > 0) )
+	if(PadOneKeySinglePress(PAD_LEFT)	&& (btn_selected > 0) )
 	{
 		MainMenuBtn[btn_selected].selected = false;
 		previous_btn_selected = btn_selected;
 		btn_selected--;
 		SfxPlaySound(&BellSnd);
 	}
-	else if(PadOneKeyReleased(PAD_RIGHT) 
+	else if(PadOneKeySinglePress(PAD_RIGHT) 
 				&&
 			(btn_selected < (max_buttons - 1 + MainMenuMinimumBtn) ) )
 	{
@@ -379,7 +385,7 @@ void MainMenuButtonHandler(void)
 		btn_selected = (max_buttons - 1 + MainMenuMinimumBtn);
 	}
 	
-	if(PadOneKeyReleased(PAD_CROSS) )
+	if(PadOneKeySinglePress(PAD_CROSS) )
 	{
 		if(menuLevel == ONE_TWO_PLAYERS_LEVEL)
 		{
diff --git a/Source/Pad.c b/Source/Pad.c
index 7fc08a2..2a84304 100644
--- a/Source/Pad.c
+++ b/Source/Pad.c
@@ -177,6 +177,16 @@ bool PadTwoKeyPressed(unsigned short key)
 	return (bool)( pad2 & key );
 }
 
+bool PadOneKeySinglePress(unsigned short key)
+{
+	return (bool)( !(previous_pad1 & key) && (pad1 & key) );
+}
+
+bool PadTwoKeySinglePress(unsigned short key)
+{
+	return (bool)( !(previous_pad2 & key) && (pad2 & key) );
+}
+
 bool PadOneKeyRepeat(unsigned short key, uint8_t time)
 {
 	uint8_t key_index = PadGetKeyIndex(key);
diff --git a/Source/Pad.h b/Source/Pad.h
index 3e0ff69..5e5588b 100644
--- a/Source/Pad.h
+++ b/Source/Pad.h
@@ -36,6 +36,9 @@ bool PadTwoKeyRepeat(unsigned short key, uint8_t time);
 bool PadOneKeyReleased(unsigned short key);
 bool PadTwoKeyReleased(unsigned short key);
 
+bool PadOneKeySinglePress(unsigned short key);
+bool PadTwoKeySinglePress(unsigned short key);
+
 bool PadOneDirectionKeyPressed(void);
 bool PadTwoDirectionKeyPressed(void);
 
diff --git a/Source/System.c b/Source/System.c
index b158004..833c80f 100644
--- a/Source/System.c
+++ b/Source/System.c
@@ -14,6 +14,7 @@
 #define END_STACK_PATTERN (uint32_t) 0x18022015
 #define BEGIN_STACK_ADDRESS (uint32_t*) 0x801FFF00
 #define STACK_SIZE 0x1000
+#define I_MASK (*(unsigned int*)0x1F801074)
 
 /* *************************************
  * 	Local Prototypes
@@ -21,6 +22,8 @@
  
 static void SystemCheckTimer(bool * timer, uint64_t * last_timer, uint8_t step);
 static void SystemSetStackPattern(void);
+static void SystemEnableVBlankInterrupt(void);
+static void SystemDisableVBlankInterrupt(void);
 
 /* *************************************
  * 	Local Variables
@@ -41,16 +44,21 @@ static bool five_hundred_ms_timer;
 //Emergency mode flag. Toggled on pad connected/disconnected
 static bool emergency_mode;
 //Critical section is entered (i.e.: when accessing fopen() or other BIOS functions
-static bool system_busy;
+static volatile bool system_busy;
 //Timer array.
 static TYPE_TIMER timer_array[SYSTEM_MAX_TIMERS];
 
-/* *************************************
+/* *******************************************************************
+ * 
  * @name: void SystemInit(void)
- * @date: 19/05/2016
+ * 
  * @author: Xavier Del Campo
- * @brief:
- * *************************************/
+ * 
+ * @brief: Calls main intialization routines.
+ * 
+ * @remarks: To be called before main loop.
+ * 
+ * *******************************************************************/
 
 void SystemInit(void)
 {
@@ -97,6 +105,22 @@ void SystemInit(void)
 	StartRCnt(RCntCNT2);
 }
 
+/* *******************************************************************
+ * 
+ * @name: void SystemInit(void)
+ * 
+ * @author: Xavier Del Campo
+ * 
+ * @brief:
+ * 	Calls srand() while avoiding multiple calls by setting internal
+ *	variable rand_seed to true. Internal variable "global_timer" is
+ *	used to generate the new seed.
+ * 
+ * @remarks:
+ * 	It is recommended to call it once user has pressed any key.
+ * 
+ * *******************************************************************/
+
 void SystemSetRandSeed(void)
 {
 	if(rand_seed == false)
@@ -109,32 +133,81 @@ void SystemSetRandSeed(void)
 	}
 }
 
+/* *******************************************************************
+ * 
+ * @name: bool SystemIsRandSeedSet(void)
+ * 
+ * @author: Xavier Del Campo
+ * 
+ * @brief:
+ * 	Reportedly, returns whether rand seed has already been set.
+ * 
+ * @remarks:
+ *
+ * @return:
+ *	 Reportedly, returns whether rand seed has already been set.
+ * 
+ * *******************************************************************/
+
 bool SystemIsRandSeedSet(void)
 {
 	return rand_seed;
 }
 
-bool SystemDMAReady(void)
-{
-	return (*((unsigned int*)0x1F801814) & 1<<28);
-}
-
-bool SystemDMABusy(void)
-{
-	return !SystemDMAReady();
-}
+/* *******************************************************************
+ * 
+ * @name: bool SystemRefreshNeeded(void)
+ * 
+ * @author: Xavier Del Campo
+ * 
+ * @brief:
+ * 
+ * @remarks:
+ *
+ * @return:
+ *	 Returns whether VSync flag has been enabled.
+ * 
+ * *******************************************************************/
 
 bool SystemRefreshNeeded(void)
 {
 	return refresh_needed;
 }
 
+/* *******************************************************************
+ * 
+ * @name: void ISR_SystemDefaultVBlank(void)
+ * 
+ * @author: Xavier Del Campo
+ * 
+ * @brief:
+ * 
+ * @remarks:
+ * 	Called from VSync interrupt. Called 50 times a second in PAL mode,
+ * 	60 times a second in NTSC mode.
+ * 
+ * *******************************************************************/
+
 void ISR_SystemDefaultVBlank(void)
 {
 	refresh_needed = true;
 	SystemIncreaseGlobalTimer();
 }
 
+/* *******************************************************************
+ * 
+ * @name: void SystemIncreaseGlobalTimer(void)
+ * 
+ * @author: Xavier Del Campo
+ * 
+ * @brief:
+ * 	Increases internal variable responsible for time handling.
+ * 
+ * @remarks:
+ * 	Usually called from ISR_SystemDefaultVBlank().
+ * 
+ * *******************************************************************/
+
 void SystemIncreaseGlobalTimer(void)
 {
 	global_timer++;
@@ -201,6 +274,9 @@ bool SystemLoadFileToBuffer(char * fname, uint8_t * buffer, uint32_t szBuffer)
 	FILE *f;
 	int32_t size;
 	
+	// Wait for possible previous operation from the GPU before entering this section.
+	while( (SystemIsBusy() == true) || (GfxIsGPUBusy() == true) );
+	
 	if(fname == NULL)
 	{
 		dprintf("SystemLoadFile: NULL fname!\n");
@@ -210,6 +286,9 @@ bool SystemLoadFileToBuffer(char * fname, uint8_t * buffer, uint32_t szBuffer)
 	memset(buffer,0,szBuffer);
 	
 	system_busy = true;
+	
+	SystemDisableVBlankInterrupt();
+	
 	f = fopen(fname, "r");
 	
 	if(f == NULL)
@@ -219,7 +298,7 @@ bool SystemLoadFileToBuffer(char * fname, uint8_t * buffer, uint32_t szBuffer)
 		return false;
 	}
 
-	fseek(f, 0, SEEK_END);	
+	fseek(f, 0, SEEK_END);
 
 	size = ftell(f);
 	
@@ -236,6 +315,8 @@ bool SystemLoadFileToBuffer(char * fname, uint8_t * buffer, uint32_t szBuffer)
 	
 	fclose(f);
 	
+	SystemEnableVBlankInterrupt();
+	
 	system_busy = false;
 	
 	dprintf("File \"%s\" loaded successfully!\n",fname);
@@ -275,7 +356,7 @@ bool SystemGetEmergencyMode(void)
 	return emergency_mode;
 }
 
-bool SystemIsBusy(void)
+volatile bool SystemIsBusy(void)
 {
 	return system_busy;
 }
@@ -515,3 +596,35 @@ int32_t SystemIndexOf_U8(uint8_t value, uint8_t * array, uint32_t from, uint32_t
 	
 	return -1;
 }
+
+void SystemCyclicHandler(void)
+{
+	if(UpdatePads() == false)
+	{
+		SystemSetEmergencyMode(true);
+	}
+	else
+	{
+		SystemSetEmergencyMode(false);
+	}
+	
+	SystemRunTimers();
+	
+	SystemUserTimersHandler();
+	
+	SystemDisableScreenRefresh();
+	
+	MemCardHandler();
+	
+	SystemCheckStack();
+}
+
+void SystemDisableVBlankInterrupt(void)
+{
+	I_MASK &= ~(0x0001);
+}
+
+void SystemEnableVBlankInterrupt(void)
+{
+	I_MASK |= (0x0001);
+}
diff --git a/Source/System.h b/Source/System.h
index cbb22ea..b6ed48b 100644
--- a/Source/System.h
+++ b/Source/System.h
@@ -23,78 +23,108 @@
 
 // Calls PSXSDK init routines
 void SystemInit(void);
+
 // Sets default VSync (only sets flag to true and increases global_timer)
 void ISR_SystemDefaultVBlank(void);
+
 // Calls srand() using current global_timer value as seed
 void SystemSetRandSeed(void);
+
 // Returns VSync flag value
 bool SystemRefreshNeeded(void);
-// Tells whether CPU->GPU DMA transfer is ready
-bool SystemDMAReady(void);
-// Tells whether CPU->GPU DMA transfer is busy
-bool SystemDMABusy(void);
+
 // Loads a file into system's internal buffer
 bool SystemLoadFile(char *fname);
+
 // Loads a file into desired buffer
 bool SystemLoadFileToBuffer(char * fname, uint8_t * buffer, uint32_t szBuffer);
+
 // Clears VSync flag after each frame
 void SystemDisableScreenRefresh(void);
+
 // Returns file buffer address
 uint8_t * SystemGetBufferAddress(void);
+
 // Tells whether srand() has been called using a pseudo-random value
 bool SystemIsRandSeedSet(void);
+
 // Stops program flow during X cycles
 void SystemWaitCycles(uint32_t cycles);
+
 // To be called from GfxDrawScene after each cycle
 void SystemRunTimers(void);
+
 // 1 cycle-length flag with a frequency of 1 Hz
 bool System1SecondTick(void);
+
 // 1 cycle-length flag with a frequency of 2 Hz
 bool System500msTick(void);
+
 // 1 cycle-length flag with a frequency of 10 Hz
 bool System100msTick(void);
+
 // Returns random value between given minimum and maximum values
 uint32_t SystemRand(uint32_t min, uint32_t max);
+
 // Increases global timer by 1 step
 void SystemIncreaseGlobalTimer(void);
+
 // Sets value to emergency mode flag
 void SystemSetEmergencyMode(bool value);
+
 // Returns emergency mode flag state
 bool SystemGetEmergencyMode(void);
+
 // (Experimental)
 uint64_t SystemGetGlobalTimer(void);
+
 // Returns whether critical section of code is being entered
-bool SystemIsBusy(void);
+volatile bool SystemIsBusy(void);
+
 // Returns whether indicated value is contained inside buffer
 bool SystemContains_u8(uint8_t value, uint8_t * buffer, size_t sz);
+
 // Overload for uint16_t
 bool SystemContains_u16(uint16_t value, uint16_t * buffer, size_t sz);
+
 // Creates a timer instance wiht a determined value and associates it to a callback
 // Once time expires, callback is automatically called right after GfxDrawScene().
 TYPE_TIMER * SystemCreateTimer(uint32_t seconds, bool rf, void (*timer_callback)(void) );
+
 // Reportedly, sets all timer data to zero.
 void SystemResetTimers(void);
+
 // To be called every cycle (i.e.: inside GfxDrawScene() ).
 void SystemUserTimersHandler(void);
+
 // Sets timer remaining time to initial value.
 void SystemTimerRestart(TYPE_TIMER * timer);
+
 // Flushes a timer pointed to by timer.
 void SystemTimerRemove(TYPE_TIMER * timer);
+
 // Compares two arrays of unsigned short type.
 bool SystemArrayCompare(unsigned short * arr1, unsigned short * arr2, size_t sz);
+
 // Prints stack pointer address using dprintf()
 void SystemPrintStackPointerAddress(void);
+
 // Checks if a 32-bit pattern set at the end of the stack has been
 // accidentally modified by program flow.
 void SystemCheckStack(void);
+
 // Looks for string "str" inside a string array pointed to by "array".
 // Returns index inside string array on success, -1 if not found.
 int32_t SystemIndexOfStringArray(char * str, char ** array);
+
 // Function overload for uint16_t data type.
 int32_t SystemIndexOf_U16(uint16_t value, uint16_t * array, uint32_t sz);
+
 // Function overload for uint8_t data type.
 int32_t SystemIndexOf_U8(uint8_t value, uint8_t * array, uint32_t from, uint32_t sz);
 
+void SystemCyclicHandler(void);
+
 /* **************************************
  * 	Global Variables					*	
  * **************************************/