From be193088cac02d969b5ea2124fde76148b0480e9 Mon Sep 17 00:00:00 2001
From: Marcos Vitali <marcosvitali@gmail.com>
Date: Sun, 13 Feb 2011 15:08:37 +0000
Subject: [PATCH] - FIX RE0 GFX fifo errors :D - This game read the CPRead
 pointer when the GP is processing data and after detach the fifo  and attach
 again an use this pointer for continue, so implement fifo.SafeCPReadPointer
 pointer. - fifo.SafeCPReadPointer is updated when (FAKE_GetFifoEndPtr() -
 g_pVideoData) == 0) to have a pointer without GFX Commands Cut in the
 beginning of 32 block. - Reset video buffer when the CPReadWriteDistance is
 written by the software. - This commit is experimental please test a lot your
 games.

git-svn-id: https://dolphin-emu.googlecode.com/svn/trunk@7165 8ced0084-cf51-0410-be5f-012b33b47a6e
---
 Source/Core/Common/Src/VideoBackendBase.h       |  2 +-
 .../Core/VideoCommon/Src/CommandProcessor.cpp   | 17 +++++++++++++----
 Source/Core/VideoCommon/Src/Fifo.cpp            |  3 ++-
 3 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/Source/Core/Common/Src/VideoBackendBase.h b/Source/Core/Common/Src/VideoBackendBase.h
index 798750ca73..3e9c71bfb9 100644
--- a/Source/Core/Common/Src/VideoBackendBase.h
+++ b/Source/Core/Common/Src/VideoBackendBase.h
@@ -49,7 +49,7 @@ struct SCPFifoStruct
 	volatile u32 CPWritePointer;
 	volatile u32 CPReadPointer;
 	volatile u32 CPBreakpoint;
-
+	volatile u32 SafeCPReadPointer;
 	// Super Monkey Ball Adventure require this.
 	// Because the read&check-PEToken-loop stays in its JITed block I suppose.
 	// So no possiblity to ack the Token irq by the scheduler until some sort of PPC watchdog do its mess.
diff --git a/Source/Core/VideoCommon/Src/CommandProcessor.cpp b/Source/Core/VideoCommon/Src/CommandProcessor.cpp
index a8ee3c8df6..05ebd1ede2 100644
--- a/Source/Core/VideoCommon/Src/CommandProcessor.cpp
+++ b/Source/Core/VideoCommon/Src/CommandProcessor.cpp
@@ -284,13 +284,19 @@ void Read16(u16& _rReturnValue, const u32 _Address)
 		return;
 
 	case FIFO_READ_POINTER_LO:
-		_rReturnValue = ReadLow (fifo.CPReadPointer);
+		if (IsOnThread())
+			_rReturnValue = ReadLow (fifo.SafeCPReadPointer);
+		else
+			_rReturnValue = ReadLow (fifo.CPReadPointer);
 		// hack: CPU will always believe fifo is empty and on idle
 		//_rReturnValue = ReadLow (fifo.CPWritePointer);
 		DEBUG_LOG(COMMANDPROCESSOR, "read FIFO_READ_POINTER_LO : %04x", _rReturnValue);
 		return;
 	case FIFO_READ_POINTER_HI:
-		_rReturnValue = ReadHigh(fifo.CPReadPointer);
+		if (IsOnThread())
+			_rReturnValue = ReadHigh (fifo.SafeCPReadPointer);
+		else
+			_rReturnValue = ReadHigh (fifo.CPReadPointer);
 		// hack: CPU will always believe fifo is empty and on idle
 	    //_rReturnValue = ReadHigh(fifo.CPWritePointer);
 		DEBUG_LOG(COMMANDPROCESSOR, "read FIFO_READ_POINTER_HI : %04x", _rReturnValue);
@@ -614,8 +620,11 @@ void Write16(const u16 _Value, const u32 _Address)
 		{
 			GPFifo::ResetGatherPipe();
 			ResetVideoBuffer();
-			IncrementCheckContextId();
-		}		
+		}else
+		{
+			ResetVideoBuffer();		
+		}
+		IncrementCheckContextId();
 		DEBUG_LOG(COMMANDPROCESSOR,"try to write to FIFO_RW_DISTANCE_LO : %04x", _Value);
 		break;
 
diff --git a/Source/Core/VideoCommon/Src/Fifo.cpp b/Source/Core/VideoCommon/Src/Fifo.cpp
index 18daeec5b7..f459fd4ef6 100644
--- a/Source/Core/VideoCommon/Src/Fifo.cpp
+++ b/Source/Core/VideoCommon/Src/Fifo.cpp
@@ -169,7 +169,8 @@ void Fifo_EnterLoop()
 
 			Common::AtomicStore(_fifo.CPReadPointer, readPtr);
 			Common::AtomicAdd(_fifo.CPReadWriteDistance, -distToSend);						
-		    			
+			if((FAKE_GetFifoEndPtr() - g_pVideoData) == 0)
+				Common::AtomicStore(_fifo.SafeCPReadPointer, _fifo.CPReadPointer);
 			CommandProcessor::SetStatus();
 		
 			// This call is pretty important in DualCore mode and must be called in the FIFO Loop.