From f30aebf8d7bac892d08ef5585c2e858cf6d3f50b Mon Sep 17 00:00:00 2001
From: skidau <skidau@gmail.com>
Date: Sun, 25 Mar 2012 21:35:57 +1100
Subject: [PATCH] Added a check for TMEM overflows while preloading textures. 
 Thanks to NeoBrainX for the tip.

---
 Source/Core/VideoCommon/Src/BPMemory.h    |  2 +-
 Source/Core/VideoCommon/Src/BPStructs.cpp | 20 +++++++++++---------
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/Source/Core/VideoCommon/Src/BPMemory.h b/Source/Core/VideoCommon/Src/BPMemory.h
index 0bb2bf9013..de5c616f0f 100644
--- a/Source/Core/VideoCommon/Src/BPMemory.h
+++ b/Source/Core/VideoCommon/Src/BPMemory.h
@@ -62,7 +62,7 @@
 #define BPMEM_COPYFILTER1      0x54
 #define BPMEM_CLEARBBOX1       0x55 
 #define BPMEM_CLEARBBOX2       0x56
-#define BPMEM_UNKOWN_57        0x57
+#define BPMEM_UNKNOWN_57       0x57
 #define BPMEM_REVBITS          0x58
 #define BPMEM_SCISSOROFFSET    0x59
 #define BPMEM_PRELOAD_ADDR     0x60
diff --git a/Source/Core/VideoCommon/Src/BPStructs.cpp b/Source/Core/VideoCommon/Src/BPStructs.cpp
index 01b09e351b..d59523e117 100644
--- a/Source/Core/VideoCommon/Src/BPStructs.cpp
+++ b/Source/Core/VideoCommon/Src/BPStructs.cpp
@@ -463,8 +463,8 @@ void BPWritten(const BPCmd& bp)
 	case BPMEM_REVBITS: // Always set to 0x0F when GX_InitRevBits() is called.
 		break;
 
-	case BPMEM_UNKOWN_57: // Sunshine alternates this register between values 0x000 and 0xAAA
-		DEBUG_LOG(VIDEO, "Uknown BP Reg 0x57: %08x", bp.newvalue);
+	case BPMEM_UNKNOWN_57: // Sunshine alternates this register between values 0x000 and 0xAAA
+		DEBUG_LOG(VIDEO, "Unknown BP Reg 0x57: %08x", bp.newvalue);
 		break;
 
 	case BPMEM_PRELOAD_ADDR:
@@ -476,16 +476,18 @@ void BPWritten(const BPCmd& bp)
 		// if this is different from 0, manual TMEM management is used.
 		if (bp.newvalue != 0)
 		{
+			// NOTE(neobrain): Apparently tmemodd doesn't affect hardware behavior at all (libogc uses it just as a buffer and switches its contents with tmemeven whenever this is called)
 			BPS_TmemConfig& tmem_cfg = bpmem.tmem_config;
 			u8* ram_ptr = Memory::GetPointer(tmem_cfg.preload_addr << 5);
-			u32 tmem_addr = 0;
-
-			if (bp.newvalue >> 16)
-				tmem_addr = tmem_cfg.preload_tmem_odd * TMEM_LINE_SIZE;
-			else
-				tmem_addr = tmem_cfg.preload_tmem_even * TMEM_LINE_SIZE;
-
+			u32 tmem_addr = tmem_cfg.preload_tmem_even * TMEM_LINE_SIZE;
 			u32 size = tmem_cfg.preload_tile_info.count * 32;
+
+			// Check if the game has overflowed TMEM, and copy up to the limit.
+			// Paper Mario does this when entering the Great Boogly Tree (Chap 2)
+			// TODO: Does this wrap?
+			if ((tmem_addr + size) > TMEM_SIZE)
+				size = TMEM_SIZE - tmem_addr;
+
 			memcpy(texMem + tmem_addr, ram_ptr, size);
 		}
 		break;