From cec7963a9d97a95d4fc856897455a0132d41345d Mon Sep 17 00:00:00 2001
From: Angelo Papenhoff <angelo.papenhoff@gmail.com>
Date: Tue, 30 Dec 2014 19:30:13 +0100
Subject: [PATCH] Added functions for fixing/unfixing DMA pointers in PS2 data.

---
 src/ps2.cpp | 86 +++++++++++++++++++++++++++++++++++++++++++++++++++--
 src/rwps2.h | 10 ++++++-
 2 files changed, 92 insertions(+), 4 deletions(-)

diff --git a/src/ps2.cpp b/src/ps2.cpp
index 753d9e4..576de52 100644
--- a/src/ps2.cpp
+++ b/src/ps2.cpp
@@ -45,11 +45,13 @@ ReadNativeData(Stream *stream, int32, void *object, int32, int32)
 		uint32 buf[2];
 		stream->read(buf, 8);
 		instance->dataSize = buf[0];
-		instance->noRefChain = buf[1];
+		instance->arePointersFixed = buf[1];
 // TODO: force alignment
 		instance->data = new uint8[instance->dataSize];
-		uint64 a = (uint64)instance->data ;
+#ifdef RW_PS2
+		uint32 a = (uint32)instance->data;
 		assert(a % 0x10 == 0);
+#endif
 		stream->read(instance->data, instance->dataSize);
 	}
 }
@@ -65,9 +67,11 @@ WriteNativeData(Stream *stream, int32 len, void *object, int32, int32)
 	InstanceDataHeader *header = (InstanceDataHeader*)geometry->instData;
 	for(uint32 i = 0; i < header->numMeshes; i++){
 		InstanceData *instance = &header->instanceMeshes[i];
+		if(instance->arePointersFixed == 2)
+			unfixDmaOffsets(instance);
 		uint32 buf[2];
 		buf[0] = instance->dataSize;
-		buf[1] = instance->noRefChain;
+		buf[1] = instance->arePointersFixed;
 		stream->write(buf, 8);
 		stream->write(instance->data, instance->dataSize);
 	}
@@ -100,5 +104,81 @@ registerNativeDataPlugin(void)
 	                               (StreamGetSize)GetSizeNativeData);
 }
 
+#ifdef RW_PS2
+void
+fixDmaOffsets(InstanceData *inst)
+{
+	if(inst->arePointersFixed)
+		return;
+
+	uint32 base = (uint32)inst->data;
+	uint32 *tag = (uint32*)inst->data;
+	for(;;){
+		switch(tag[0]&0x70000000){
+		// DMAcnt
+		case 0x10000000:
+			// no need to fix
+			tag += (1+(tag[0]&0xFFFF))*4;
+			break;
+
+		// DMAref
+		case 0x30000000:
+			// fix address and jump to next
+			tag[1] = base + tag[1]*0x10;
+			tag += 4;
+			break;
+
+		// DMAret
+		case 0x60000000:
+			// we're done
+			inst->arePointersFixed = 2;
+			return;
+
+		default:
+			fprintf(stderr, "error: unknown DMAtag %X\n", tag[0]);
+			return;
+		}
+	}
+}
+#endif
+
+void
+unfixDmaOffsets(InstanceData *inst)
+{
+#ifdef RW_PS2
+	if(inst->arePointersFixed != 2)
+		return;
+
+	uint32 base = (uint32)inst->data;
+	uint32 *tag = (uint32*)inst->data;
+	for(;;){
+		switch(tag[0]&0x70000000){
+		// DMAcnt
+		case 0x10000000:
+			// no need to unfix
+			tag += (1+(tag[0]&0xFFFF))*4;
+			break;
+
+		// DMAref
+		case 0x30000000:
+			// unfix address and jump to next
+			tag[1] = (tag[1] - base)/0x10;
+			tag += 4;
+			break;
+
+		// DMAret
+		case 0x60000000:
+			// we're done
+			inst->arePointersFixed = 0;
+			return;
+
+		default:
+			fprintf(stderr, "error: unknown DMAtag %X\n", tag[0]);
+			return;
+		}
+	}
+#endif
+}
+
 }
 }
diff --git a/src/rwps2.h b/src/rwps2.h
index 5fa41b4..81d50e8 100644
--- a/src/rwps2.h
+++ b/src/rwps2.h
@@ -3,7 +3,11 @@ namespace Ps2 {
 
 struct InstanceData
 {
-	uint32 noRefChain;
+	// 0 - addresses in ref tags need fixing
+	// 1 - no ref tags, so no fixing
+	// set by the program:
+	// 2 - ref tags are fixed, need to unfix before stream write
+	uint32 arePointersFixed;
 	uint32 dataSize;
 	uint8 *data;
 	Material *material;
@@ -21,5 +25,9 @@ void WriteNativeData(Stream *stream, int32 len, void *object, int32, int32);
 int32 GetSizeNativeData(void *object, int32, int32);
 void registerNativeDataPlugin(void);
 
+// only RW_PS2
+void fixDmaOffsets(InstanceData *inst);
+void unfixDmaOffsets(InstanceData *inst);
+
 }
 }