diff --git a/src/nvcore/Prefetch.h b/src/nvcore/Prefetch.h
index aa0bcfc..71bd0ed 100644
--- a/src/nvcore/Prefetch.h
+++ b/src/nvcore/Prefetch.h
@@ -24,7 +24,7 @@ __forceinline void nvPrefetch(const void * mem)
 #else // NV_CC_MSVC
 
 // do nothing in other case.
-#define piPrefetch(ptr)
+#define nvPrefetch(ptr)
 
 #endif // NV_CC_MSVC
 
diff --git a/src/nvcore/Ptr.h b/src/nvcore/Ptr.h
index 4b35718..b5e9fe7 100644
--- a/src/nvcore/Ptr.h
+++ b/src/nvcore/Ptr.h
@@ -48,8 +48,11 @@ public:
 
 	/** Delete owned pointer and assign new one. */
 	void operator=( T * p ) {
-		delete m_ptr;
-		m_ptr = p;
+		if (p != m_ptr)
+		{
+			delete m_ptr;
+			m_ptr = p;
+		}
 	}
 
 	/** Member access. */
diff --git a/src/nvcore/ThreadLocalStorage.h b/src/nvcore/ThreadLocalStorage.h
new file mode 100755
index 0000000..f71a07d
--- /dev/null
+++ b/src/nvcore/ThreadLocalStorage.h
@@ -0,0 +1,73 @@
+// This code is in the public domain -- castanyo@yahoo.es
+
+#ifndef NV_CORE_THREADLOCALSTORAGE_H
+#define NV_CORE_THREADLOCALSTORAGE_H
+
+#include <nvcore/nvcore.h>
+
+// ThreadLocal<Context> context;
+//
+// context.allocate();
+//
+//   context = new Context();
+//   context->member();
+//   context = NULL;
+//
+// context.free();
+
+#if NV_CC_GNUC
+
+#elif NV_CC_MSVC 
+
+template <class T>
+class ThreadLocal
+{
+public:
+	ThreadLocal() : index(0) {}
+	~ThreadLocal() { nvCheck(index == 0); }
+	
+	void allocate()
+	{
+		index = TlsAlloc();
+	}
+	void free()
+	{
+		delete ptr();
+		TlsFree(index);
+		index = 0;
+	}
+	bool isValid()
+	{
+		return index != 0;
+	}
+	
+	void operator=( T * p )
+	{
+		if (p != ptr())
+		{
+			delete ptr();
+			TlsSetValue(index, p);
+		}
+	}
+	
+	T * operator -> () const
+	{
+		return ptr();
+	}
+	
+	T & operator*() const
+	{
+		return *ptr();
+	}
+	
+	T * ptr() const { 
+		return static_cast<T *>(TlsGetValue(index));
+	}
+	
+	DWORD index;
+};
+
+
+#endif // NV_CC_MSVC
+
+#endif // NV_CORE_THREADLOCALSTORAGE_H