diff --git a/blocks/cflow/InstructionEmulator.cs b/blocks/cflow/InstructionEmulator.cs
index 786f5b09..18ce2bae 100644
--- a/blocks/cflow/InstructionEmulator.cs
+++ b/blocks/cflow/InstructionEmulator.cs
@@ -26,6 +26,7 @@ using Mono.Cecil.Metadata;
 namespace de4dot.blocks.cflow {
 	public class InstructionEmulator {
 		ValueStack valueStack = new ValueStack();
+		Dictionary<Value, bool> protectedStackValues = new Dictionary<Value, bool>();
 		IList<ParameterDefinition> parameterDefinitions;
 		IList<VariableDefinition> variableDefinitions;
 		List<Value> args = new List<Value>();
@@ -52,6 +53,7 @@ namespace de4dot.blocks.cflow {
 			this.parameterDefinitions = method.Parameters;
 			this.variableDefinitions = method.Body.Variables;
 			valueStack.init();
+			protectedStackValues.Clear();
 
 			if (method != prev_method) {
 				prev_method = method;
@@ -77,6 +79,10 @@ namespace de4dot.blocks.cflow {
 			locals.AddRange(cached_locals);
 		}
 
+		public void setProtected(Value value) {
+			protectedStackValues[value] = true;
+		}
+
 		static Value getUnknownValue(TypeReference typeReference) {
 			if (typeReference == null)
 				return new UnknownValue();
@@ -94,9 +100,11 @@ namespace de4dot.blocks.cflow {
 			return new UnknownValue();
 		}
 
-		static Value truncateValue(Value value, TypeReference typeReference) {
+		Value truncateValue(Value value, TypeReference typeReference) {
 			if (typeReference == null)
 				return value;
+			if (protectedStackValues.ContainsKey(value))
+				return value;
 
 			switch (typeReference.EType) {
 			case ElementType.Boolean:
@@ -208,6 +216,10 @@ namespace de4dot.blocks.cflow {
 			return new UnknownValue();
 		}
 
+		public int stackSize() {
+			return valueStack.Size;
+		}
+
 		public void push(Value value) {
 			valueStack.push(value);
 		}
diff --git a/blocks/cflow/ValueStack.cs b/blocks/cflow/ValueStack.cs
index e9528fd5..7d26d67e 100644
--- a/blocks/cflow/ValueStack.cs
+++ b/blocks/cflow/ValueStack.cs
@@ -25,6 +25,10 @@ namespace de4dot.blocks.cflow {
 	class ValueStack {
 		List<Value> stack = new List<Value>();
 
+		public int Size {
+			get { return stack.Count; }
+		}
+
 		public void init() {
 			stack.Clear();
 		}