diff --git a/de4dot.blocks/cflow/InstructionEmulator.cs b/de4dot.blocks/cflow/InstructionEmulator.cs
index 56f6a47f..0eab99ee 100644
--- a/de4dot.blocks/cflow/InstructionEmulator.cs
+++ b/de4dot.blocks/cflow/InstructionEmulator.cs
@@ -141,7 +141,7 @@ namespace de4dot.blocks.cflow {
 
 			case ElementType.R4:
 				if (value.IsReal8())
-					return new Real8Value((float)((Real8Value)value).Value);
+					return ((Real8Value)value).ToSingle();
 				return new UnknownValue();
 
 			case ElementType.R8:
@@ -870,6 +870,8 @@ namespace de4dot.blocks.cflow {
 				valueStack.Push(Int32Value.Add_Ovf((Int32Value)val1, (Int32Value)val2));
 			else if (val1.IsInt64() && val2.IsInt64())
 				valueStack.Push(Int64Value.Add_Ovf((Int64Value)val1, (Int64Value)val2));
+			else if (val1.IsReal8() && val2.IsReal8())
+				valueStack.Push(Real8Value.Add_Ovf((Real8Value)val1, (Real8Value)val2));
 			else
 				valueStack.PushUnknown();
 		}
@@ -882,6 +884,8 @@ namespace de4dot.blocks.cflow {
 				valueStack.Push(Int32Value.Add_Ovf_Un((Int32Value)val1, (Int32Value)val2));
 			else if (val1.IsInt64() && val2.IsInt64())
 				valueStack.Push(Int64Value.Add_Ovf_Un((Int64Value)val1, (Int64Value)val2));
+			else if (val1.IsReal8() && val2.IsReal8())
+				valueStack.Push(Real8Value.Add_Ovf_Un((Real8Value)val1, (Real8Value)val2));
 			else
 				valueStack.PushUnknown();
 		}
@@ -894,6 +898,8 @@ namespace de4dot.blocks.cflow {
 				valueStack.Push(Int32Value.Sub_Ovf((Int32Value)val1, (Int32Value)val2));
 			else if (val1.IsInt64() && val2.IsInt64())
 				valueStack.Push(Int64Value.Sub_Ovf((Int64Value)val1, (Int64Value)val2));
+			else if (val1.IsReal8() && val2.IsReal8())
+				valueStack.Push(Real8Value.Sub_Ovf((Real8Value)val1, (Real8Value)val2));
 			else
 				valueStack.PushUnknown();
 		}
@@ -906,6 +912,8 @@ namespace de4dot.blocks.cflow {
 				valueStack.Push(Int32Value.Sub_Ovf_Un((Int32Value)val1, (Int32Value)val2));
 			else if (val1.IsInt64() && val2.IsInt64())
 				valueStack.Push(Int64Value.Sub_Ovf_Un((Int64Value)val1, (Int64Value)val2));
+			else if (val1.IsReal8() && val2.IsReal8())
+				valueStack.Push(Real8Value.Sub_Ovf_Un((Real8Value)val1, (Real8Value)val2));
 			else
 				valueStack.PushUnknown();
 		}
@@ -918,6 +926,8 @@ namespace de4dot.blocks.cflow {
 				valueStack.Push(Int32Value.Mul_Ovf((Int32Value)val1, (Int32Value)val2));
 			else if (val1.IsInt64() && val2.IsInt64())
 				valueStack.Push(Int64Value.Mul_Ovf((Int64Value)val1, (Int64Value)val2));
+			else if (val1.IsReal8() && val2.IsReal8())
+				valueStack.Push(Real8Value.Mul_Ovf((Real8Value)val1, (Real8Value)val2));
 			else
 				valueStack.PushUnknown();
 		}
@@ -930,6 +940,8 @@ namespace de4dot.blocks.cflow {
 				valueStack.Push(Int32Value.Mul_Ovf_Un((Int32Value)val1, (Int32Value)val2));
 			else if (val1.IsInt64() && val2.IsInt64())
 				valueStack.Push(Int64Value.Mul_Ovf_Un((Int64Value)val1, (Int64Value)val2));
+			else if (val1.IsReal8() && val2.IsReal8())
+				valueStack.Push(Real8Value.Mul_Ovf_Un((Real8Value)val1, (Real8Value)val2));
 			else
 				valueStack.PushUnknown();
 		}
diff --git a/de4dot.blocks/cflow/Int32Value.cs b/de4dot.blocks/cflow/Int32Value.cs
index 41844f33..85c9b544 100644
--- a/de4dot.blocks/cflow/Int32Value.cs
+++ b/de4dot.blocks/cflow/Int32Value.cs
@@ -131,6 +131,8 @@ namespace de4dot.blocks.cflow {
 		}
 
 		public static Int32Value Conv_U1(Real8Value a) {
+			if (!a.IsValid)
+				return CreateUnknownUInt8();
 			return new Int32Value((int)(byte)a.Value);
 		}
 
@@ -152,6 +154,8 @@ namespace de4dot.blocks.cflow {
 		}
 
 		public static Int32Value Conv_I1(Real8Value a) {
+			if (!a.IsValid)
+				return CreateUnknown();
 			return new Int32Value((int)(sbyte)a.Value);
 		}
 
@@ -170,6 +174,8 @@ namespace de4dot.blocks.cflow {
 		}
 
 		public static Int32Value Conv_U2(Real8Value a) {
+			if (!a.IsValid)
+				return CreateUnknownUInt16();
 			return new Int32Value((int)(ushort)a.Value);
 		}
 
@@ -191,6 +197,8 @@ namespace de4dot.blocks.cflow {
 		}
 
 		public static Int32Value Conv_I2(Real8Value a) {
+			if (!a.IsValid)
+				return CreateUnknown();
 			return new Int32Value((int)(short)a.Value);
 		}
 
@@ -203,6 +211,8 @@ namespace de4dot.blocks.cflow {
 		}
 
 		public static Int32Value Conv_U4(Real8Value a) {
+			if (!a.IsValid)
+				return CreateUnknown();
 			return new Int32Value((int)(uint)a.Value);
 		}
 
@@ -215,6 +225,8 @@ namespace de4dot.blocks.cflow {
 		}
 
 		public static Int32Value Conv_I4(Real8Value a) {
+			if (!a.IsValid)
+				return CreateUnknown();
 			return new Int32Value((int)a.Value);
 		}
 
diff --git a/de4dot.blocks/cflow/Int64Value.cs b/de4dot.blocks/cflow/Int64Value.cs
index 0bf4a558..48a236e3 100644
--- a/de4dot.blocks/cflow/Int64Value.cs
+++ b/de4dot.blocks/cflow/Int64Value.cs
@@ -91,6 +91,8 @@ namespace de4dot.blocks.cflow {
 		}
 
 		public static Int64Value Conv_U8(Real8Value a) {
+			if (!a.IsValid)
+				return CreateUnknown();
 			return new Int64Value((long)(ulong)a.Value);
 		}
 
@@ -109,6 +111,8 @@ namespace de4dot.blocks.cflow {
 		}
 
 		public static Int64Value Conv_I8(Real8Value a) {
+			if (!a.IsValid)
+				return CreateUnknown();
 			return new Int64Value((long)a.Value);
 		}
 
diff --git a/de4dot.blocks/cflow/Real8Value.cs b/de4dot.blocks/cflow/Real8Value.cs
index 511fcbaf..d6c7bbd8 100644
--- a/de4dot.blocks/cflow/Real8Value.cs
+++ b/de4dot.blocks/cflow/Real8Value.cs
@@ -20,36 +20,90 @@
 namespace de4dot.blocks.cflow {
 	public class Real8Value : Value {
 		public readonly double Value;
+		public readonly bool IsValid;
 
 		public Real8Value(double value)
 			: base(ValueType.Real8) {
 			this.Value = value;
+			this.IsValid = true;
+		}
+
+		public Real8Value(double value, bool isValid)
+			: base(ValueType.Real8) {
+			this.Value = value;
+			this.IsValid = isValid;
+		}
+
+		public static Real8Value CreateUnknown() {
+			return new Real8Value(0, false);
+		}
+
+		public Real8Value ToSingle() {
+			if (!IsValid)
+				return CreateUnknown();
+			return new Real8Value((float)Value);
 		}
 
 		public static Real8Value Add(Real8Value a, Real8Value b) {
+			if (!a.IsValid || !b.IsValid)
+				return CreateUnknown();
 			return new Real8Value(a.Value + b.Value);
 		}
 
 		public static Real8Value Sub(Real8Value a, Real8Value b) {
+			if (!a.IsValid || !b.IsValid)
+				return CreateUnknown();
 			return new Real8Value(a.Value - b.Value);
 		}
 
 		public static Real8Value Mul(Real8Value a, Real8Value b) {
+			if (!a.IsValid || !b.IsValid)
+				return CreateUnknown();
 			return new Real8Value(a.Value * b.Value);
 		}
 
 		public static Real8Value Div(Real8Value a, Real8Value b) {
+			if (!a.IsValid || !b.IsValid)
+				return CreateUnknown();
 			return new Real8Value(a.Value / b.Value);
 		}
 
 		public static Real8Value Rem(Real8Value a, Real8Value b) {
+			if (!a.IsValid || !b.IsValid)
+				return CreateUnknown();
 			return new Real8Value(a.Value % b.Value);
 		}
 
 		public static Real8Value Neg(Real8Value a) {
+			if (!a.IsValid)
+				return CreateUnknown();
 			return new Real8Value(-a.Value);
 		}
 
+		public static Real8Value Add_Ovf(Real8Value a, Real8Value b) {
+			return CreateUnknown();
+		}
+
+		public static Real8Value Add_Ovf_Un(Real8Value a, Real8Value b) {
+			return CreateUnknown();
+		}
+
+		public static Real8Value Sub_Ovf(Real8Value a, Real8Value b) {
+			return CreateUnknown();
+		}
+
+		public static Real8Value Sub_Ovf_Un(Real8Value a, Real8Value b) {
+			return CreateUnknown();
+		}
+
+		public static Real8Value Mul_Ovf(Real8Value a, Real8Value b) {
+			return CreateUnknown();
+		}
+
+		public static Real8Value Mul_Ovf_Un(Real8Value a, Real8Value b) {
+			return CreateUnknown();
+		}
+
 		public static Int32Value Conv_Ovf_I1(Real8Value a) {
 			return Int32Value.CreateUnknown();
 		}