diff --git a/dub.sdl b/dub.sdl
index 2c95751..43c4538 100644
--- a/dub.sdl
+++ b/dub.sdl
@@ -9,6 +9,7 @@ sourcePaths
 configuration "clox" {
 	buildOptions "betterC"
 	sourcePaths "src/clox"
+	versions "nanBoxing"
 }
 
 configuration "clox-dbg" {
@@ -18,6 +19,8 @@ configuration "clox-dbg" {
 	sourcePaths "src/clox"
 	buildRequirements "requireBoundsCheck" "requireContracts"
 
+	versions "nanBoxing"
+
 	debugVersions "printCode" "traceExec"
 
 	/* debugVersions "stressGC" */
diff --git a/src/clox/container/table.d b/src/clox/container/table.d
index c989dcb..2add2e5 100644
--- a/src/clox/container/table.d
+++ b/src/clox/container/table.d
@@ -8,6 +8,7 @@ debug import std.stdio : writeln;
 import clox.memory;
 import clox.memorydbg;
 import clox.obj;
+import clox.util;
 import clox.value;
 import clox.container.dynarray;
 import conf = clox.conf;
@@ -29,6 +30,7 @@ struct Table(K, V){
 	Entry[] pool;
 	size_t alive;
 	this(size_t size){
+		size = npow2(size);
 		pool = allocatePool(size);
 	}
 	void free(){
@@ -69,21 +71,21 @@ struct Table(K, V){
 		if(alive == 0)
 			return null;
 		Hash hash = getHash(key);
-		size_t index = hash % pool.length;
+		size_t index = hash & ((pool.length) - 1);
 		while(true){
 			const entry = pool[index];
 			if(entry.isAlive && entry.key == key)
 				return &pool[index];
 			if(entry.isFree)
 				break;
-			index = (index+1) % pool.length;
+			index = (index+1) & ((pool.length) - 1);
 		}
 		return null;
 	}
 	void opIndexAssign(V val, in K key){
 		checkResize();
 		Hash hash = getHash(key);
-		size_t index = hash % pool.length;
+		size_t index = hash & ((pool.length) - 1);
 		while(true){
 			const Entry* entry = &pool[index];
 			if(entry.isAlive && entry.key == key)
@@ -92,7 +94,7 @@ struct Table(K, V){
 				alive++;
 				break;
 			}
-			index = (index+1) % pool.length;
+			index = (index+1) & ((pool.length) - 1);
 		}
 		pool[index] = Entry(cast(K)key, val);
 	}
diff --git a/src/clox/util.d b/src/clox/util.d
index c8acdb4..ad2d5fd 100644
--- a/src/clox/util.d
+++ b/src/clox/util.d
@@ -70,3 +70,18 @@ version(D_BetterC) {} else string prettyPtr(void* ptr){
 	return "\033[38;2;" ~ colours[0].to!string ~ ";" ~ colours[1].to!string ~ ";" ~ colours[2].to!string ~ "m" ~ ptr.to!string ~ "\033[0m";
 }
 
+size_t npow2(size_t n){
+	n--;
+	n |= n >> 1;
+	n |= n >> 2;
+	n |= n >> 4;
+	n |= n >> 8;
+	n |= n >> 16;
+	return n + 1;
+}
+
+// https://github.com/dlang/phobos/blob/832cc465998b1ea77051cd3fd014b544442a4f8c/std/conv.d#L6396
+pragma(inline, true) ref T bitCast(T, S)(ref S value) if (T.sizeof <= S.sizeof){
+	return *cast(T*) &value;
+}
+
diff --git a/src/clox/value.d b/src/clox/value.d
index 5a079f9..4b66f2a 100644
--- a/src/clox/value.d
+++ b/src/clox/value.d
@@ -4,41 +4,88 @@ import core.stdc.stdio;
 
 import clox.memory;
 import clox.obj;
+import clox.util;
 
 struct Value{
 	enum Type{
 		None, Bool, Nil, Number, Obj
 	}
-	Type type;
-	private union Un{
-		bool boolean;
-		double number;
-		Obj* obj;
-	}
-	private Un un;
+	version(nanBoxing){
+		private enum QNAN = ulong(0x7ffc000000000000);
+		private enum SIGN_BIT = ulong(0x8000000000000000);
+		enum Tag{
+			Nil = 1, False = 2, True = 3
+		}
+		ulong data;
+		static Value from(double val) => Value(val.bitCast!ulong);
+		static Value from(bool val) => Value(val ? QNAN | Tag.True : QNAN | Tag.False);
+		static Value from(T)(T* val) if(__traits(compiles, val.obj)) => Value(SIGN_BIT | QNAN | val.bitCast!ulong);
+		static Value nil() pure => Value(QNAN | Tag.Nil);
+
+		Type type() const pure{
+			if(isType(Type.Number))
+				return Type.Number;
+			if(isType(Type.Bool))
+				return Type.Bool;
+			if(isType(Type.Nil))
+				return Type.Nil;
+			if(isType(Type.Obj))
+				return Type.Obj;
+			assert(0);
+		}
+
+		bool isType(Type type) const pure{
+			final switch(type){
+				case Type.Number: return (data & QNAN) != QNAN;
+				case Type.Nil: return data == nil.data;
+				case Type.Bool: return data == (QNAN | Tag.True) || data == (QNAN | Tag.False);
+				case Type.Obj: return (data & (QNAN | SIGN_BIT)) == (QNAN | SIGN_BIT);
+				case Type.None: assert(0);
+			}
+		}
+
+		auto as(Type type)() const pure{
+			static if(type != Type.None)
+				assert(isType(type));
+			static if(type == Type.Number) return data.bitCast!double;
+			static if(type == Type.Bool) return data == (QNAN | Tag.True);
+			static if(type == Type.Obj) return cast(Obj*)(data & ~(SIGN_BIT | QNAN));
+			static if(type == Type.None) return this;
+		}
+
+	} else {
+		private union Un{
+			bool boolean;
+			double number;
+			Obj* obj;
+		}
+		private Type type;
+		private Un un;
+		static Value from(double val) => Value(Type.Number, Un(number: val));
+		static Value from(bool val)   => Value(Type.Bool, Un(boolean: val));
+		static Value from(T)(T* val) if(__traits(compiles, val.obj)) => Value(Type.Obj, Un(obj: cast(Obj*)val));
+		static Value from(Value val)  => val;
+		static Value nil() pure => Value(Type.Nil);
+
+		bool isType(Type type) const pure => this.type == type;
+		auto as(Type type)() const pure{
+			static if(type != Type.None)
+				assert(isType(type));
+			static if(type == Type.Number) return un.number;
+			static if(type == Type.Bool) return un.boolean;
+			static if(type == Type.Obj) return un.obj;
+			static if(type == Type.None) return this;
+		}
 
-	bool isType(Type type)        const pure => this.type == type;
-	bool isType(Obj.Type type) const pure => this.type == Type.Obj && asObj.isType(type);
-	auto as(Type type)() const pure{
-		static if(type != Type.None)
-			assert(this.type == type);
-		static if(type == Type.Number) return un.number;
-		static if(type == Type.Bool) return un.boolean;
-		static if(type == Type.Obj) return un.obj;
-		static if(type == Type.None) return this;
 	}
 
+	bool isType(Obj.Type type) const pure => isType(Type.Obj) && asObj.isType(type);
+
 	bool   asBoolean() const pure => as!(Type.Bool);
 	double asNumber()  const pure => as!(Type.Number);
 	Obj*   asObj()     const pure => cast(Obj*)as!(Type.Obj);
 
-	static Value from(T: double)(T val) => Value(Type.Number, Un(number: val));
-	static Value from(T: bool)(T val)   => Value(Type.Bool, Un(boolean: val));
-	static Value from(T)(T* val) if(__traits(compiles, val.obj)) => Value(Type.Obj, Un(obj: cast(Obj*)val));
-	static Value from(T: Value)(T val)  => val;
-	static Value nil() pure => Value(Type.Nil);
-
-	bool isFalsey() const pure => (type == Type.Bool && asBoolean == false) || type == Type.Nil;
+	bool isFalsey() const pure => (isType(Type.Bool) && asBoolean == false) || isType(Type.Nil);
 	bool isTruthy() const pure => !isFalsey;
 	bool opEquals(Value rhs) const pure{
 		if(rhs.type != type)
diff --git a/src/clox/vm.d b/src/clox/vm.d
index 10122da..2097031 100644
--- a/src/clox/vm.d
+++ b/src/clox/vm.d
@@ -108,7 +108,6 @@ struct VM{
 		Value readConstant() => chunk.constants[readVarUint()];
 		Obj.String* readString() => readConstant().asObj.asString;
 		bool checkBinaryType(alias type)() => peek(0).isType(type) && peek(1).isType(type);
-		bool checkSameType()() => peek(0).type == peek(1).type;
 		int binaryOp(string op, alias check, string checkMsg, alias pre)(){
 			if(!check){
 				runtimeError(checkMsg.ptr);
@@ -234,7 +233,7 @@ struct VM{
 				}
 				static foreach(k, op; [ OpCode.Greater: ">", OpCode.Less: "<", OpCode.GreaterEqual: ">=", OpCode.LessEqual: "<=" ]){
 					case k:
-						if(binaryOp!(op, checkSameType, "Operands must be of the same type.", Value.Type.None))
+						if(binaryOp!(op, checkBinaryType!(Value.Type.Number), "Operands must be of the same type.", Value.Type.None))
 							return InterpretResult.RuntimeError;
 						break opSwitch;
 				}
diff --git a/test/all.d b/test/all.d
index a85a1fa..967795b 100755
--- a/test/all.d
+++ b/test/all.d
@@ -20,6 +20,8 @@ int main(){
 	"./test/while.lox".match("1 2  3 2 1  0 1  1 2  3 2 1  0 1 ".replace(' ', '\n'));
 	"./test/fields.lox".match("0 10 ".replace(' ', '\n'));
 
+	"./test/nan!=nan.lox".match("false ".replace(' ', '\n'));
+
 	"./test/ops.lox".match("1\n2\n3\n4\n5\n6\n7\ntrue\nfalse\ntrue\ntrue\nhello, world\n");
 	"./test/shortcircuit.lox".match("true\nAAAA!\nAAAA!\nAAAA?\n");
 	"./test/closure.lox".match("1\n2\n");
diff --git a/test/nan!=nan.lox b/test/nan!=nan.lox
new file mode 100644
index 0000000..d3d9ab1
--- /dev/null
+++ b/test/nan!=nan.lox
@@ -0,0 +1,4 @@
+
+var nan = 0 / 0;
+print nan == nan;
+