VM: Add Sub, Mul, Mod LSH, RSH

pkg/vm/stack/Int.go

@@ -27,11 +27,46 @@ func (i *Int) Equal(s *Int) bool {
 
 // Add will add two stackIntegers together
 func (i *Int) Add(s *Int) (*Int, error) {
+	return &Int{
+		val: new(big.Int).Add(i.val, s.val),
+	}, nil
+}
+
+// Sub will subtract two stackIntegers together
+func (i *Int) Sub(s *Int) (*Int, error) {
 	return &Int{
 		val: new(big.Int).Sub(i.val, s.val),
 	}, nil
 }
 
+// Mul will multiply two stackIntegers together
+func (i *Int) Mul(s *Int) (*Int, error) {
+	return &Int{
+		val: new(big.Int).Mul(i.val, s.val),
+	}, nil
+}
+
+// Mod will take the mod of two stackIntegers together
+func (i *Int) Mod(s *Int) (*Int, error) {
+	return &Int{
+		val: new(big.Int).Mod(i.val, s.val),
+	}, nil
+}
+
+// Rsh will shift the integer b to the right by `n` bits
+func (i *Int) Rsh(n *Int) (*Int, error) {
+	return &Int{
+		val: new(big.Int).Rsh(i.val, uint(n.val.Int64())),
+	}, nil
+}
+
+// Lsh will shift the integer b to the left by `n` bits
+func (i *Int) Lsh(n *Int) (*Int, error) {
+	return &Int{
+		val: new(big.Int).Lsh(i.val, uint(n.val.Int64())),
+	}, nil
+}
+
 // Integer will overwrite the default implementation
 // to allow go to cast this item as an integer.
 func (i *Int) Integer() (*Int, error) {