diff --git a/packages/script/runtime.go b/packages/script/runtime.go
index 6a289206..99648298 100644
--- a/packages/script/runtime.go
+++ b/packages/script/runtime.go
@@ -254,8 +254,12 @@ func (rt *RunTime) callFunc(cmd uint16, obj *ObjInfo) (err error) {
 			pars[count-i] = reflect.Zero(reflect.TypeOf(``))
 		}
 	}
-	if i > 0 {
+	if i > 0 && size-i >= 0 {
 		pars[in-1] = reflect.ValueOf(rt.stack[size-i : size])
+	} else {
+		if !pars[in-1].IsValid() {
+			pars[in-1] = reflect.Zero(finfo.Params[in-1])
+		}
 	}
 	if finfo.Name == `ExecContract` && (pars[2].Kind() != reflect.String || !pars[3].IsValid()) {
 		return fmt.Errorf(`unknown function %v`, pars[1])
@@ -265,6 +269,9 @@ func (rt *RunTime) callFunc(cmd uint16, obj *ObjInfo) (err error) {
 	} else {
 		result = foo.Call(pars)
 	}
+	if shift < 0 {
+		shift = 0
+	}
 	rt.resetByIdx(shift)
 	if stack != nil {
 		stack.PopStack(finfo.Name)