diff --git a/src/vm.cpp b/src/vm.cpp
index 8fd05f1..7f57206 100644
--- a/src/vm.cpp
+++ b/src/vm.cpp
@@ -114,11 +114,10 @@ Result<void> VM::vm_call_stdlib(Opcode& oc, StdlibFunction& fun) {
   uint64_t reg_end = (uint64_t)oc.arg2().arg;
 
   auto params = TRY(_stack.slice(reg_start + 1, reg_end));
+  _stack = TRY(_stack.set(reg_start + 1, TRY(params.copy_value())));
+  _stack = TRY(_stack.settop(reg_start + 2));
+  _stack = TRY(_stack.call(TRY(fun.copy_value()), reg_start, reg_start + 2));
 
-  auto res = TRY(call_stdlib_function(fun.fun_id(), params));
-  _stack = TRY(setreg(oc.arg1().arg, res));
-
-  _stack = TRY(_stack.incpc());
   return Result<void>();
 }
 
@@ -278,7 +277,24 @@ Result<void> VM::step_bytecode() {
   return Result<void>();
 }
 
-Result<void> VM::step_native() { return ERROR(NotImplemented); }
+Result<void> VM::step_native() {
+  // foo
+  auto fun = TRY(_stack.fun());
+  if (!fun.is<StdlibFunction>()) return ERROR(TypeMismatch);
+  auto fun_id = fun.to<StdlibFunction>()->fun_id();
+
+  auto params = TRY(_stack.get(0));
+  if (!params.is<Array>()) return ERROR(TypeMismatch);
+
+  auto res = TRY(call_stdlib_function(fun_id, *params.to<Array>()));
+
+  auto top = TRY(_stack.size());
+  _stack = TRY(_stack.set(top, res));
+  _stack = TRY(_stack.ret(top));
+
+  _stack = TRY(_stack.incpc());
+  return Result<void>();
+}
 
 Result<void> VM::step() {
   auto fun = TRY(_stack.fun());