diff --git a/include/picrin/proc.h b/include/picrin/proc.h
index 8d38d974..ea540cba 100644
--- a/include/picrin/proc.h
+++ b/include/picrin/proc.h
@@ -17,4 +17,6 @@ struct pic_proc {
 
 #define pic_proc_ptr(o) ((struct pic_proc *)o.u.data)
 
+#define pic_proc_cfunc_p(o) (pic_proc_ptr(o)->cfunc_p)
+
 #endif
diff --git a/src/vm.c b/src/vm.c
index ea75738d..f982b85f 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -322,13 +322,14 @@ pic_value
 pic_run(pic_state *pic, struct pic_proc *proc, pic_value args)
 {
   struct pic_code *pc;
+  pic_callinfo *ci;
   int ai = pic_gc_arena_preserve(pic);
 
   pc = proc->u.irep->code;
 
-  PUSHCI();
-  pic->ci->proc = proc;
-  pic->ci->argc = 0;
+  ci = PUSHCI();
+  ci->proc = proc;
+  ci->argc = 0;
 
   VM_LOOP {
     CASE(OP_PUSHNIL) {
@@ -354,16 +355,21 @@ pic_run(pic_state *pic, struct pic_proc *proc, pic_value args)
     CASE(OP_CALL) {
       pic_value c;
       struct pic_proc *proc;
-      pic_callinfo *ci;
 
       pic_gc_protect(pic, c = POP());
       proc = pic_proc_ptr(c);
       ci = PUSHCI();
       ci->proc = proc;
       ci->argc = pc->u.i;
-      PUSH(proc->u.cfunc(pic));
-      pic->sp -= ci->argc;
-      POPCI();
+      if (pic_proc_cfunc_p(c)) {
+	PUSH(proc->u.cfunc(pic));
+	pic->sp -= ci->argc;
+	POPCI();
+	ci = pic->ci - 1;
+      }
+      else {
+	pic_raise(pic, "closure call not suppoted");
+      }
       pic_gc_arena_restore(pic, ai);
       NEXT;
     }