diff --git a/Makefile b/Makefile
index 59f3ada0..677a3673 100644
--- a/Makefile
+++ b/Makefile
@@ -6,7 +6,7 @@ build:
 	cd src; \
 	yacc -d parse.y; \
 	lex scan.l
-	 $(CC) -Wall -o bin/picrin -I./include -lreadline src/main.c src/state.c src/gc.c src/pair.c src/port.c src/symbol.c src/value.c src/y.tab.c src/lex.yy.c src/bool.c src/vm.c src/init.c src/number.c src/time.c src/codegen.c
+	 $(CC) -Wall -o bin/picrin -I./include -lreadline src/main.c src/state.c src/gc.c src/pair.c src/port.c src/symbol.c src/value.c src/y.tab.c src/lex.yy.c src/bool.c src/vm.c src/init.c src/number.c src/time.c src/codegen.c src/error.c
 
 clean:
 	rm -f src/y.tab.c src/y.tab.h src/lex.yy.c
diff --git a/src/error.c b/src/error.c
new file mode 100644
index 00000000..9efcea1d
--- /dev/null
+++ b/src/error.c
@@ -0,0 +1,11 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "picrin.h"
+
+void
+pic_raise(pic_state *pic, const char *str)
+{
+  puts(str);
+  abort();
+}
diff --git a/src/vm.c b/src/vm.c
index 01ba27cd..bbe0c4ea 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -1,4 +1,3 @@
-#include <stdlib.h>
 #include <stdio.h>
 #include <stdarg.h>
 
@@ -64,7 +63,6 @@ pic_value
 pic_run(pic_state *pic, struct pic_proc *proc, pic_value args)
 {
   struct pic_code *pc;
-  pic_value val;
   int ai = pic_gc_arena_preserve(pic);
 
 #if PIC_DIRECT_THREADED_VM
@@ -232,33 +230,25 @@ pic_run(pic_state *pic, struct pic_proc *proc, pic_value args)
       NEXT;
     }
     CASE(OP_STOP) {
-      goto STOP;
-    }
-  } VM_LOOP_END;
+      pic_value val;
 
- STOP:
-  val = POP();
+      val = POP();
 
 #if VM_DEBUG
-  puts("**VM END STATE**");
-  printf("stbase = %p\nsp = %p\n", pic->stbase, pic->sp);
-  printf("cibase = %p\nci = %p\n", pic->cibase, pic->ci);
-  if (pic->stbase != pic->sp) {
-    pic_value *sp;
-    printf("* stack trace:");
-    for (sp = pic->stbase; pic->sp != sp; ++sp) {
-      pic_debug(pic, *sp);
-      puts("");
-    }
-  }
+      puts("**VM END STATE**");
+      printf("stbase = %p\nsp = %p\n", pic->stbase, pic->sp);
+      printf("cibase = %p\nci = %p\n", pic->cibase, pic->ci);
+      if (pic->stbase != pic->sp) {
+	pic_value *sp;
+	printf("* stack trace:");
+	for (sp = pic->stbase; pic->sp != sp; ++sp) {
+	  pic_debug(pic, *sp);
+	  puts("");
+	}
+      }
 #endif
 
-  return val;
-}
-
-void
-pic_raise(pic_state *pic, const char *str)
-{
-  puts(str);
-  abort();
+      return val;
+    }
+  } VM_LOOP_END;
 }