diff --git a/main/gbx/gbx_subr_extern.c b/main/gbx/gbx_subr_extern.c
index f6d57e8a4..22fc447ab 100644
--- a/main/gbx/gbx_subr_extern.c
+++ b/main/gbx/gbx_subr_extern.c
@@ -244,7 +244,8 @@ void SUBR_ptr(ushort code)
   ptr = SUBR_get_pointer_or_string(PARAM);
 	
 	CHECK_enter();
-	VALUE_read(RETURN, ptr, code & 0xF);
+  if (setjmp(CHECK_jump) == 0)	
+		VALUE_read(RETURN, ptr, code & 0xF);
 	CHECK_leave();
 	
 	if (CHECK_got_error())