diff --git a/common/interp.h b/common/interp.h
index a63b14f..84b0aad 100644
--- a/common/interp.h
+++ b/common/interp.h
@@ -25,7 +25,7 @@ static cell_t *forth_run(cell_t *init_rp) {
     EXTRA_OPCODE_LIST
     OPCODE_LIST
 #undef XV
-    0, 0, 0,
+    0, 0, 0, 0, 0,
   };
 
   if (!init_rp) {
diff --git a/common/opcodes.h b/common/opcodes.h
index 8f36648..e57b038 100644
--- a/common/opcodes.h
+++ b/common/opcodes.h
@@ -71,7 +71,7 @@ typedef struct {
       uint8_t flags, name_length;
       uint16_t vocabulary;
     };
-    cell_t multi;
+    cell_t multi;  // Forces cell alignment throughout.
   };
   const void *code;
 } BUILTIN_WORD;