diff --git a/src/bytecode.c b/src/bytecode.c
index 96f1f905812..c5cc6590121 100644
--- a/src/bytecode.c
+++ b/src/bytecode.c
@@ -291,7 +291,7 @@ enum byte_code_op
 /* Fetch two bytes from the bytecode stream and make a 16-bit number
    out of them.  */
 
-#define FETCH2 (op = FETCH, op + (FETCH << 8))
+#define FETCH2 (op = FETCH, op | (FETCH << 8))
 
 /* Push X onto the execution stack.  The expression X should not
    contain TOP, to avoid competing side effects.  */