diff --git a/asm/assembler/constpool.c b/asm/assembler/constpool.c
index 9fa21c1..30c7136 100644
--- a/asm/assembler/constpool.c
+++ b/asm/assembler/constpool.c
@@ -66,9 +66,7 @@ static ivy_extended_data_key write_string(struct ivy_assembler *as, const char *
 
 	key = assembler_write_extended_data(as, &str, sizeof str);
 
-	/* include the trailing null terminator. */
-	assembler_write_extended_data(as, s, len + 1);
-
+	assembler_write_extended_data(as, s, len);
 	put_cached_string(scope, s, key);
 
 	return key;