diff --git a/src/mes.c b/src/mes.c
index 86619286..69884f72 100644
--- a/src/mes.c
+++ b/src/mes.c
@@ -1,6 +1,7 @@
 /* -*-comment-start: "//";comment-end:""-*-
  * GNU Mes --- Maxwell Equations of Software
  * Copyright © 2016,2017,2018,2019,2020,2021 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ * Copyright © 2021 W. J. van der Laan <laanwj@protonmail.com>
  *
  * This file is part of GNU Mes.
  *
@@ -61,6 +62,10 @@ mes_environment (int argc, char **argv)
   arch = "arm";
 #elif __x86_64__
   arch = "x86_64";
+#elif __riscv_xlen == 32
+  arch = "riscv32";
+  #elif __riscv_xlen == 64
+  arch = "riscv64";
 #else
 #error arch not supported
 #endif