diff --git a/sysdeps/mips/dec/bytesex.h b/sysdeps/mips/dec/bytesex.h
new file mode 100644
index 0000000000..157bc44d06
--- /dev/null
+++ b/sysdeps/mips/dec/bytesex.h
@@ -0,0 +1,4 @@
+/* The MIPS architecture has selectable endianness.
+   The DECstation uses little-endian mode.  */
+
+#define __BYTE_ORDER __LITTLE_ENDIAN
diff --git a/sysdeps/mips/p40/bytesex.h b/sysdeps/mips/p40/bytesex.h
new file mode 100644
index 0000000000..e4b0119433
--- /dev/null
+++ b/sysdeps/mips/p40/bytesex.h
@@ -0,0 +1,4 @@
+/* The MIPS has selectable endianness.
+   The Japanese homebrew P40 architecture uses big-endian mode.  */
+
+#define __BYTE_ORDER __BIG_ENDIAN