diff --git a/src/asm/rgbasm.1 b/src/asm/rgbasm.1
index af1213f2..5d87516f 100644
--- a/src/asm/rgbasm.1
+++ b/src/asm/rgbasm.1
@@ -22,6 +22,7 @@
 .Op Fl o Ar out_file
 .Op Fl p Ar pad_value
 .Op Fl r Ar recursion_depth
+.Op Fl W Ar warning
 .Ar
 .Sh DESCRIPTION
 The