diff --git a/book/insnformats.tex b/book/insnformats.tex
index dd1d135..7d6d68b 100644
--- a/book/insnformats.tex
+++ b/book/insnformats.tex
@@ -549,3 +549,5 @@
 \newcommand\insn[1]{{\tt #1}}
 
 \newcommand\rvddt{{\tt rvddt}}
+
+\newcommand\hex[1]{{\tt 0x#1}}