diff --git a/advsync/memorybarriers.tex b/advsync/memorybarriers.tex
index 7b50511..f94b113 100644
--- a/advsync/memorybarriers.tex
+++ b/advsync/memorybarriers.tex
@@ -1261,15 +1261,15 @@
 locations, but the order in which the control registers are accessed is very
 important.  For instance, imagine an Ethernet card with a set of internal
 registers that are accessed through an address port register~(A) and a data
-port register~(D).  To read internal register~5, the following code might then
-be used:
+port register~(D).  To read internal register~5, the following code (in C)
+might then be used:
 
 \vspace{5pt}
 \begin{minipage}[t]{\columnwidth}
 \scriptsize
 \begin{verbatim}
-*A = 5;
-x = *D;
+WRITE_ONCE(*A, 5);
+x = READ_ONCE(*D);
 \end{verbatim}
 \vspace{1pt}
 \end{minipage}