Improve commentary on CSR ordering

1 files changed, 8 insertions, 5 deletions

diff --git a/src/csr.tex b/src/csr.tex
index 1118fb1..f73a8cd 100644
--- a/src/csr.tex
+++ b/src/csr.tex
@@ -181,9 +181,12 @@ scheme.
 \end{commentary}
 
 \begin{commentary}
-Some CSRs, including those defined in Chapter~\ref{sec:single-float}, are not
-accessible to other harts or devices and cause no side effects visible to
-other harts or devices when accessed locally.  Accesses to such CSRs can be
-freely reordered with respect to FENCE instructions without violating this
-specification.
+These CSR-ordering constraints are imposed primarily to support ordering
+memory and memory-mapped I/O accesses with respect to reads of the {\tt time}
+CSR.  With the exception of the {\tt time}, {\tt cycle}, and {\tt mcycle}
+CSRs, the CSRs defined thus far in Volumes I and II of this specification are
+not directly accessible to other harts or devices and cause no side effects
+visible to other harts or devices.  Thus, accesses to CSRs other than the
+aforementioned three can be freely reordered with respect to FENCE
+instructions without violating this specification.
 \end{commentary}