Improve table of RAS hints for JALR instructions (#563)

1 files changed, 11 insertions, 10 deletions

diff --git a/src/rv32.tex b/src/rv32.tex
index bb7348b..b28fd7a 100644
--- a/src/rv32.tex
+++ b/src/rv32.tex
@@ -822,24 +822,25 @@ detection of instructions used for procedure calls and returns to be
 effective.  For RISC-V, hints as to the instructions' usage are encoded
 implicitly via the register numbers used.  A JAL instruction should
 push the return address onto a return-address stack (RAS) only when
-{\em rd}$=${\tt x1}/{\tt x5}.  JALR instructions should push/pop a
+{\em rd} is {\tt x1} or {\tt x5}.  JALR instructions should push/pop a
 RAS as shown in the Table~\ref{rashints}.
 \begin{table}[hbt]
 \centering
 \begin{tabular}{|c|c|c|l|}
   \hline
-  \em rd & \em rs1 & {\em rs1}$=${\em rd} & RAS action \\
+  \textit{rd} is \texttt{x1}/\texttt{x5}
+      & \textit{rs1} is \texttt{x1}/\texttt{x5}
+            & \textit{rd}$=$\textit{rs1} & RAS action \\
   \hline
-  !{\em link} & !{\em link} & - & none \\
-  !{\em link} &  {\em link} & - & pop \\
-   {\em link} & !{\em link} & - & push  \\
-   {\em link} &  {\em link} & 0 & pop, then push \\
-   {\em link} &  {\em link} & 1 & push \\
+  No  & No  & --  & None \\
+  No  & Yes & --  & Pop \\
+  Yes & No  & --  & Push \\
+  Yes & Yes & No  & Pop, then push \\
+  Yes & Yes & Yes & Push \\
    \hline
 \end{tabular}
-\caption{Return-address stack prediction hints encoded in register
-  specifiers used in the instruction.  In the above, {\em link} is
-  true when the register is either {\tt x1} or {\tt x5}.}
+\caption{Return-address stack prediction hints encoded in the register
+  operands of a JALR instruction.}
 \label{rashints}
 \end{table}