Add text that was erroneously excised from Q chapter (in 2013!)

src/q.tex

@@ -150,6 +150,16 @@ \section{Quad-Precision Computational Instructions}
 
 \section{Quad-Precision Convert and Move Instructions}
 
+New floating-point-to-integer and integer-to-floating-point conversion
+instructions are added.  These instructions are defined analogously to the
+double-precision-to-integer and integer-to-double-precision conversion
+instructions.  FCVT.W.Q or FCVT.L.Q converts a quad-precision floating-point
+number to a signed 32-bit or 64-bit integer, respectively.  FCVT.Q.W or
+FCVT.Q.L converts a 32-bit or 64-bit signed integer, respectively, into a
+quad-precision floating-point number. FCVT.WU.Q, FCVT.LU.Q, FCVT.Q.WU, and
+FCVT.Q.LU variants convert to or from unsigned integer values.  FCVT.L[U].Q and
+FCVT.Q.L[U] are RV64-only instructions.
+
 \vspace{-0.2in}
 \begin{center}
 \begin{tabular}{R@{}F@{}R@{}R@{}F@{}R@{}O}