Define the behavior of FMA(inf, 0, qNaN)

1 files changed, 8 insertions, 0 deletions

diff --git a/src/f.tex b/src/f.tex
index e8a8306..9098012 100644
--- a/src/f.tex
+++ b/src/f.tex
@@ -449,6 +449,14 @@ FMADD.S computes {\em rs1$\times$rs2+rs3}; FMSUB.S computes
   -rs1$\times$rs2+rs3}; and FNMADD.S computes {\em
   -rs1$\times$rs2-rs3}.
 
+The fused multiply-add instructions must raise the invalid operation exception
+when the multiplicands are $\infty$ and zero, even when the addend is a quiet
+NaN.
+\begin{commentary}
+The IEEE 754-2008 standard permits, but does not require, raising the
+invalid exception for the operation \mbox{$\infty\times 0\ +$ qNaN}.
+\end{commentary}
+
 \vspace{-0.2in}
 \begin{center}
 \begin{tabular}{R@{}F@{}R@{}R@{}F@{}R@{}O}