programmers note about RC1 with DD-FF-LDST

diff --git a/openpower/sv/ldst.mdwn b/openpower/sv/ldst.mdwn
index 1623f513fd16cfc4c9f05df97ec0767f1a43b450..614dc6ed09d27ac58e6737d542bb795e395c12b8 100644 (file)
--- a/openpower/sv/ldst.mdwn
+++ b/openpower/sv/ldst.mdwn
@@ -477,6 +477,10 @@ nodes.  If VLi=1 it will load the NULL pointer into the Vector of results.
 If however VLi=0 it will *exclude* the NULL pointer by truncating VL to
 one Element earlier.
 
+*Programmer's Note: by also setting the RC1 qualifier as well as setting
+VLi=1 it is possible to establish a Predicate Mask such that the first
+zero in the predicate will be the NULL pointer*
+
 ```
    RT=1 # vec - deliberately overlaps by one with RA
    RA=0 # vec - first one is valid, contains ptr