Added English Language description for stbupx instruction

diff --git a/openpower/isa/pifixedstore.mdwn b/openpower/isa/pifixedstore.mdwn
index d3c2cf5f9844ce1d87f90289e5976db2dcaad1d2..ec2a0e3f07914f2dafac19eb952f4f25843d0719 100644 (file)
--- a/openpower/isa/pifixedstore.mdwn
+++ b/openpower/isa/pifixedstore.mdwn
@@ -43,6 +43,16 @@ Pseudo-code:
     MEM(ea, 1) <- (RS)[XLEN-8:XLEN-1]
     RA <- EA
 
+Description:
+
+    Let the effective address (EA) be the sum (RA)+ (RB).
+    (RS)[56:63] are stored into the byte in storage addressed
+    by EA.
+
+    EA is placed into register RA.
+
+    If RA=0, the instruction form is invalid.
+
 Special Registers Altered:
 
     None