(no commit message)

diff --git a/openpower/sv/po9_encoding/discussion.mdwn b/openpower/sv/po9_encoding/discussion.mdwn
index ce523708afabc483984f3452d37f977bf62b8405..fa3cbc1ea184eecc1644bc3f27199d0e5436b9c0 100644 (file)
--- a/openpower/sv/po9_encoding/discussion.mdwn
+++ b/openpower/sv/po9_encoding/discussion.mdwn
@@ -25,3 +25,14 @@ Length detection:
     else                     return 32
 ```
 
+Instruction allocation restrictions:
+
+* setvl is Unvectorizable but needs more space later: use 55-bit
+* likewise svshape svindex and svshape2, all these need 32-bit
+* svstep *is* Vectorizable but needs to be encoded 32-bit in order
+  to reduce loop-size
+* space for 32-bit instructions is needed: some instructions
+  just make no sense if done as 64-bit because they **replace**
+  two 32-bit instructions.
+* but those types of space-saving instructions
+  **also need to be Vectorizable*