From 1f0393b6c1a462f007f5b65c4d3aef134b32fd72 Mon Sep 17 00:00:00 2001
From: lkcl <lkcl@web>
Date: Thu, 15 Sep 2022 13:16:25 +0100
Subject: [PATCH]

---
 openpower/sv/rfc/ls001.mdwn | 34 ++++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 14 deletions(-)

diff --git a/openpower/sv/rfc/ls001.mdwn b/openpower/sv/rfc/ls001.mdwn
index dad82b579..b68822561 100644
--- a/openpower/sv/rfc/ls001.mdwn
+++ b/openpower/sv/rfc/ls001.mdwn
@@ -710,23 +710,29 @@ of this RFC.
 
 **legal, scalar and vector**
 
-| width | assembler | prefix (if any) | suffix    | description   |
-|-------|-----------|-----------------|-----------|---------------|
-| 32bit | fishmv    | none            | 0x12345678| scalar EXT0nn |
-| 64bit | sv.fishmv | 0x27000000      | 0x12345678| vector SVP64:EXT2nn |
+| width | assembler | prefix?      | suffix    | description   |
+|-------|-----------|--------------|-----------|---------------|
+| 32bit | fishmv    | none         | 0x12345678| scalar EXT0nn |
+| 64bit | ss.fishmv | 0x26!zero    | 0x12345678| scalar SVP64Single:EXT0nn |
+| 64bit | sv.fishmv | 0x27nnnnnn   | 0x12345678| vector SVP64:EXT0nn |
 
 OR:
 
-| width | assembler | prefix (if any) | suffix    | description   |
-|-------|-----------|-----------------|-----------|---------------|
-| 64bit | fishmv    | 0x24000000      | 0x12345678| scalar EXT2nn |
-| 64bit | sv.fishmv | 0x26000000      | 0x12345678| vector SVP64:EXT0nn |
-
-* 32bit fishmv EXT0nn 0x12345678 or
-  64bit scalar EXT2nn 0x240000000 0x12345678 (typo removed)
-* vector fishmv 0x27nnnnnn 0x12345678
-
-here the encodings are the same, 0x12345678 means the same thing in both cases.  (and SVP64Single, wherever it is, whenever it is).
+| width | assembler | prefix?      | suffix    | description   |
+|-------|-----------|--------------|-----------|---------------|
+| 64bit | fishmv    | 0x24000000   | 0x12345678| scalar EXT2nn |
+| 64bit | ss.fishmv | 0x24!zero    | 0x12345678| scalar SVP64Single:EXT2nn |
+| 64bit | sv.fishmv | 0x26nnnnnn   | 0x12345678| vector SVP64:EXT2nn |
+
+Here the encodings are the same, 0x12345678 means the same thing in 
+all cases. Anything other than this risks either damage (truncation
+of capabilities of Simple-V) or far greater complexity in the
+Decode Phase.
+
+A *potential* compromise is to reserve certain EXT2nn POs right
+across the board
+(in the Scalar Suffix side, irrespective of Prefix), some allocated
+to Simple-V, some not.  
 
 example, legal (sort-of) (edit, typo corrected)
 
-- 
2.30.2