(no commit message)

diff --git a/openpower/sv/svp64.mdwn b/openpower/sv/svp64.mdwn
index 6d05c31da5bfde0db2caf8d70127aecd744358c3..bb89bb886b19f9b375f20cd9d3651c408c16561c 100644 (file)
--- a/openpower/sv/svp64.mdwn
+++ b/openpower/sv/svp64.mdwn
@@ -174,13 +174,20 @@ Following the prefix will be the suffix: this is simply a 32-bit v3.0B / v3.1
 instruction.  That instruction becomes "prefixed" with the SVP context: the
 Remapped Encoding field (RM).
 
+It is important to note that unlike v3.1 64-bit prefixed instructions
+there is insufficient space in `RM` to provide identification of
+any SVP64 Fields without first partially decoding the
+32-bit suffix.  Extreme caution and care must therefore be taken
+when extending SVP64 in future, to not create unnecessary relationships
+between prefix and suffix that could complicate decoding, adding latency.
+
 # Common RM fields
 
 The following fields are common to all Remapped Encodings:
 
 | Field Name | Field bits | Description                            |
 |------------|------------|----------------------------------------|
-| MASKMODE   | `0`        | Execution (predication) Mask Kind                 |
+| MASKMODE   | `0`        | Execution (predication) Mask Kind      |
 | MASK          | `1:3`      | Execution Mask                      |
 | ELWIDTH       | `4:5`      | Element Width                       |
 | ELWIDTH_SRC   | `6:7`      | Element Width for Source      |