From: lkcl <lkcl@web>
Date: Thu, 8 Jun 2023 04:46:00 +0000 (+0100)
Subject: (no commit message)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=14e51eb727e127a8851ff9164cd4e33d0c6c3348;p=libreriscv.git

---

diff --git a/openpower/sv/po9_encoding/discussion.mdwn b/openpower/sv/po9_encoding/discussion.mdwn
index 38ca9c2c7..55fa68d0a 100644
--- a/openpower/sv/po9_encoding/discussion.mdwn
+++ b/openpower/sv/po9_encoding/discussion.mdwn
@@ -46,21 +46,22 @@ Instruction allocation restrictions:
 
 # alternative 32-64 encoding (2)
 
-the complexity of attempting to fit
+the complexity of attempting to fit 32-bit instructions into
+PO9 is very high. encoding (1) attempts to fit `setvl` etc. into
+32-bit but it is very tight.
 
 
 ```
-|0-5| 6-27 28 29|30-31|32|33-35|36-37| 38-59 | 60-63 | Description      |
-|---|-----|-----|-----|--|-----|-----|-------|-------|------------------|
-|PO9| rm0 | 0 0 | 0 0 | 0  000   rm1 |  xxxx | 0000  | SVP64:EXT900     |
-|PO9| rm0 | 0 0 | 0 0 | 1  000   rm1 |  xxxx | 0000  | SSingle:EXT900   |
-|PO9| xxx | x 0 | 0 0 | x !zero      |  xxxx | !zero | 55-bit RESERVED  |
-|PO9| xxx | x 0 | 0 0 |              32-bit EXT900 (Vectorizable)       |
-|PO9| xxx | 1 1 | 0 0 |              32-bit EXT901 (Unvectorizable)     |
-|PO9|   !ZERO   | 0 0 |  1 | DWi                   | SSingle:EXT232-263 |
-|PO9|   0000    | 0 0 |  1 | DWi                   | Scalar EXT232-263  |
-|PO9|   nnnn    | 1 0 |  1 | DWi                   | SVP64:EXT232-263   |
-|PO9|   0000    | 0 1 | Defined Word-instruction   | 32-bit Unvec in 64b|
-|PO9|   !ZERO   | 0 1 | Defined Word-instruction   | SSingle:EXT000-063 |
-|PO9|   nnnn    | 1 1 | Defined Word-instruction   | SVP64:EXT000-063   |
+|0-5| 6-28|29 30 31|32|33-36|37 | 38-60 | 61-63 | Description      |
+|---|-----|--------|--|-----|---|-------|-------|------------------|
+|PO9| rm0 | 0  0 0 | 0 0000  rm1|  xxxx | 000   | SVP64:EXT900     |
+|PO9| rm0 | 0  0 0 | 1 0000  rm1|  xxxx | 000   | SSingle:EXT900   |
+|PO9| xxx | 0  0 0 | x !zero    |  xxxx | !zero | 55-bit RESERVED  |
+|PO9| xxx | 1  0 0 |            32-bit EXT900                      |
+|PO9|  !ZERO | 0 0 |  1 | DWi                 | SSingle:EXT232-263 |
+|PO9|  0000  | 0 0 |  1 | DWi                 | Scalar EXT232-263  |
+|PO9|  nnnn  | 1 0 |  1 | DWi                 | SVP64:EXT232-263   |
+|PO9|  0000  | 0 1 | Defined Word-instruction | 32-bit Unvec in 64b|
+|PO9|  !ZERO | 0 1 | Defined Word-instruction | SSingle:EXT000-063 |
+|PO9|  nnnn  | 1 1 | Defined Word-instruction | SVP64:EXT000-063   |
 ```