From: Andrey Miroshnikov <andrey@technepisteme.xyz>
Date: Thu, 9 Nov 2023 18:36:00 +0000 (+0000)
Subject: Add table of row/column indices
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=68c1a4d9d3200c4b625e1a84d962b9234128e6b6;p=libreriscv.git

Add table of row/column indices
---

diff --git a/openpower/sv/cookbook/remap_matrix.mdwn b/openpower/sv/cookbook/remap_matrix.mdwn
index 146457659..701c9c01c 100644
--- a/openpower/sv/cookbook/remap_matrix.mdwn
+++ b/openpower/sv/cookbook/remap_matrix.mdwn
@@ -358,6 +358,34 @@ REMAP, or setvl is setup.
 Assigns the configured SVSHAPEs to the relevant operand/result registers
 of the consecutive instruction/s (depending on if REMAP is set to persistent).
 
+The index table shown for the inner method above shows indices for a 'flattened'
+matrix (how it would be arranged in sequential GPR registers), whereas
+SVSHAPE0, 1, 2 registers setup the indices in relation to rows and columns
+of the matrix.
+
+This is how the indices compare:
+
+```
+                             Row/Column Indices
+    Flattened Indices     | Mat X | Mat Y | Mat Z |
+| Mat X | Mat Y | Mat Z | | r   c | r   c | r   c |
+|   0   |   0   |   0   | | 0   0 | 0   0 | 0   0 |
+|   0   |   1   |   1   | | 0   0 | 0   1 | 0   1 |
+|   3   |   0   |   2   | | 1   0 | 0   0 | 1   0 |
+|   3   |   1   |   3   | | 1   0 | 0   1 | 1   1 |
+|   1   |   2   |   0   | | 0   1 | 1   0 | 0   0 |
+|   1   |   3   |   1   | | 0   1 | 1   1 | 0   1 |
+|   4   |   2   |   2   | | 1   1 | 1   0 | 1   0 |
+|   4   |   3   |   3   | | 1   1 | 1   1 | 1   1 |
+|   2   |   4   |   0   | | 0   2 | 2   0 | 0   0 |
+|   2   |   5   |   1   | | 0   2 | 2   1 | 0   1 |
+|   5   |   4   |   2   | | 1   2 | 2   0 | 1   0 |
+|   5   |   5   |   3   | | 1   2 | 2   1 | 1   1 |
+```
+
+See [[openpower/sv/remap]] Section 3.3 Matrix Mode for more information on
+the index sequences which can be produced with SVSHAPE SPRs.
+
 ## maddld - Multiply-Add Low Doubleword VA-form
 
 ```