From: lkcl <lkcl@web>
Date: Tue, 19 Jan 2021 13:44:44 +0000 (+0000)
Subject: (no commit message)
X-Git-Tag: convert-csv-opcode-to-binary~407
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=adabaaa74c78cc282c2c0cfd5da75b63cc526017;p=libreriscv.git

---

diff --git a/openpower/sv/remap.mdwn b/openpower/sv/remap.mdwn
index 5a8c537d4..2ac51201c 100644
--- a/openpower/sv/remap.mdwn
+++ b/openpower/sv/remap.mdwn
@@ -178,5 +178,13 @@ The reason for allowing SUBVL Remaps is that some regular patterns using Swizzle
 
 An example where SUBVL Remap is appropriate is the Rijndael MixColumns stage:
 
-<img src="https://en.wikipedia.org/wiki/Advanced_Encryption_Standard#/media/File:AES-MixColumns.svg" size="400px" />
+<img src="https://upload.wikimedia.org/wikipedia/commons/thumb/7/76/AES-MixColumns.svg/600px-AES-MixColumns.svg.png" width="400px" />
+
+A 2D REMAP allows:
+
+* the column bytes (as a vec4) to be iterated over as an inner loop.
+* the columns themselves to be iterated as an outer loop
+* a 32 bit `GF(256)` multiply on the vec4 to be performed.
+
+This entirely in-place without special 128-bit opcodes.