From: lkcl <lkcl@web>
Date: Tue, 14 Jun 2022 20:42:06 +0000 (+0100)
Subject: (no commit message)
X-Git-Tag: opf_rfc_ls005_v1~1776
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=e99424662b7cb5580b14863252fccc40f6d383a5;p=libreriscv.git

---

diff --git a/openpower/sv/svp64_quirks.mdwn b/openpower/sv/svp64_quirks.mdwn
index 3872e635b..1af27b60d 100644
--- a/openpower/sv/svp64_quirks.mdwn
+++ b/openpower/sv/svp64_quirks.mdwn
@@ -501,3 +501,13 @@ in Vertical-First Mode.
 This is conceptually quite easy to keep in mind that a Vertical-First
 instruction does one element at a time, and when SUBVL is set,
 that "element" in essence becomes a vec2/3/4.
+
+# Swizzle and Pack/Unpack
+
+These are both so weird it's best to just read the pages in full
+and pay attention: [[sv/mv.swizzle]] and [[sv/mv.vec]].
+Swizzle Moves only engage with vec2/3/4, *reordering* the copying
+based on an immediate supplied by the instruction.  The fun
+comes when Pack/Unpack are enabled, and it is really important
+to be aware how the Arrays of vec2/3/4 become re-ordered
+*and swizzled at the same time*.