From: lkcl <lkcl@web>
Date: Sun, 10 Jul 2022 13:57:48 +0000 (+0100)
Subject: (no commit message)
X-Git-Tag: opf_rfc_ls005_v1~1222
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=1a190fc356699e595e48f362bc45e28d6c193b59;p=libreriscv.git

---

diff --git a/openpower/sv/remap.mdwn b/openpower/sv/remap.mdwn
index 7cadb81b1..0db2918f0 100644
--- a/openpower/sv/remap.mdwn
+++ b/openpower/sv/remap.mdwn
@@ -376,6 +376,18 @@ In essence, `mm=0` is intended for use to set as much of the
 REMAP State SPRs as practical with a single instruction,
 whilst `mm=1` is intended to be a little more refined.
 
+**Usage guidelines**
+
+* **Disable 2D mapping**: to only perform Indexing without
+ reordering use `SVd=1,sk=0,yx=0` (or set SVd to a value larger
+ or equal to VL)
+* **Modulo 1D mapping**: to perform Indexing cycling through the
+ first N Indices use `SVd=N,sk=0,yx=0` where `VL>N`. There is
+ no requirement to set VL equal to a multiple of N.
+ 
+Beyond these mappings it becomes necessary to write directly to
+the SVSTATE SPRs manually.
+
 # REMAP Matrix pseudocode
 
 The algorithm below shows how REMAP works more clearly, and may be