From: lkcl <lkcl@web>
Date: Tue, 4 Jan 2022 16:07:16 +0000 (+0000)
Subject: (no commit message)
X-Git-Tag: opf_rfc_ls005_v1~3271
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=a17028ebebf3f49ce09dd69d0b6b2b8eb12a5bf1;p=libreriscv.git

---

diff --git a/openpower/sv/bitmanip.mdwn b/openpower/sv/bitmanip.mdwn
index fb052cbfd..b8e27037c 100644
--- a/openpower/sv/bitmanip.mdwn
+++ b/openpower/sv/bitmanip.mdwn
@@ -308,7 +308,11 @@ uint_xlen_t bmextrev(RA, RB, sh)
 
 # grev
 
-based on RV bitmanip, this is also known as a butterfly network
+based on RV bitmanip, this is also known as a butterfly network. however
+where a butterfly network allows setting of every crossbar setting in
+every row and every column, generalised-reverse (grev) only allows
+a per-row decision: every entry in the same row must either switch or
+not-switch.
 
 <img src="https://upload.wikimedia.org/wikipedia/commons/thumb/8/8c/Butterfly_Network.jpg/474px-Butterfly_Network.jpg" />