From: lkcl <lkcl@web>
Date: Sun, 30 Apr 2023 02:00:45 +0000 (+0100)
Subject: (no commit message)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=18c460806c78c9a85894d838d4e854ea63de2b73;p=libreriscv.git

---

diff --git a/openpower/sv/rfc/ls012.mdwn b/openpower/sv/rfc/ls012.mdwn
index 99fcbec2e..a31ce8c97 100644
--- a/openpower/sv/rfc/ls012.mdwn
+++ b/openpower/sv/rfc/ls012.mdwn
@@ -636,6 +636,11 @@ the saving in power consumption and time was definitely worthwhile,
 and it neatly illustrates a counter-example to trying to make one
 instruction do too much.
 
+Another good example is the Integer Twin-butterfly instructions,
+`((a +/- b) * c) >> sh` which require **eight** instructions and
+temporary registers. Although expensive they save so many other
+instructions it is hard to disregard them.
+
 **Summary**
 
 There are many tradeoffs here, it is a huge list of considerations: any