From: lkcl <lkcl@web>
Date: Tue, 19 Apr 2022 12:07:43 +0000 (+0100)
Subject: (no commit message)
X-Git-Tag: opf_rfc_ls005_v1~2707
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=6251e5d5257e525b54c7722ba09e2683339f13a3;p=libreriscv.git

---

diff --git a/openpower/isa/svfixedarith.mdwn b/openpower/isa/svfixedarith.mdwn
index 23fad0402..e51e292b2 100644
--- a/openpower/isa/svfixedarith.mdwn
+++ b/openpower/isa/svfixedarith.mdwn
@@ -30,6 +30,17 @@ Special Registers Altered:
 
     None
 
+# Twin Multiply and Add  Doubleword
+
+<!-- SVP64: RC-as-source and RC-as-dest have separate EXTRA2 -->
+<!-- RT, RA have EXTRA2 marking. RB is always scalar (r0-31) -->
+* maddx RT,RA,RB,RC
+
+    prod[0:127] <- (RA) * (RB)
+    sum[0:127] <- EXTZ(RC) + prod
+    RT <- sum[64:127]
+    RC <- sum[0:63]
+
 # Twin Multiply and Subtract Doubleword
 
 * msubx RT,RA,RB,RC