From ac7c9441cce1a268a1396bf86f01dd46ffbe8406 Mon Sep 17 00:00:00 2001
From: Konstantinos Margaritis <konstantinos.margaritis@vectorcamp.gr>
Date: Fri, 28 Apr 2023 11:48:48 +0000
Subject: [PATCH] use proper register sizes

---
 openpower/isa/butterfly.mdwn | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/openpower/isa/butterfly.mdwn b/openpower/isa/butterfly.mdwn
index 0d799a68..b6fecae2 100644
--- a/openpower/isa/butterfly.mdwn
+++ b/openpower/isa/butterfly.mdwn
@@ -13,12 +13,12 @@ Pseudo-code:
     n <- XLEN-SH
     sum <- (RT) + (RA)
     diff <- (RT) - (RA)
-    prod1 <- MULS(RB, sum)
-    prod2 <- MULS(RB, diff)
+    prod1[0:(XLEN*2)-1] <- MULS(RB, sum)
+    prod2[0:(XLEN*2)-1] <- MULS(RB, diff)
     res1 <- prod1[XLEN/2-SH:XLEN-1-SH]
     res2 <- prod2[XLEN/2-SH:XLEN-1-SH]
-    RT <- (RT) + res1
-    RS <- (RS) + res2
+    RT <- (RT) + EXTS(res1)
+    RS <- (RS) + EXTS(res2)
 
 Special Registers Altered:
 
-- 
2.30.2