From: Konstantinos Margaritis <konstantinos.margaritis@vectorcamp.gr>
Date: Fri, 21 Jul 2023 10:23:39 +0000 (+0000)
Subject: fix wrong paste of pseudo-code
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=c2fac68d1db95c67e3fa5fa9b1fdef5d97e3f1a1;p=libreriscv.git

fix wrong paste of pseudo-code
---

diff --git a/openpower/sv/twin_butterfly.mdwn b/openpower/sv/twin_butterfly.mdwn
index 26b2484ef..faee1c2e9 100644
--- a/openpower/sv/twin_butterfly.mdwn
+++ b/openpower/sv/twin_butterfly.mdwn
@@ -147,35 +147,30 @@ A-Form
 
 Pseudo-code:
 
+```
     n <- SH
     prod <- MULS(RB, RA)
     if n = 0 then
         prod_lo <- prod[XLEN:(XLEN*2) - 1]
         RT <- (RT) + prod_lo
-    n <- SH
-    sum <- (RT) + (RA)
-    diff <- (RT) - (RA)
-    prod1 <- MULS(RB, sum)
-    prod1_lo <- prod1[XLEN:(XLEN*2)-1]
-    prod2 <- MULS(RB, diff)
-    prod2_lo <- prod2[XLEN:(XLEN*2)-1]
-    if n = 0 then
-        RT <- prod1_lo
-        RS <- prod2_lo
+        RS <- (RS) - prod_lo
     else
-        round <- [0]*XLEN
-        round[XLEN -n] <- 1
-        prod1_lo <- prod1_lo + round
-        prod2_lo <- prod2_lo + round
-        m <- MASK(n, (XLEN-1))
-        res1 <- ROTL64(prod1_lo, XLEN-n) & m
-        res2 <- ROTL64(prod2_lo, XLEN-n) & m
-        signbit1 <- prod1_lo[0]
-        signbit2 <- prod2_lo[0]
+        res1[0:XLEN*2-1] <- (EXTSXL((RT)[0], 1) || (RT)) + prod
+        res2[0:XLEN*2-1] <- (EXTSXL((RS)[0], 1) || (RS)) - prod
+        round <- [0]*XLEN*2
+        round[XLEN*2 - n] <- 1
+        res1 <- res1 + round
+        res2 <- res2 + round
+        signbit1 <- res1[0]
+        signbit2 <- res2[0]
+        m <- MASK(XLEN -n - 2, XLEN - 1)
+        res1 <- res1[XLEN - n:XLEN*2 - n -1]
+        res2 <- res2[XLEN - n:XLEN*2 - n -1]
         smask1 <- ([signbit1]*XLEN) & ¬m
         smask2 <- ([signbit2]*XLEN) & ¬m
         RT <- (res1 | smask1)
         RS <- (res2 | smask2)
+```
 
 Special Registers Altered: