From d7b016e8f349c0117cdf26473bcd029d5f176f88 Mon Sep 17 00:00:00 2001
From: David Harris <David_Harris@hmc.edu>
Date: Fri, 12 Jan 2024 18:12:52 -0800
Subject: [PATCH 1/2] Cleaned up Zicond implementation

---
 src/ieu/alu.sv | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/ieu/alu.sv b/src/ieu/alu.sv
index b13c3a65c..4c296fda2 100644
--- a/src/ieu/alu.sv
+++ b/src/ieu/alu.sv
@@ -101,11 +101,16 @@ module alu import cvw::*; #(parameter cvw_t P) (
 
   // Zicond block
   if (P.ZICOND_SUPPORTED) begin: zicond
-    logic  BZero, KillB;
+    logic  BZero;
+    
     assign BZero = (B == 0); // check if rs2 = 0
     // Create a signal that is 0 when czero.* instruction should clear result
     // If B = 0 for czero.eqz or if B != 0 for czero.nez
-    assign KillB = BZero & CZero[0] | ~BZero & CZero[1];
-    assign ZeroCondMaskInvB = |CZero ? {P.XLEN{~KillB}} : CondMaskInvB; // extend to full width
+    always_comb 
+     case (CZero)
+        2'b01:   ZeroCondMaskInvB = {P.XLEN{~BZero}}; // czero.eqz: kill if B = 0
+        2'b10:   ZeroCondMaskInvB = {P.XLEN{BZero}};  // czero.nez: kill if B != 0
+        default: ZeroCondMaskInvB = CondMaskInvB;     // otherwise normal behavior
+      endcase
   end else assign ZeroCondMaskInvB = CondMaskInvB; // no masking if Zicond is not supported
 endmodule

From a9acb5f269635d0bec9a5d19dc7e31a9a818b14b Mon Sep 17 00:00:00 2001
From: David Harris <David_Harris@hmc.edu>
Date: Fri, 12 Jan 2024 18:13:11 -0800
Subject: [PATCH 2/2] Added comments with a way to build Sail on RedHat

---
 bin/wally-tool-chain-install.sh | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/bin/wally-tool-chain-install.sh b/bin/wally-tool-chain-install.sh
index f690bfac1..7ccb1a138 100755
--- a/bin/wally-tool-chain-install.sh
+++ b/bin/wally-tool-chain-install.sh
@@ -137,6 +137,27 @@ sudo make install
 # package manager. Sail has so many dependencies that it can be difficult to install.
 # This script works for Ubuntu.
 
+# Alex Solomatnikov found these commands worked to build Sail for Centos 8 on 1/12/24
+#sudo su -
+#dnf install ocaml.x86_64
+#pip3 install z3-solver
+#wget https://raw.githubusercontent.com/ocaml/opam/master/shell/install.sh
+#sh install.sh
+#opam init
+#exit
+#ocaml -version
+#opam switch create 5.1.0
+#eval $(opam config env)
+#git clone --recurse-submodules git@github.com:riscv/sail-riscv.git
+#cd sail-riscv
+#make
+#ARCH=RV32 make
+#ARCH=RV64 make
+#git log -1
+#cp -p c_emulator/riscv_sim_RV* /tools/sail-riscv/d7a3d8012fd579f40e53a29569141d72dd5e0c32/bin/.
+
+
+# This was an earlier attemp to prepare to install Sail on RedHat 8
 # Do these commands only for RedHat / Rocky 8 to build from source.
 #cd $RISCV
 #git clone https://github.com/Z3Prover/z3.git