From 78cad5bbcc87f39d4aef6e9171a8cc6ebf32c197 Mon Sep 17 00:00:00 2001
From: James Clarke <jrtc27@jrtc27.com>
Date: Sat, 2 Nov 2019 20:38:35 +0000
Subject: [PATCH] Fix BTB entry aliasing with C extension

---
 src_Core/RISCY_OOO/procs/lib/Btb.bsv | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src_Core/RISCY_OOO/procs/lib/Btb.bsv b/src_Core/RISCY_OOO/procs/lib/Btb.bsv
index bd035a7..713013f 100644
--- a/src_Core/RISCY_OOO/procs/lib/Btb.bsv
+++ b/src_Core/RISCY_OOO/procs/lib/Btb.bsv
@@ -39,9 +39,10 @@ interface NextAddrPred;
 endinterface
 
 // Local BTB Typedefs
+typedef 1 PcLsbsIgnore;
 typedef 256 BtbEntries; // 4KB BTB
 typedef Bit#(TLog#(BtbEntries)) BtbIndex;
-typedef Bit#(TSub#(TSub#(AddrSz, TLog#(BtbEntries)), 2)) BtbTag;
+typedef Bit#(TSub#(TSub#(AddrSz, TLog#(BtbEntries)), PcLsbsIgnore)) BtbTag;
 
 typedef struct {
     Addr pc;
@@ -65,7 +66,7 @@ module mkBtb(NextAddrPred);
     Bool flushDone = True;
 `endif
 
-    function BtbIndex getIndex(Addr pc) = truncate(pc >> 2);
+    function BtbIndex getIndex(Addr pc) = truncate(pc >> valueof(PcLsbsIgnore));
     function BtbTag getTag(Addr pc) = truncateLSB(pc);
 
     // no flush, accept update