From: Ali Saidi <Ali.Saidi@ARM.com>
Date: Fri, 15 Feb 2013 22:40:08 +0000 (-0500)
Subject: cpu: fix case with o3 cpu blocking and unblocking decode in cycle
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=7ae06a3b3bb6c5438cd9cac7f1fe5f8cdb65e07d;p=gem5.git

cpu: fix case with o3 cpu blocking and unblocking decode in cycle

Fix a case in the O3 CPU where the decode stage blocks and unblocks in a
single cycle sending both signals to fetch which causes an assert or worse.
The previous check could never work before since the status was set to Blocked
before a test for the status being Unblocking was executed.
---

diff --git a/src/cpu/o3/decode_impl.hh b/src/cpu/o3/decode_impl.hh
index cd226017f..f87ec0bfa 100644
--- a/src/cpu/o3/decode_impl.hh
+++ b/src/cpu/o3/decode_impl.hh
@@ -241,7 +241,9 @@ DefaultDecode<Impl>::block(ThreadID tid)
         // Set the status to Blocked.
         decodeStatus[tid] = Blocked;
 
-        if (decodeStatus[tid] != Unblocking) {
+        if (toFetch->decodeUnblock[tid]) {
+            toFetch->decodeUnblock[tid] = false;
+        } else {
             toFetch->decodeBlock[tid] = true;
             wroteToTimeBuffer = true;
         }