From 0bfdf342da40842a05351d53a384db4a8ff88bf5 Mon Sep 17 00:00:00 2001
From: Korey Sewell <ksewell@umich.edu>
Date: Sun, 19 Jun 2011 21:43:40 -0400
Subject: [PATCH] inorder: explicit fault check Before graduating an
 instruction, explicitly check fault by making the fault check it's own
 separate command that can be put on an instruction schedule.

---
 src/cpu/inorder/cpu.cc                       |  4 ++-
 src/cpu/inorder/resources/graduation_unit.cc | 28 +++++++++++++-------
 src/cpu/inorder/resources/graduation_unit.hh |  1 +
 3 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/src/cpu/inorder/cpu.cc b/src/cpu/inorder/cpu.cc
index 834e591f8..232bf8279 100644
--- a/src/cpu/inorder/cpu.cc
+++ b/src/cpu/inorder/cpu.cc
@@ -517,7 +517,7 @@ InOrderCPU::createBackEndSked(DynInstPtr inst)
         }
     }
 
-    W.needs(Grad, GraduationUnit::GraduateInst);
+    W.needs(Grad, GraduationUnit::CheckFault);
 
     for (int idx=0; idx < inst->numDestRegs(); idx++) {
         W.needs(RegManager, UseDefUnit::WriteDestReg, idx);
@@ -526,6 +526,8 @@ InOrderCPU::createBackEndSked(DynInstPtr inst)
     if (inst->isControl())
         W.needs(BPred, BranchPredictor::UpdatePredictor);
 
+    W.needs(Grad, GraduationUnit::GraduateInst);
+
     // Insert Back Schedule into our cache of
     // resource schedules
     addToSkedCache(inst, res_sked);
diff --git a/src/cpu/inorder/resources/graduation_unit.cc b/src/cpu/inorder/resources/graduation_unit.cc
index 4f796e933..617ef14f6 100644
--- a/src/cpu/inorder/resources/graduation_unit.cc
+++ b/src/cpu/inorder/resources/graduation_unit.cc
@@ -56,6 +56,24 @@ GraduationUnit::execute(int slot_num)
 
     switch (grad_req->cmd)
     {
+      case CheckFault:
+        {
+            // Handle Any Faults Before Graduating Instruction
+            if (inst->fault != NoFault) {
+                DPRINTF(InOrderGraduation, "[tid:%i]: [sn:%i]: fault %s found for %s\n",
+                        tid, inst->seqNum, inst->fault->name(),
+                        inst->instName());
+                squashThenTrap(stage_num, inst);
+                grad_req->done(false);
+                return;
+            }
+
+            DPRINTF(InOrderGraduation, "[tid:%i] [sn:%i]: No fault found for %s\n",
+                    tid, inst->seqNum, inst->instName());
+            grad_req->done();
+        }
+        break;
+
       case GraduateInst:
         {
             if (lastNonSpecTick == curTick()) {
@@ -65,16 +83,6 @@ GraduationUnit::execute(int slot_num)
                 return;
             }
 
-            // Handle Any Faults Before Graduating Instruction
-            if (inst->fault != NoFault) {
-                DPRINTF(Fault, "[sn:%i]: fault %s found for %s\n",
-                        inst->seqNum, inst->fault->name(),
-                        inst->instName());
-                squashThenTrap(stage_num, inst);
-                grad_req->done(false);
-                return;
-            }
-
             DPRINTF(InOrderGraduation,
                     "[tid:%i]:[sn:%i]: Graduating instruction %s.\n",
                     tid, inst->seqNum, inst->staticInst->disassemble(inst->instAddr()));
diff --git a/src/cpu/inorder/resources/graduation_unit.hh b/src/cpu/inorder/resources/graduation_unit.hh
index 043e375e7..01abae85b 100644
--- a/src/cpu/inorder/resources/graduation_unit.hh
+++ b/src/cpu/inorder/resources/graduation_unit.hh
@@ -46,6 +46,7 @@ class GraduationUnit : public Resource {
     typedef ThePipeline::DynInstPtr DynInstPtr;
 
     enum Command {
+        CheckFault,
         GraduateInst
     };