Make the predecoder an object with it's own switched header file. Start adding predecoding functionality to x86.

src/arch/SConscript:
src/arch/alpha/utility.hh:
src/arch/mips/utility.hh:
src/arch/sparc/utility.hh:
src/cpu/base.hh:
src/cpu/o3/fetch.hh:
src/cpu/o3/fetch_impl.hh:
src/cpu/simple/atomic.cc:
src/cpu/simple/base.cc:
src/cpu/simple/base.hh:
src/cpu/static_inst.hh:
src/arch/alpha/predecoder.hh:
src/arch/mips/predecoder.hh:
src/arch/sparc/predecoder.hh:
    Make the predecoder an object with it's own switched header file.

--HG--
extra : convert_revision : 77206e29089130e86b97164c30022a062699ba86

3 files changed, 41 insertions, 23 deletions

diff --git a/src/cpu/simple/atomic.cc b/src/cpu/simple/atomic.cc
index df7e780e6..0361db012 100644
--- a/src/cpu/simple/atomic.cc
+++ b/src/cpu/simple/atomic.cc
@@ -500,17 +500,28 @@ AtomicSimpleCPU::tick()
         Fault fault = setupFetchRequest(ifetch_req);
 
         if (fault == NoFault) {
-            ifetch_pkt->reinitFromRequest();
+            Tick icache_latency = 0;
+            bool icache_access = false;
+            dcache_access = false; // assume no dcache access
 
-            Tick icache_latency = icachePort.sendAtomic(ifetch_pkt);
-            // ifetch_req is initialized to read the instruction directly
-            // into the CPU object's inst field.
+            //Fetch more instruction memory if necessary
+            if(predecoder.needMoreBytes())
+            {
+                icache_access = true;
+                ifetch_pkt->reinitFromRequest();
+
+                icache_latency = icachePort.sendAtomic(ifetch_pkt);
+                // ifetch_req is initialized to read the instruction directly
+                // into the CPU object's inst field.
+            }
 
-            dcache_access = false; // assume no dcache access
             preExecute();
 
-            fault = curStaticInst->execute(this, traceData);
-            postExecute();
+            if(curStaticInst)
+            {
+                fault = curStaticInst->execute(this, traceData);
+                postExecute();
+            }
 
             // @todo remove me after debugging with legion done
             if (curStaticInst && (!curStaticInst->isMicroOp() ||
@@ -518,7 +529,8 @@ AtomicSimpleCPU::tick()
                 instCnt++;
 
             if (simulate_stalls) {
-                Tick icache_stall = icache_latency - cycles(1);
+                Tick icache_stall =
+                    icache_access ? icache_latency - cycles(1) : 0;
                 Tick dcache_stall =
                     dcache_access ? dcache_latency - cycles(1) : 0;
                 Tick stall_cycles = (icache_stall + dcache_stall) / cycles(1);
@@ -529,8 +541,8 @@ AtomicSimpleCPU::tick()
             }
 
         }
-
-        advancePC(fault);
+        if(predecoder.needMoreBytes())
+            advancePC(fault);
     }
 
     if (_status != Idle)
diff --git a/src/cpu/simple/base.cc b/src/cpu/simple/base.cc
index c27be02bf..2ad328542 100644
--- a/src/cpu/simple/base.cc
+++ b/src/cpu/simple/base.cc
@@ -70,7 +70,7 @@ using namespace std;
 using namespace TheISA;
 
 BaseSimpleCPU::BaseSimpleCPU(Params *p)
-    : BaseCPU(p), thread(NULL)
+    : BaseCPU(p), thread(NULL), predecoder(NULL)
 {
 #if FULL_SYSTEM
     thread = new SimpleThread(this, 0, p->system, p->itb, p->dtb);
@@ -370,11 +370,16 @@ BaseSimpleCPU::preExecute()
         StaticInstPtr instPtr = NULL;
 
         //Predecode, ie bundle up an ExtMachInst
-        unsigned int result =
-            predecode(extMachInst, thread->readPC(), inst, thread->getTC());
+        //This should go away once the constructor can be set up properly
+        predecoder.setTC(thread->getTC());
+        //If more fetch data is needed, pass it in.
+        if(predecoder.needMoreBytes())
+            predecoder.moreBytes(thread->readPC(), 0, inst);
+        else
+            predecoder.process();
         //If an instruction is ready, decode it
-        if (result & ExtMIReady)
-            instPtr = StaticInst::decode(extMachInst);
+        if (predecoder.extMachInstReady())
+            instPtr = StaticInst::decode(predecoder.getExtMachInst());
 
         //If we decoded an instruction and it's microcoded, start pulling
         //out micro ops
@@ -446,9 +451,9 @@ BaseSimpleCPU::advancePC(Fault fault)
         fault->invoke(tc);
         thread->setMicroPC(0);
         thread->setNextMicroPC(1);
-    } else {
+    } else if (predecoder.needMoreBytes()) {
         //If we're at the last micro op for this instruction
-        if (curStaticInst->isLastMicroOp()) {
+        if (curStaticInst && curStaticInst->isLastMicroOp()) {
             //We should be working with a macro op
             assert(curMacroStaticInst);
             //Close out this macro op, and clean up the
@@ -467,13 +472,9 @@ BaseSimpleCPU::advancePC(Fault fault)
         } else {
             // go to the next instruction
             thread->setPC(thread->readNextPC());
-#if ISA_HAS_DELAY_SLOT
             thread->setNextPC(thread->readNextNPC());
             thread->setNextNPC(thread->readNextNPC() + sizeof(MachInst));
             assert(thread->readNextPC() != thread->readNextNPC());
-#else
-            thread->setNextPC(thread->readNextPC() + sizeof(MachInst));
-#endif
         }
     }
 
diff --git a/src/cpu/simple/base.hh b/src/cpu/simple/base.hh
index 10787c474..a7686bbb1 100644
--- a/src/cpu/simple/base.hh
+++ b/src/cpu/simple/base.hh
@@ -33,6 +33,7 @@
 #ifndef __CPU_SIMPLE_BASE_HH__
 #define __CPU_SIMPLE_BASE_HH__
 
+#include "arch/predecoder.hh"
 #include "base/statistics.hh"
 #include "config/full_system.hh"
 #include "cpu/base.hh"
@@ -63,6 +64,10 @@ class Process;
 class RemoteGDB;
 class GDBListener;
 
+namespace TheISA
+{
+    class Predecoder;
+}
 class ThreadContext;
 class Checkpoint;
 
@@ -123,8 +128,8 @@ class BaseSimpleCPU : public BaseCPU
     // current instruction
     TheISA::MachInst inst;
 
-    // current extended machine instruction
-    TheISA::ExtMachInst extMachInst;
+    // The predecoder
+    TheISA::Predecoder predecoder;
 
     // Static data storage
     TheISA::LargestRead dataReg;