4 files changed, 220 insertions, 2 deletions
diff --git a/src/arch/alpha/predecoder.hh b/src/arch/alpha/predecoder.hh
index 4e89f53a6..650f2bfa2 100644
--- a/src/arch/alpha/predecoder.hh
+++ b/src/arch/alpha/predecoder.hh
@@ -33,6 +33,7 @@
 
 #include "arch/alpha/types.hh"
 #include "base/misc.hh"
+#include "config/full_system.hh"
 #include "sim/host.hh"
 
 class ThreadContext;
diff --git a/src/arch/sparc/predecoder.hh b/src/arch/sparc/predecoder.hh
index 71b14b020..4a8c9dc4a 100644
--- a/src/arch/sparc/predecoder.hh
+++ b/src/arch/sparc/predecoder.hh
@@ -33,6 +33,7 @@
 
 #include "arch/sparc/types.hh"
 #include "base/misc.hh"
+#include "cpu/thread_context.hh"
 #include "sim/host.hh"
 
 class ThreadContext;
diff --git a/src/base/bitfield.hh b/src/base/bitfield.hh
index 79dbcc86c..ff816286f 100644
--- a/src/base/bitfield.hh
+++ b/src/base/bitfield.hh
@@ -130,6 +130,216 @@ findMsbSet(uint64_t val) {
     return msb;
 }
 
+//	The following implements the BitUnion system of defining bitfields
+//on top of an underlying class. This is done through the pervasive use of
+//both named and unnamed unions which all contain the same actual storage.
+//Since they're unioned with each other, all of these storage locations
+//overlap. This allows all of the bitfields to manipulate the same data
+//without having to have access to each other. More details are provided with the
+//individual components.
 
+//This namespace is for classes which implement the backend of the BitUnion
+//stuff. Don't use any of these directly, except for the Bitfield classes in
+//the *BitfieldTypes class(es).
+namespace BitfieldBackend
+{
+    //A base class for all bitfields. It instantiates the actual storage,
+    //and provides getBits and setBits functions for manipulating it. The
+    //Data template parameter is type of the underlying storage.
+    template<class Data>
+    class BitfieldBase
+    {
+      protected:
+        Data __data;
+
+        //This function returns a range of bits from the underlying storage.
+        //It relies on the "bits" function above. It's the user's
+        //responsibility to make sure that there is a properly overloaded
+        //version of this function for whatever type they want to overlay.
+        inline uint64_t
+        getBits(int first, int last)
+        {
+            return bits(__data, first, last);
+        }
+
+        //Similar to the above, but for settings bits with replaceBits.
+        inline void
+        setBits(int first, int last, uint64_t val)
+        {
+            replaceBits(__data, first, last, val);
+        }
+    };
+
+    //This class contains all the "regular" bitfield classes. It is inherited
+    //by all BitUnions which give them access to those types.
+    template<class Type>
+    class RegularBitfieldTypes
+    {
+      protected:
+        //This class implements ordinary bitfields, that is a span of bits
+        //who's msb is "first", and who's lsb is "last".
+        template<int first, int last=first>
+        class Bitfield : public BitfieldBase<Type>
+        {
+          public:
+            operator const Type ()
+            {
+                return this->getBits(first, last);
+            }
+
+            const Type
+            operator=(const Type & _data)
+            {
+                this->setBits(first, last, _data);
+                return _data;
+            }
+        };
+
+        //A class which specializes the above so that it can only be read
+        //from. This is accomplished explicitly making sure the assignment
+        //operator is blocked. The conversion operator is carried through
+        //inheritance. This will unfortunately need to be copied into each
+        //bitfield type due to limitations with how templates work
+        template<int first, int last=first>
+        class BitfieldRO : public Bitfield<first, last>
+        {
+          private:
+            const Type
+            operator=(const Type & _data);
+        };
+
+        //Similar to the above, but only allows writing.
+        template<int first, int last=first>
+        class BitfieldWO : public Bitfield<first, last>
+        {
+          private:
+            operator const Type ();
+
+          public:
+            const Type operator=(const Type & _data)
+            {
+                *((Bitfield<first, last> *)this) = _data;
+                return _data;
+            }
+        };
+    };
+
+    template<class Type>
+    class BitfieldTypes : public RegularBitfieldTypes<Type>
+    {};
+
+    //When a BitUnion is set up, an underlying class is created which holds
+    //the actual union. This class then inherits from it, and provids the
+    //implementations for various operators. Setting things up this way
+    //prevents having to redefine these functions in every different BitUnion
+    //type. More operators could be implemented in the future, as the need
+    //arises.
+    template <class Type, class Base>
+    class BitUnionOperators : public Base
+    {
+      public:
+        operator const Type ()
+        {
+            return Base::__data;
+        }
+
+        const Type
+        operator=(const Type & _data)
+        {
+            Base::__data = _data;
+        }
+
+        bool
+        operator<(const Base & base)
+        {
+            return Base::__data < base.__data;
+        }
+
+        bool
+        operator==(const Base & base)
+        {
+            return Base::__data == base.__data;
+        }
+    };
+}
+
+//This macro is a backend for other macros that specialize it slightly.
+//First, it creates/extends a namespace "BitfieldUnderlyingClasses" and
+//sticks the class which has the actual union in it, which
+//BitfieldOperators above inherits from. Putting these classes in a special
+//namespace ensures that there will be no collisions with other names as long
+//as the BitUnion names themselves are all distinct and nothing else uses
+//the BitfieldUnderlyingClasses namespace, which is unlikely. The class itself
+//creates a typedef of the "type" parameter called __DataType. This allows
+//the type to propagate outside of the macro itself in a controlled way.
+//Finally, the base storage is defined which BitfieldOperators will refer to
+//in the operators it defines. This macro is intended to be followed by
+//bitfield definitions which will end up inside it's union. As explained
+//above, these is overlayed the __data member in its entirety by each of the
+//bitfields which are defined in the union, creating shared storage with no
+//overhead.
+#define __BitUnion(type, name) \
+    namespace BitfieldUnderlyingClasses \
+    { \
+        class name; \
+    } \
+    class BitfieldUnderlyingClasses::name : \
+        public BitfieldBackend::BitfieldTypes<type> \
+    { \
+      public: \
+        typedef type __DataType; \
+        union { \
+            type __data;\
+
+//This closes off the class and union started by the above macro. It is
+//followed by a typedef which makes "name" refer to a BitfieldOperator
+//class inheriting from the class and union just defined, which completes
+//building up the type for the user.
+#define EndBitUnion(name) \
+        }; \
+    }; \
+    typedef BitfieldBackend::BitUnionOperators< \
+        BitfieldUnderlyingClasses::name::__DataType, \
+        BitfieldUnderlyingClasses::name> name;
+
+//This sets up a bitfield which has other bitfields nested inside of it. The
+//__data member functions like the "underlying storage" of the top level
+//BitUnion. Like everything else, it overlays with the top level storage, so
+//making it a regular bitfield type makes the entire thing function as a
+//regular bitfield when referred to by itself.
+#define __SubBitUnion(fieldType, first, last, name) \
+    class : public BitfieldBackend::BitfieldTypes<__DataType> \
+    { \
+      public: \
+        union { \
+            fieldType<first, last> __data;
+
+//This closes off the union created above and gives it a name. Unlike the top
+//level BitUnion, we're interested in creating an object instead of a type.
+//The operators are defined in the macro itself instead of a class for
+//technical reasons. If someone determines a way to move them to one, please
+//do so.
+#define EndSubBitUnion(name) \
+        }; \
+        inline operator const __DataType () \
+        { return __data; } \
+        \
+        inline const __DataType operator = (const __DataType & _data) \
+        { __data = _data; } \
+    } name;
+
+//Regular bitfields
+//These define macros for read/write regular bitfield based subbitfields.
+#define SubBitUnion(name, first, last) \
+    __SubBitUnion(Bitfield, first, last, name)
+
+//Use this to define an arbitrary type overlayed with bitfields.
+#define BitUnion(type, name) __BitUnion(type, name)
+
+//Use this to define conveniently sized values overlayed with bitfields.
+#define BitUnion64(name) __BitUnion(uint64_t, name)
+#define BitUnion32(name) __BitUnion(uint32_t, name)
+#define BitUnion16(name) __BitUnion(uint16_t, name)
+#define BitUnion8(name) __BitUnion(uint8_t, name)
 
 #endif // __BASE_BITFIELD_HH__
diff --git a/src/cpu/exetrace.cc b/src/cpu/exetrace.cc
index 1799b46c5..c568b1439 100644
--- a/src/cpu/exetrace.cc
+++ b/src/cpu/exetrace.cc
@@ -37,6 +37,7 @@
 #include <sys/ipc.h>
 #include <sys/shm.h>
 
+#include "arch/predecoder.hh"
 #include "arch/regfile.hh"
 #include "arch/utility.hh"
 #include "base/loader/symtab.hh"
@@ -393,6 +394,7 @@ Trace::InstRecord::dump()
         outs << endl;
     }
 #if THE_ISA == SPARC_ISA && FULL_SYSTEM
+    static TheISA::Predecoder predecoder(NULL);
     // Compare
     if (IsOn(ExecLegion))
     {
@@ -647,9 +649,13 @@ Trace::InstRecord::dump()
                              << staticInst->disassemble(m5Pc, debugSymbolTable)
                              << endl;
 
+                        predecoder.setTC(thread);
+                        predecoder.moreBytes(m5Pc, 0, shared_data->instruction);
+
+                        assert(predecoder.extMachInstRead());
+
                         StaticInstPtr legionInst =
-                            StaticInst::decode(makeExtMI(shared_data->instruction,
-                                        thread));
+                            StaticInst::decode(predecoder.getExtMachInst());
                         outs << setfill(' ') << setw(15)
                              << " Legion Inst: "
                              << "0x" << setw(8) << setfill('0') << hex