diff -r f38c93f2a771 -r 3b50e73628fd src/arch/x86/SConscript
--- a/src/arch/x86/SConscript	Sun Aug 22 18:30:25 2010 -0700
+++ b/src/arch/x86/SConscript	Sun Aug 22 18:32:48 2010 -0700
@@ -59,6 +59,7 @@
     Source('predecoder_tables.cc')
     Source('remote_gdb.cc')
     Source('tlb.cc')
+    Source('types.cc')
     Source('utility.cc')
 
     SimObject('X86NativeTrace.py')
diff -r f38c93f2a771 -r 3b50e73628fd src/arch/x86/types.hh
--- a/src/arch/x86/types.hh	Sun Aug 22 18:30:25 2010 -0700
+++ b/src/arch/x86/types.hh	Sun Aug 22 18:32:48 2010 -0700
@@ -45,6 +45,7 @@
 #include "base/bitunion.hh"
 #include "base/cprintf.hh"
 #include "base/types.hh"
+#include "sim/serialize.hh"
 
 namespace X86ISA
 {
@@ -224,4 +225,15 @@
     };
 };
 
+// These two functions allow ExtMachInst to be used with SERIALIZE_SCALAR
+// and UNSERIALIZE_SCALAR.
+template <>
+void
+paramOut(std::ostream &os, const std::string &name,
+         const X86ISA::ExtMachInst &machInst);
+template <>
+void
+paramIn(Checkpoint *cp, const std::string &section,
+        const std::string &name, X86ISA::ExtMachInst &machInst);
+
 #endif // __ARCH_X86_TYPES_HH__
diff -r f38c93f2a771 -r 3b50e73628fd src/arch/x86/types.cc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/arch/x86/types.cc	Sun Aug 22 18:32:48 2010 -0700
@@ -0,0 +1,107 @@
+/*
+ * Copyright (c) 2010 Gabe Black
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Gabe Black
+ */
+
+#include "arch/x86/types.hh"
+#include "sim/serialize.hh"
+
+using namespace X86ISA;
+using namespace std;
+
+template <>
+void
+paramOut(ostream &os, const string &name, ExtMachInst const &machInst)
+{
+    // Prefixes
+    paramOut(os, name + ".legacy", (uint8_t)machInst.legacy);
+    paramOut(os, name + ".rex", (uint8_t)machInst.rex);
+
+    // Opcode
+    paramOut(os, name + ".opcode.num", machInst.opcode.num);
+    paramOut(os, name + ".opcode.prefixA", machInst.opcode.prefixA);
+    paramOut(os, name + ".opcode.prefixB", machInst.opcode.prefixB);
+    paramOut(os, name + ".opcode.op", (uint8_t)machInst.opcode.op);
+
+    // Modifier bytes
+    paramOut(os, name + ".modRM", (uint8_t)machInst.modRM);
+    paramOut(os, name + ".sib", (uint8_t)machInst.sib);
+
+    // Immediate fields
+    paramOut(os, name + ".immediate", machInst.immediate);
+    paramOut(os, name + ".displacement", machInst.displacement);
+
+    // Sizes
+    paramOut(os, name + ".opSize", machInst.opSize);
+    paramOut(os, name + ".addrSize", machInst.addrSize);
+    paramOut(os, name + ".stackSize", machInst.stackSize);
+    paramOut(os, name + ".dispSize", machInst.dispSize);
+
+    // Mode
+    paramOut(os, name + ".mode", (uint8_t)machInst.mode);
+}
+
+template <>
+void
+paramIn(Checkpoint *cp, const string &section,
+        const string &name, ExtMachInst &machInst)
+{
+    uint8_t temp8;
+    // Prefixes
+    paramIn(cp, section, name + ".legacy", temp8);
+    machInst.legacy = temp8;
+    paramIn(cp, section, name + ".rex", temp8);
+    machInst.rex = temp8;
+
+    // Opcode
+    paramIn(cp, section, name + ".opcode.num", machInst.opcode.num);
+    paramIn(cp, section, name + ".opcode.prefixA", machInst.opcode.prefixA);
+    paramIn(cp, section, name + ".opcode.prefixB", machInst.opcode.prefixB);
+    paramIn(cp, section, name + ".opcode.op", temp8);
+    machInst.opcode.op = temp8;
+
+    // Modifier bytes
+    paramIn(cp, section, name + ".modRM", temp8);
+    machInst.modRM = temp8;
+    paramIn(cp, section, name + ".sib", temp8);
+    machInst.sib = temp8;;
+
+    // Immediate fields
+    paramIn(cp, section, name + ".immediate", machInst.immediate);
+    paramIn(cp, section, name + ".displacement", machInst.displacement);
+
+    // Sizes
+    paramIn(cp, section, name + ".opSize", machInst.opSize);
+    paramIn(cp, section, name + ".addrSize", machInst.addrSize);
+    paramIn(cp, section, name + ".stackSize", machInst.stackSize);
+    paramIn(cp, section, name + ".dispSize", machInst.dispSize);
+
+    // Mode
+    paramIn(cp, section, name + ".mode", temp8);
+    machInst.mode = temp8;
+}