diff --git a/src/arch/x86/SConscript b/src/arch/x86/SConscript
index 6d65fbb57..3a94866bb 100644
--- a/src/arch/x86/SConscript
+++ b/src/arch/x86/SConscript
@@ -178,6 +178,7 @@ if env['TARGET_ISA'] == 'x86':
         'general_purpose/string/store_string.py',
         'general_purpose/system_calls.py',
         'system/__init__.py',
+        'system/halt.py',
         'system/undefined_operation.py',
         'system/msrs.py',
         'simd128/__init__.py',
diff --git a/src/arch/x86/isa/decoder/one_byte_opcodes.isa b/src/arch/x86/isa/decoder/one_byte_opcodes.isa
index 538bb4c32..ac714b3ff 100644
--- a/src/arch/x86/isa/decoder/one_byte_opcodes.isa
+++ b/src/arch/x86/isa/decoder/one_byte_opcodes.isa
@@ -504,7 +504,7 @@
                 {{"Tried to execute the repne prefix!"}});
             0x3: M5InternalError::error(
                 {{"Tried to execute the rep/repe prefix!"}});
-            0x4: WarnUnimpl::hlt();
+            0x4: HLT();
             0x5: CMC();
             //0x6: group3_Eb();
             0x6: decode MODRM_REG {
diff --git a/src/arch/x86/isa/insts/system/__init__.py b/src/arch/x86/isa/insts/system/__init__.py
index 6d4b3f3d1..422438b1c 100644
--- a/src/arch/x86/isa/insts/system/__init__.py
+++ b/src/arch/x86/isa/insts/system/__init__.py
@@ -53,7 +53,8 @@
 #
 # Authors: Gabe Black
 
-categories = ["undefined_operation",
+categories = ["halt",
+              "undefined_operation",
               "msrs"]
 
 microcode = ""
diff --git a/src/arch/x86/isa/insts/system/halt.py b/src/arch/x86/isa/insts/system/halt.py
new file mode 100644
index 000000000..d1284e81b
--- /dev/null
+++ b/src/arch/x86/isa/insts/system/halt.py
@@ -0,0 +1,60 @@
+# Copyright (c) 2007 The Hewlett-Packard Development Company
+# All rights reserved.
+#
+# Redistribution and use of this software in source and binary forms,
+# with or without modification, are permitted provided that the
+# following conditions are met:
+#
+# The software must be used only for Non-Commercial Use which means any
+# use which is NOT directed to receiving any direct monetary
+# compensation for, or commercial advantage from such use.  Illustrative
+# examples of non-commercial use are academic research, personal study,
+# teaching, education and corporate research & development.
+# Illustrative examples of commercial use are distributing products for
+# commercial advantage and providing services using the software for
+# commercial advantage.
+#
+# If you wish to use this software or functionality therein that may be
+# covered by patents for commercial use, please contact:
+#     Director of Intellectual Property Licensing
+#     Office of Strategy and Technology
+#     Hewlett-Packard Company
+#     1501 Page Mill Road
+#     Palo Alto, California  94304
+#
+# 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 HOLDER(s), HEWLETT-PACKARD COMPANY, nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.  No right of
+# sublicense is granted herewith.  Derivatives of the software and
+# output created using the software may be prepared, but only for
+# Non-Commercial Uses.  Derivatives of the software may be shared with
+# others provided: (i) the others agree to abide by the list of
+# conditions herein which includes the Non-Commercial Use restrictions;
+# and (ii) such Derivatives of the software include the above copyright
+# notice to acknowledge the contribution from this software where
+# applicable, this list of conditions and the disclaimer below.
+#
+# 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
+
+microcode = '''
+def macroop HLT {
+    halt
+};
+'''
diff --git a/src/arch/x86/isa/microops/specop.isa b/src/arch/x86/isa/microops/specop.isa
index dfc7f3e8b..3ca59f033 100644
--- a/src/arch/x86/isa/microops/specop.isa
+++ b/src/arch/x86/isa/microops/specop.isa
@@ -135,7 +135,7 @@ output exec {{
     MicroHalt::execute(%(CPU_exec_context)s *xc,
             Trace::InstRecord * traceData) const
     {
-        xc->suspend();
+        xc->tcBase()->suspend();
         return NoFault;
     }
 }};
@@ -244,7 +244,7 @@ let {{
             pass
 
         def getAllocator(self, *microFlags):
-            return "new MicroHalt(machInst, mnemonic %(flags)s)" % \
+            return "new MicroHalt(machInst, mnemonic %s)" % \
                     self.microFlagsText(microFlags)
 
     microopClasses["halt"] = Halt