x86: Add microop for fence

This patch adds a new microop for memory barrier. The microop itself does
nothing, but since it is marked as a memory barrier, the O3 CPU should flush
all the pending loads and stores before the fence to the memory system.

1 files changed, 53 insertions, 0 deletions

diff --git a/src/arch/x86/isa/microops/specop.isa b/src/arch/x86/isa/microops/specop.isa
index 52420f175..5c242e2c9 100644
--- a/src/arch/x86/isa/microops/specop.isa
+++ b/src/arch/x86/isa/microops/specop.isa
@@ -1,4 +1,5 @@
 // Copyright (c) 2007-2008 The Hewlett-Packard Development Company
+// Copyright (c) 2011 Mark D. Hill and David A. Wood
 // All rights reserved.
 //
 // The license below extends only to copyright in the software and shall
@@ -203,3 +204,55 @@ let {{
 
     microopClasses["halt"] = Halt
 }};
+
+def template MicroFenceOpDeclare {{
+    class %(class_name)s : public X86ISA::X86MicroopBase
+    {
+      public:
+        %(class_name)s(ExtMachInst _machInst,
+                const char * instMnem,
+                uint64_t setFlags);
+
+        %(BasicExecDeclare)s
+    };
+}};
+
+def template MicroFenceOpConstructor {{
+    inline %(class_name)s::%(class_name)s(
+            ExtMachInst machInst, const char * instMnem, uint64_t setFlags) :
+        %(base_class)s(machInst, "%(mnemonic)s", instMnem,
+                setFlags, %(op_class)s)
+    {
+        %(constructor)s;
+    }
+}};
+
+let {{
+    class MfenceOp(X86Microop):
+        def __init__(self):
+            self.className = "Mfence"
+            self.mnemonic = "mfence"
+            self.instFlags = "| (1ULL << StaticInst::IsMemBarrier)"
+
+        def getAllocator(self, microFlags):
+            allocString = '''
+                    (StaticInstPtr)(new %(class_name)s(machInst,
+                        macrocodeBlock, %(flags)s))
+            '''
+            allocator = allocString % {
+                "class_name" : self.className,
+                "mnemonic" : self.mnemonic,
+                "flags" : self.microFlagsText(microFlags) + self.instFlags}
+            return allocator
+
+    microopClasses["mfence"] = MfenceOp
+}};
+
+let {{
+    # Build up the all register version of this micro op
+    iop = InstObjParams("mfence", "Mfence", 'X86MicroopBase',
+            {"code" : ""})
+    header_output += MicroFenceOpDeclare.subst(iop)
+    decoder_output += MicroFenceOpConstructor.subst(iop)
+    exec_output += BasicExecute.subst(iop)
+}};