X86: Recognize and handle the lock legacy prefix.

1 files changed, 29 insertions, 23 deletions

diff --git a/src/arch/x86/isa/decoder/decoder.isa b/src/arch/x86/isa/decoder/decoder.isa
index 20f31f882..dcf6ce089 100644
--- a/src/arch/x86/isa/decoder/decoder.isa
+++ b/src/arch/x86/isa/decoder/decoder.isa
@@ -58,32 +58,38 @@
 // The actual decoder specification
 //
 
-decode OPCODE_NUM default Unknown::unknown()
+decode LEGACY_LOCK default Unknown::unknown()
 {
-    0x0: M5InternalError::error(
-        {{"Saw an ExtMachInst with zero opcode bytes!"}});
-    //1 byte opcodes
-    ##include "one_byte_opcodes.isa"
-    //2 byte opcodes
-    ##include "two_byte_opcodes.isa"
-    //3 byte opcodes
-    0x3: decode OPCODE_PREFIXA {
-        0xF0: decode OPCODE_PREFIXB {
-            //We don't handle these properly in the predecoder yet, so there's
-            //no reason to implement them for now.
-            0x38: decode OPCODE_OP {
-                default: FailUnimpl::sseThreeEight();
-            }
-            0x3A: decode OPCODE_OP {
-                default: FailUnimpl::sseThreeA();
-            }
-            0xF0: decode OPCODE_OP {
-                default: FailUnimpl::threednow();
+    //No lock prefix
+    0x0: decode OPCODE_NUM default Unknown::unknown()
+    {
+        0x0: M5InternalError::error(
+            {{"Saw an ExtMachInst with zero opcode bytes!"}});
+        //1 byte opcodes
+        ##include "one_byte_opcodes.isa"
+        //2 byte opcodes
+        ##include "two_byte_opcodes.isa"
+        //3 byte opcodes
+        0x3: decode OPCODE_PREFIXA {
+            0xF0: decode OPCODE_PREFIXB {
+                //We don't handle these properly in the predecoder yet, so
+                //there's no reason to implement them for now.
+                0x38: decode OPCODE_OP {
+                    default: FailUnimpl::sseThreeEight();
+                }
+                0x3A: decode OPCODE_OP {
+                    default: FailUnimpl::sseThreeA();
+                }
+                0xF0: decode OPCODE_OP {
+                    default: FailUnimpl::threednow();
+                }
+                default: M5InternalError::error(
+                    {{"Unexpected second opcode byte in three byte opcode!"}});
             }
             default: M5InternalError::error(
-                {{"Unexpected second opcode byte in three byte opcode!"}});
+                {{"Unexpected first opcode byte in three byte opcode!"}});
         }
-        default: M5InternalError::error(
-            {{"Unexpected first opcode byte in three byte opcode!"}});
     }
+    //Lock prefix
+    ##include "locked_opcodes.isa"
 }