x86: fix debug trace output for mwait

When running with the Exec flag, the mwait instruction attempted
to print out its source registers, which were never actually
initialized. This led to sporadic assertion failures when the
value stored there was invalid.

Committed by: Nilay Vaish <nilay@cs.wisc.edu>

diff --git a/src/arch/x86/isa/formats/monitor_mwait.isa b/src/arch/x86/isa/formats/monitor_mwait.isa
index 493b7c58a3d7cdb51a3026bde65a5475322b7596..b26c1f26700fb075f72df70dc05c0422740a8f69 100644 (file)
--- a/src/arch/x86/isa/formats/monitor_mwait.isa
+++ b/src/arch/x86/isa/formats/monitor_mwait.isa
@@ -112,9 +112,9 @@ output decoder {{
     {
         std::stringstream response;
 
+        // Although mwait could take hints from eax and ecx, the _srcRegIdx
+        // is not set, and thus should not be printed here
         printMnemonic(response, mnemonic);
-        ccprintf(response, " ");
-        printReg(response, _srcRegIdx[0], machInst.opSize);
         return response.str();
     }
 }};