diff -r f348cf78072c src/arch/mips/isa/decoder.isa
--- a/src/arch/mips/isa/decoder.isa	Thu Jan 12 10:15:00 2012 -0500
+++ b/src/arch/mips/isa/decoder.isa	Tue Jan 17 00:55:12 2012 +0800
@@ -649,7 +649,8 @@
                         StatusReg status = Status;
                         ConfigReg config = Config;
                         SRSCtlReg srsCtl = SRSCtl;
-                        DPRINTF(MipsPRA,"Restoring PC - %x\n",EPC);
+                        // TODO: here met a compiling error: NPC may be used uninitialized
+                        DPRINTF(MipsPRA,"Restoring PC - %x, NPC=%x, NNPC=%x\n",EPC, NPC, NNPC);
                         if (status.erl == 1) {
                             status.erl = 0;
                             NPC = ErrorEPC;
@@ -777,6 +778,8 @@
                             SP = 1;
                         }
                         Ptr->insertAt(newEntry, Index & 0x7FFFFFFF, SP);
+                        Ptr = xc->tcBase()->getDTBPtr();
+                        Ptr->insertAt(newEntry, Index & 0x7FFFFFFF, SP);
                     }});
                     0x06: tlbwr({{
                         //Create PTE
@@ -841,7 +844,13 @@
                             bits(pageGrain, pageGrain.esp) == 1) {
                             SP = 1;
                         }
-                        Ptr->insertAt(newEntry, Random, SP);
+
+                        // TODO: generate a real random number here
+                        static int random = 0;
+                        random = (random + 1) % 64;
+                        Ptr->insertAt(newEntry, random, SP);
+                        Ptr = xc->tcBase()->getDTBPtr();
+                        Ptr->insertAt(newEntry, random, SP);
                     }});
 
                     0x08: tlbp({{
@@ -867,9 +876,10 @@
                         }
                     }});
                 }
-                format CP0Unimpl {
-                    0x20: wait();
-                }
+                0x20: BasicOp::wait({{
+                    // TODO: check the function of wait instruction
+                    //fault = new CoprocessorUnusableFault(0);
+                }}, IsMemBarrier);
                 default: CP0Unimpl::unknown();
             }
         }
@@ -2430,11 +2440,14 @@
                         }
                     }
                 }
-                0x3: decode OP default FailUnimpl::rdhwr() {
+                0x3: decode OP {
                     0x0: decode FULL_SYSTEM {
                         0: decode RD {
                             29: BasicOp::rdhwr_se({{ Rt = TpValue; }});
                         }
+                        1: CP0Control::rdhwr({{
+                            fault = new CoprocessorUnusableFault(0);
+                        }});
                     }
                 }
             }