diff --git a/target-mips/translate.c b/target-mips/translate.c
index 386e0e37d1..cefccb01a2 100644
--- a/target-mips/translate.c
+++ b/target-mips/translate.c
@@ -3186,7 +3186,7 @@ static void gen_mfc0 (CPUState *env, DisasContext *ctx, TCGv t0, int reg, int se
         }
         break;
     case 22:
-        /* ignored */
+        tcg_gen_movi_tl(t0, 0); /* unimplemented */
         rn = "'Diagnostic"; /* implementation dependent */
         break;
     case 23:
@@ -3266,12 +3266,13 @@ static void gen_mfc0 (CPUState *env, DisasContext *ctx, TCGv t0, int reg, int se
         }
         break;
     case 26:
-       rn = "ECC";
-       break;
+        tcg_gen_movi_tl(t0, 0); /* unimplemented */
+        rn = "ECC";
+        break;
     case 27:
         switch (sel) {
-        /* ignored */
         case 0 ... 3:
+            tcg_gen_movi_tl(t0, 0); /* unimplemented */
             rn = "CacheErr";
             break;
         default:
@@ -4372,7 +4373,7 @@ static void gen_dmfc0 (CPUState *env, DisasContext *ctx, TCGv t0, int reg, int s
         }
         break;
     case 22:
-        /* ignored */
+        tcg_gen_movi_tl(t0, 0); /* unimplemented */
         rn = "'Diagnostic"; /* implementation dependent */
         break;
     case 23:
@@ -4451,12 +4452,14 @@ static void gen_dmfc0 (CPUState *env, DisasContext *ctx, TCGv t0, int reg, int s
         }
         break;
     case 26:
-       rn = "ECC";
-       break;
+        tcg_gen_movi_tl(t0, 0); /* unimplemented */
+        rn = "ECC";
+        break;
     case 27:
         switch (sel) {
         /* ignored */
         case 0 ... 3:
+            tcg_gen_movi_tl(t0, 0); /* unimplemented */
             rn = "CacheErr";
             break;
         default:
@@ -8013,7 +8016,7 @@ static void decode_opc (CPUState *env, DisasContext *ctx)
                 case OPC_EMT:
                     check_insn(env, ctx, ASE_MT);
                     tcg_gen_helper_1_1(do_emt, t0, t0);
-                     break;
+                    break;
                 case OPC_DVPE:
                     check_insn(env, ctx, ASE_MT);
                     tcg_gen_helper_1_1(do_dvpe, t0, t0);