diff --git a/target-alpha/helper.h b/target-alpha/helper.h
index 9ffc372aff771ba1fcefb0e3679f73f441488f77..2dec57e44b25f31b329464e681ccc93fa8700f48 100644
--- a/target-alpha/helper.h
+++ b/target-alpha/helper.h
@@ -110,6 +110,9 @@ DEF_HELPER_2(stl_phys, void, i64, i64)
 DEF_HELPER_2(stq_phys, void, i64, i64)
 DEF_HELPER_2(stl_c_phys, i64, i64, i64)
 DEF_HELPER_2(stq_c_phys, i64, i64, i64)
+
+DEF_HELPER_FLAGS_0(tbia, TCG_CALL_CONST, void)
+DEF_HELPER_FLAGS_1(tbis, TCG_CALL_CONST, void, i64)
 #endif
 
 #include "def-helper.h"
diff --git a/target-alpha/op_helper.c b/target-alpha/op_helper.c
index 36b82899d0556348468ffe29d5cc47f5859e2d2a..d33271958fe2295ff38e4f20076eb1294cc756a1 100644
--- a/target-alpha/op_helper.c
+++ b/target-alpha/op_helper.c
@@ -1205,6 +1205,16 @@ void helper_hw_ret (uint64_t a)
         swap_shadow_regs(env);
     }
 }
+
+void helper_tbia(void)
+{
+    tlb_flush(env, 1);
+}
+
+void helper_tbis(uint64_t p)
+{
+    tlb_flush_page(env, p);
+}
 #endif
 
 /*****************************************************************************/
@@ -1335,5 +1345,4 @@ void tlb_fill (target_ulong addr, int is_write, int mmu_idx, void *retaddr)
     }
     env = saved_env;
 }
-
 #endif
diff --git a/target-alpha/translate.c b/target-alpha/translate.c
index e664d62aa3b447b7cccb3151b7cbdb87887d38b8..ad6c2ca448464fc9cfd77f692819a7e8de561f13 100644
--- a/target-alpha/translate.c
+++ b/target-alpha/translate.c
@@ -1621,7 +1621,6 @@ static void gen_mfpr(int ra, int regno)
 static void gen_mtpr(int rb, int regno)
 {
     TCGv tmp;
-    int data;
 
     if (rb == 31) {
         tmp = tcg_const_i64(0);
@@ -1629,16 +1628,27 @@ static void gen_mtpr(int rb, int regno)
         tmp = cpu_ir[rb];
     }
 
-    /* The basic registers are data only, and unknown registers
-       are read-zero, write-ignore.  */
-    data = cpu_pr_data(regno);
-    if (data != 0) {
-        if (data & PR_BYTE) {
-            tcg_gen_st8_i64(tmp, cpu_env, data & ~PR_BYTE);
-        } else if (data & PR_LONG) {
-            tcg_gen_st32_i64(tmp, cpu_env, data & ~PR_LONG);
-        } else {
-            tcg_gen_st_i64(tmp, cpu_env, data);
+    /* These two register numbers perform a TLB cache flush.  Thankfully we
+       can only do this inside PALmode, which means that the current basic
+       block cannot be affected by the change in mappings.  */
+    if (regno == 255) {
+        /* TBIA */
+        gen_helper_tbia();
+    } else if (regno == 254) {
+        /* TBIS */
+        gen_helper_tbis(tmp);
+    } else {
+        /* The basic registers are data only, and unknown registers
+           are read-zero, write-ignore.  */
+        int data = cpu_pr_data(regno);
+        if (data != 0) {
+            if (data & PR_BYTE) {
+                tcg_gen_st8_i64(tmp, cpu_env, data & ~PR_BYTE);
+            } else if (data & PR_LONG) {
+                tcg_gen_st32_i64(tmp, cpu_env, data & ~PR_LONG);
+            } else {
+                tcg_gen_st_i64(tmp, cpu_env, data);
+            }
         }
     }