diff --git a/target-mips/cpu.h b/target-mips/cpu.h
index fe1c4b8..6325e15 100644
--- a/target-mips/cpu.h
+++ b/target-mips/cpu.h
@@ -343,6 +343,7 @@ struct CPUMIPSState {
     int32_t CP0_Count;
     target_ulong CP0_EntryHi;
 #define CP0EnHi_EHINV 10
+    target_ulong CP0_EntryHi_ASID_mask;
     int32_t CP0_Compare;
     int32_t CP0_Status;
 #define CP0St_CU3   31
@@ -503,6 +504,7 @@ struct CPUMIPSState {
     int CP0_LLAddr_shift;
     target_ulong CP0_WatchLo[8];
     int32_t CP0_WatchHi[8];
+#define CP0WH_ASID 16
     target_ulong CP0_XContext;
     int32_t CP0_Framemask;
     int32_t CP0_Debug;
diff --git a/target-mips/helper.c b/target-mips/helper.c
index 1402ff0..1e194e9 100644
--- a/target-mips/helper.c
+++ b/target-mips/helper.c
@@ -67,7 +67,7 @@ int fixed_mmu_map_address (CPUMIPSState *env, hwaddr *physical, int *prot,
 int r4k_map_address (CPUMIPSState *env, hwaddr *physical, int *prot,
                      target_ulong address, int rw, int access_type)
 {
-    uint8_t ASID = env->CP0_EntryHi & 0xFF;
+    uint8_t ASID = env->CP0_EntryHi & env->CP0_EntryHi_ASID_mask;
     int i;
 
     for (i = 0; i < env->tlb->tlb_in_use; i++) {
@@ -249,7 +249,7 @@ void sync_c0_status(CPUMIPSState *env, CPUMIPSState *cpu, int tc)
     cu = (v >> CP0St_CU0) & 0xf;
     mx = (v >> CP0St_MX) & 0x1;
     ksu = (v >> CP0St_KSU) & 0x3;
-    asid = env->CP0_EntryHi & 0xff;
+    asid = env->CP0_EntryHi & env->CP0_EntryHi_ASID_mask;
 
     tcstatus = cu << CP0TCSt_TCU0;
     tcstatus |= mx << CP0TCSt_TMX;
@@ -395,8 +395,8 @@ static void raise_mmu_exception(CPUMIPSState *env, target_ulong address,
     env->CP0_BadVAddr = address;
     env->CP0_Context = (env->CP0_Context & ~0x007fffff) |
                        ((address >> 9) & 0x007ffff0);
-    env->CP0_EntryHi =
-        (env->CP0_EntryHi & 0xFF) | (address & (TARGET_PAGE_MASK << 1));
+    env->CP0_EntryHi = (env->CP0_EntryHi & env->CP0_EntryHi_ASID_mask) |
+                       (address & (TARGET_PAGE_MASK << 1));
 #if defined(TARGET_MIPS64)
     env->CP0_EntryHi &= env->SEGMask;
     env->CP0_XContext =
@@ -898,7 +898,7 @@ void r4k_invalidate_tlb (CPUMIPSState *env, int idx, int use_extra)
     r4k_tlb_t *tlb;
     target_ulong addr;
     target_ulong end;
-    uint8_t ASID = env->CP0_EntryHi & 0xFF;
+    uint8_t ASID = env->CP0_EntryHi & env->CP0_EntryHi_ASID_mask;
     target_ulong mask;
 
     tlb = &env->tlb->mmu.r4k.tlb[idx];
diff --git a/target-mips/op_helper.c b/target-mips/op_helper.c
index 69daade..1562f22 100644
--- a/target-mips/op_helper.c
+++ b/target-mips/op_helper.c
@@ -679,7 +679,7 @@ static void sync_c0_tcstatus(CPUMIPSState *cpu, int tc,
 
     tcu = (v >> CP0TCSt_TCU0) & 0xf;
     tmx = (v >> CP0TCSt_TMX) & 0x1;
-    tasid = v & 0xff;
+    tasid = v & cpu->CP0_EntryHi_ASID_mask;
     tksu = (v >> CP0TCSt_TKSU) & 0x3;
 
     status = tcu << CP0St_CU0;
@@ -690,7 +690,7 @@ static void sync_c0_tcstatus(CPUMIPSState *cpu, int tc,
     cpu->CP0_Status |= status;
 
     /* Sync the TASID with EntryHi.  */
-    cpu->CP0_EntryHi &= ~0xff;
+    cpu->CP0_EntryHi &= ~cpu->CP0_EntryHi_ASID_mask;
     cpu->CP0_EntryHi |= tasid;
 
     compute_hflags(cpu);
@@ -702,7 +702,7 @@ static void sync_c0_entryhi(CPUMIPSState *cpu, int tc)
     int32_t *tcst;
     uint32_t asid, v = cpu->CP0_EntryHi;
 
-    asid = v & 0xff;
+    asid = v & cpu->CP0_EntryHi_ASID_mask;
 
     if (tc == cpu->current_tc) {
         tcst = &cpu->active_tc.CP0_TCStatus;
@@ -710,7 +710,7 @@ static void sync_c0_entryhi(CPUMIPSState *cpu, int tc)
         tcst = &cpu->tcs[tc].CP0_TCStatus;
     }
 
-    *tcst &= ~0xff;
+    *tcst &= ~cpu->CP0_EntryHi_ASID_mask;
     *tcst |= asid;
 }
 
@@ -1403,7 +1403,7 @@ void helper_mtc0_count(CPUMIPSState *env, target_ulong arg1)
 void helper_mtc0_entryhi(CPUMIPSState *env, target_ulong arg1)
 {
     target_ulong old, val, mask;
-    mask = (TARGET_PAGE_MASK << 1) | 0xFF;
+    mask = (TARGET_PAGE_MASK << 1) | env->CP0_EntryHi_ASID_mask;
     if (((env->CP0_Config4 >> CP0C4_IE) & 0x3) >= 2) {
         mask |= 1 << CP0EnHi_EHINV;
     }
@@ -1429,8 +1429,10 @@ void helper_mtc0_entryhi(CPUMIPSState *env, target_ulong arg1)
         sync_c0_entryhi(env, env->current_tc);
     }
     /* If the ASID changes, flush qemu's TLB.  */
-    if ((old & 0xFF) != (val & 0xFF))
+    if ((old & env->CP0_EntryHi_ASID_mask) !=
+        (val & env->CP0_EntryHi_ASID_mask)) {
         cpu_mips_tlb_flush(env, 1);
+    }
 }
 
 void helper_mttc0_entryhi(CPUMIPSState *env, target_ulong arg1)
@@ -1631,7 +1633,8 @@ void helper_mtc0_watchlo(CPUMIPSState *env, target_ulong arg1, uint32_t sel)
 
 void helper_mtc0_watchhi(CPUMIPSState *env, target_ulong arg1, uint32_t sel)
 {
-    env->CP0_WatchHi[sel] = (arg1 & 0x40FF0FF8);
+    int mask = 0x40000FF8 | (env->CP0_EntryHi_ASID_mask << CP0WH_ASID);
+    env->CP0_WatchHi[sel] = arg1 & mask;
     env->CP0_WatchHi[sel] &= ~(env->CP0_WatchHi[sel] & arg1 & 0x7);
 }
 
@@ -1989,7 +1992,7 @@ static void r4k_fill_tlb(CPUMIPSState *env, int idx)
 #if defined(TARGET_MIPS64)
     tlb->VPN &= env->SEGMask;
 #endif
-    tlb->ASID = env->CP0_EntryHi & 0xFF;
+    tlb->ASID = env->CP0_EntryHi & env->CP0_EntryHi_ASID_mask;
     tlb->PageMask = env->CP0_PageMask;
     tlb->G = env->CP0_EntryLo0 & env->CP0_EntryLo1 & 1;
     tlb->V0 = (env->CP0_EntryLo0 & 2) != 0;
@@ -2010,7 +2013,7 @@ void r4k_helper_tlbinv(CPUMIPSState *env)
 {
     int idx;
     r4k_tlb_t *tlb;
-    uint8_t ASID = env->CP0_EntryHi & 0xFF;
+    uint8_t ASID = env->CP0_EntryHi & env->CP0_EntryHi_ASID_mask;
 
     for (idx = 0; idx < env->tlb->nb_tlb; idx++) {
         tlb = &env->tlb->mmu.r4k.tlb[idx];
@@ -2045,7 +2048,7 @@ void r4k_helper_tlbwi(CPUMIPSState *env)
 #if defined(TARGET_MIPS64)
     VPN &= env->SEGMask;
 #endif
-    ASID = env->CP0_EntryHi & 0xff;
+    ASID = env->CP0_EntryHi & env->CP0_EntryHi_ASID_mask;
     G = env->CP0_EntryLo0 & env->CP0_EntryLo1 & 1;
     V0 = (env->CP0_EntryLo0 & 2) != 0;
     D0 = (env->CP0_EntryLo0 & 4) != 0;
@@ -2081,7 +2084,7 @@ void r4k_helper_tlbp(CPUMIPSState *env)
     uint8_t ASID;
     int i;
 
-    ASID = env->CP0_EntryHi & 0xFF;
+    ASID = env->CP0_EntryHi & env->CP0_EntryHi_ASID_mask;
     for (i = 0; i < env->tlb->nb_tlb; i++) {
         tlb = &env->tlb->mmu.r4k.tlb[i];
         /* 1k pages are not supported. */
@@ -2136,7 +2139,7 @@ void r4k_helper_tlbr(CPUMIPSState *env)
     uint8_t ASID;
     int idx;
 
-    ASID = env->CP0_EntryHi & 0xFF;
+    ASID = env->CP0_EntryHi & env->CP0_EntryHi_ASID_mask;
     idx = (env->CP0_Index & ~0x80000000) % env->tlb->nb_tlb;
     tlb = &env->tlb->mmu.r4k.tlb[idx];
 
diff --git a/target-mips/translate.c b/target-mips/translate.c
index c302fa3..01510b3 100644
--- a/target-mips/translate.c
+++ b/target-mips/translate.c
@@ -20302,6 +20302,7 @@ void cpu_state_reset(CPUMIPSState *env)
     if (env->CP0_Config3 & (1 << CP0C3_CMGCR)) {
         env->CP0_CMGCRBase = 0x1fbf8000 >> 4;
     }
+    env->CP0_EntryHi_ASID_mask = 0xff;
     env->CP0_Status = (1 << CP0St_BEV) | (1 << CP0St_ERL);
     /* vectored interrupts not implemented, timer on int 7,
        no performance counters. */
