diff --git a/src/hotspot/cpu/s390/interp_masm_s390.cpp b/src/hotspot/cpu/s390/interp_masm_s390.cpp
index 5e80817aaba..c8d08c92dde 100644
--- a/src/hotspot/cpu/s390/interp_masm_s390.cpp
+++ b/src/hotspot/cpu/s390/interp_masm_s390.cpp
@@ -780,7 +780,7 @@ void InterpreterMacroAssembler::unlock_if_synchronized_method(TosState state,
     get_method(R_method);
     verify_oop(Z_tos, state);
     push(state); // Save tos/result.
-    testbit(method2_(R_method, access_flags), JVM_ACC_SYNCHRONIZED_BIT);
+    testbit_ushort(method2_(R_method, access_flags), JVM_ACC_SYNCHRONIZED_BIT);
     z_bfalse(unlocked);
 
     // Don't unlock anything if the _do_not_unlock_if_synchronized flag
diff --git a/src/hotspot/cpu/s390/macroAssembler_s390.cpp b/src/hotspot/cpu/s390/macroAssembler_s390.cpp
index a069d6ceafb..83783daf55e 100644
--- a/src/hotspot/cpu/s390/macroAssembler_s390.cpp
+++ b/src/hotspot/cpu/s390/macroAssembler_s390.cpp
@@ -1015,6 +1015,18 @@ void MacroAssembler::load_and_test_long(Register dst, const Address &a) {
   z_ltg(dst, a);
 }
 
+// Test a bit in memory for 2 byte datatype.
+void MacroAssembler::testbit_ushort(const Address &a, unsigned int bit) {
+  assert(a.index() == noreg, "no index reg allowed in testbit");
+  if (bit <= 7) {
+    z_tm(a.disp() + 1, a.base(), 1 << bit);
+  } else if (bit <= 15) {
+    z_tm(a.disp() + 0, a.base(), 1 << (bit - 8));
+  } else {
+    ShouldNotReachHere();
+  }
+}
+
 // Test a bit in memory.
 void MacroAssembler::testbit(const Address &a, unsigned int bit) {
   assert(a.index() == noreg, "no index reg allowed in testbit");
diff --git a/src/hotspot/cpu/s390/macroAssembler_s390.hpp b/src/hotspot/cpu/s390/macroAssembler_s390.hpp
index 15968812818..46821d19d4e 100644
--- a/src/hotspot/cpu/s390/macroAssembler_s390.hpp
+++ b/src/hotspot/cpu/s390/macroAssembler_s390.hpp
@@ -199,6 +199,7 @@ class MacroAssembler: public Assembler {
 
   // Test a bit in memory. Result is reflected in CC.
   void testbit(const Address &a, unsigned int bit);
+  void testbit_ushort(const Address &a, unsigned int bit);
   // Test a bit in a register. Result is reflected in CC.
   void testbit(Register r, unsigned int bitPos);
 
diff --git a/src/hotspot/cpu/s390/sharedRuntime_s390.cpp b/src/hotspot/cpu/s390/sharedRuntime_s390.cpp
index 2396a2a7105..ebc6baec673 100644
--- a/src/hotspot/cpu/s390/sharedRuntime_s390.cpp
+++ b/src/hotspot/cpu/s390/sharedRuntime_s390.cpp
@@ -2395,7 +2395,7 @@ AdapterHandlerEntry* SharedRuntime::generate_i2c2i_adapters(MacroAssembler *masm
     Label L_skip_barrier;
 
     { // Bypass the barrier for non-static methods
-      __ testbit(Address(Z_method, Method::access_flags_offset()), JVM_ACC_STATIC_BIT);
+      __ testbit_ushort(Address(Z_method, Method::access_flags_offset()), JVM_ACC_STATIC_BIT);
       __ z_bfalse(L_skip_barrier); // non-static
     }
 
diff --git a/src/hotspot/cpu/s390/templateInterpreterGenerator_s390.cpp b/src/hotspot/cpu/s390/templateInterpreterGenerator_s390.cpp
index 1c4089d5beb..e1a4a9b2c4b 100644
--- a/src/hotspot/cpu/s390/templateInterpreterGenerator_s390.cpp
+++ b/src/hotspot/cpu/s390/templateInterpreterGenerator_s390.cpp
@@ -164,7 +164,7 @@ address TemplateInterpreterGenerator::generate_slow_signature_handler() {
     // Therefore add 3 to address that byte within "_flags".
     // Reload method. VM call above may have destroyed register contents
     __ get_method(method);
-    __ testbit(method2_(method, access_flags), JVM_ACC_STATIC_BIT);
+    __ testbit_ushort(method2_(method, access_flags), JVM_ACC_STATIC_BIT);
     method = noreg;  // end of life
     __ z_btrue(isStatic);
 
@@ -883,7 +883,7 @@ void TemplateInterpreterGenerator::lock_method(void) {
   address reentry = nullptr;
   {
     Label L;
-    __ testbit(method2_(method, access_flags), JVM_ACC_SYNCHRONIZED_BIT);
+    __ testbit_ushort(method2_(method, access_flags), JVM_ACC_SYNCHRONIZED_BIT);
     __ z_btrue(L);
     reentry = __ stop_chain_static(reentry, "method doesn't need synchronization");
     __ bind(L);
@@ -897,7 +897,7 @@ void TemplateInterpreterGenerator::lock_method(void) {
     Label     done;
     Label     static_method;
 
-    __ testbit(method2_(method, access_flags), JVM_ACC_STATIC_BIT);
+    __ testbit_ushort(method2_(method, access_flags), JVM_ACC_STATIC_BIT);
     __ z_btrue(static_method);
 
     // non-static method: Load receiver obj from stack.
@@ -1349,15 +1349,17 @@ address TemplateInterpreterGenerator::generate_native_entry(bool synchronized) {
 
   // Make sure method is native and not abstract.
 #ifdef ASSERT
+  // _access_flags must be a 16 bit value.
+  assert(sizeof(AccessFlags) == 2, "testbit_ushort will fail");
   address reentry = nullptr;
   { Label L;
-    __ testbit(method_(access_flags), JVM_ACC_NATIVE_BIT);
+    __ testbit_ushort(method_(access_flags), JVM_ACC_NATIVE_BIT);
     __ z_btrue(L);
     reentry = __ stop_chain_static(reentry, "tried to execute non-native method as native");
     __ bind(L);
   }
   { Label L;
-    __ testbit(method_(access_flags), JVM_ACC_ABSTRACT_BIT);
+    __ testbit_ushort(method_(access_flags), JVM_ACC_ABSTRACT_BIT);
     __ z_bfalse(L);
     reentry = __ stop_chain_static(reentry, "tried to execute abstract method as non-abstract");
     __ bind(L);
@@ -1403,7 +1405,7 @@ address TemplateInterpreterGenerator::generate_native_entry(bool synchronized) {
 #ifdef ASSERT
     { Label L;
       __ get_method(Z_R1_scratch);
-      __ testbit(method2_(Z_R1_scratch, access_flags), JVM_ACC_SYNCHRONIZED_BIT);
+      __ testbit_ushort(method2_(Z_R1_scratch, access_flags), JVM_ACC_SYNCHRONIZED_BIT);
       __ z_bfalse(L);
       reentry = __ stop_chain_static(reentry, "method needs synchronization");
       __ bind(L);
@@ -1461,7 +1463,7 @@ address TemplateInterpreterGenerator::generate_native_entry(bool synchronized) {
   // Pass mirror handle if static call.
   {
     Label method_is_not_static;
-    __ testbit(method2_(Rmethod, access_flags), JVM_ACC_STATIC_BIT);
+    __ testbit_ushort(method2_(Rmethod, access_flags), JVM_ACC_STATIC_BIT);
     __ z_bfalse(method_is_not_static);
     // Load mirror from interpreter frame.
     __ z_lg(Z_R1, _z_ijava_state_neg(mirror), Z_fp);
@@ -1719,13 +1721,13 @@ address TemplateInterpreterGenerator::generate_normal_entry(bool synchronized) {
 #ifdef ASSERT
   address reentry = nullptr;
   { Label L;
-    __ testbit(method_(access_flags), JVM_ACC_NATIVE_BIT);
+    __ testbit_ushort(method_(access_flags), JVM_ACC_NATIVE_BIT);
     __ z_bfalse(L);
     reentry = __ stop_chain_static(reentry, "tried to execute native method as non-native");
     __ bind(L);
   }
   { Label L;
-    __ testbit(method_(access_flags), JVM_ACC_ABSTRACT_BIT);
+    __ testbit_ushort(method_(access_flags), JVM_ACC_ABSTRACT_BIT);
     __ z_bfalse(L);
     reentry = __ stop_chain_static(reentry, "tried to execute abstract method as non-abstract");
     __ bind(L);
@@ -1775,7 +1777,7 @@ address TemplateInterpreterGenerator::generate_normal_entry(bool synchronized) {
 #ifdef ASSERT
     { Label L;
       __ get_method(Z_R1_scratch);
-      __ testbit(method2_(Z_R1_scratch, access_flags), JVM_ACC_SYNCHRONIZED_BIT);
+      __ testbit_ushort(method2_(Z_R1_scratch, access_flags), JVM_ACC_SYNCHRONIZED_BIT);
       __ z_bfalse(L);
       reentry = __ stop_chain_static(reentry, "method needs synchronization");
       __ bind(L);