diff --git a/sample/Makefile b/sample/Makefile
index 62c7dcf..5a84bcd 100644
--- a/sample/Makefile
+++ b/sample/Makefile
@@ -30,7 +30,7 @@ else
 endif
 
 ifeq ($(BIT),64)
-TARGET += test64 bf64 memfunc64 test_util64 jmp_table64
+TARGET += test64 bf64 memfunc64 test_util64 jmp_table64 zero_upper
 ifeq ($(BOOST_EXIST),1)
 TARGET += calc64 #calc2_64
 endif
@@ -103,6 +103,10 @@ profiler: profiler.cpp ../xbyak/xbyak_util.h
 	$(CXX) $(CFLAGS) profiler.cpp -o $@
 profiler-vtune: profiler.cpp ../xbyak/xbyak_util.h
 	$(CXX) $(CFLAGS) profiler.cpp -o $@ -DXBYAK_USE_VTUNE -I /opt/intel/vtune_amplifier/include/ -L /opt/intel/vtune_amplifier/lib64 -ljitprofiling -ldl
+zero_upper: zero_upper.cpp $(XBYAK_INC)
+	$(CXX) $(CFLAGS) zero_upper.cpp -o $@
+test_zero_upper: zero_upper
+	sde -future -- ./zero_upper
 
 clean:
 	rm -rf $(TARGET) profiler profiler-vtune
diff --git a/sample/zero_upper.cpp b/sample/zero_upper.cpp
new file mode 100644
index 0000000..46dcca9
--- /dev/null
+++ b/sample/zero_upper.cpp
@@ -0,0 +1,48 @@
+/*
+	An example of T_zu (zero upper) flag
+	> g++ zero_upper.cpp -I ../xbyak
+	> sde -future -- ./a.out
+*/
+#include <stdio.h>
+#include <xbyak/xbyak.h>
+
+using namespace Xbyak;
+
+struct Code : Xbyak::CodeGenerator {
+	Code(int mode)
+	{
+		mov(eax, 0x12345678);
+		cmp(eax, eax); // ZF=1
+		switch (mode) {
+		case 0: // imul
+			puts("imul");
+			imul(ax,ax, 0x1234);
+			break;
+		case 1: // imul+zu
+			puts("imul+zu");
+			imul(ax|T_zu, ax, 0x1234);
+			break;
+		case 2: // setz
+			puts("setz");
+			setz(al);
+			break;
+		case 3: // setz+zu
+			puts("setz+zu");
+			setz(al|T_zu);
+			break;
+		}
+		ret();
+	}
+};
+
+int main()
+	try
+{
+	for (int mode = 0; mode < 4; mode++) {
+		Code c(mode);
+		auto f = c.getCode<int (*)()>();
+		printf("ret=%08x\n", f());
+	}
+} catch (std::exception& e) {
+	printf("ERR %s\n", e.what());
+}