diff --git a/include/mcl/vint.hpp b/include/mcl/vint.hpp
index 45d8454..aa810ab 100644
--- a/include/mcl/vint.hpp
+++ b/include/mcl/vint.hpp
@@ -1491,9 +1491,10 @@ public:
 	*/
 	static void divMod(VintT *q, VintT& r, const VintT& x, const VintT& y)
 	{
-		bool qsign = x.isNeg_ ^ y.isNeg_;
+		bool xNeg = x.isNeg_;
+		bool qsign = xNeg ^ y.isNeg_;
 		udiv(q, r, x.buf_, x.size(), y.buf_, y.size());
-		r.isNeg_ = x.isNeg_;
+		r.isNeg_ = xNeg;
 		if (q) q->isNeg_ = qsign;
 	}
 	static void div(VintT& q, const VintT& x, const VintT& y)
diff --git a/test/vint_test.cpp b/test/vint_test.cpp
index d96c1c7..bc60850 100644
--- a/test/vint_test.cpp
+++ b/test/vint_test.cpp
@@ -973,6 +973,8 @@ CYBOZU_TEST_AUTO(Vint)
 		CYBOZU_TEST_EQUAL(q2, tbl[i].q2);
 		CYBOZU_TEST_EQUAL(r2, tbl[i].r2);
 		CYBOZU_TEST_EQUAL(q2 * b + r2, a);
+		// alias pattern
+		// quotRem
 		r2 = 0;
 		Vint::quotRem(&b, r2, a, b);
 		CYBOZU_TEST_EQUAL(b, tbl[i].q2);
@@ -1000,6 +1002,36 @@ CYBOZU_TEST_AUTO(Vint)
 		Vint::quotRem(&q, a, a, a);
 		CYBOZU_TEST_EQUAL(q, 1);
 		CYBOZU_TEST_EQUAL(a, 0);
+		// divMod
+		a = tbl[i].a;
+		b = tbl[i].b;
+		r = 0;
+		Vint::divMod(&b, r, a, b);
+		CYBOZU_TEST_EQUAL(b, tbl[i].q);
+		CYBOZU_TEST_EQUAL(r, tbl[i].r);
+		b = tbl[i].b;
+		r = 0;
+		Vint::divMod(&a, r, a, b);
+		CYBOZU_TEST_EQUAL(a, tbl[i].q);
+		CYBOZU_TEST_EQUAL(r, tbl[i].r);
+		a = tbl[i].a;
+		q = 0;
+		Vint::divMod(&q, a, a, b);
+		CYBOZU_TEST_EQUAL(q, tbl[i].q);
+		CYBOZU_TEST_EQUAL(a, tbl[i].r);
+		a = tbl[i].a;
+		q = 0;
+		Vint::divMod(&q, a, a, b);
+		CYBOZU_TEST_EQUAL(q, tbl[i].q);
+		CYBOZU_TEST_EQUAL(a, tbl[i].r);
+		a = tbl[i].a;
+		q = 0;
+		Vint::divMod(&q, b, a, b);
+		CYBOZU_TEST_EQUAL(q, tbl[i].q);
+		CYBOZU_TEST_EQUAL(b, tbl[i].r);
+		Vint::divMod(&q, a, a, a);
+		CYBOZU_TEST_EQUAL(q, 1);
+		CYBOZU_TEST_EQUAL(a, 0);
 	}
 	CYBOZU_TEST_EQUAL(Vint("15") / Vint("3"), Vint("5"));
 	CYBOZU_TEST_EQUAL(Vint("15") / Vint("-3"), Vint("-5"));