diff --git a/include/mcl/fp.hpp b/include/mcl/fp.hpp
index 6703daf..48bd1b7 100644
--- a/include/mcl/fp.hpp
+++ b/include/mcl/fp.hpp
@@ -343,11 +343,16 @@ public:
 		set array x as little endian
 	*/
 	template<class S>
-	void setArray(bool *pb, const S *x, size_t n, mcl::fp::MaskMode mode = fp::NoMask)
+	void setArray_(bool *pb, const S *x, size_t n, mcl::fp::MaskMode mode = fp::NoMask)
 	{
 		*pb = fp::copyAndMask(v_, x, sizeof(S) * n, op_, mode);
 		toMont();
 	}
+	template<class S>
+	void setArray(bool *pb, const S *x, size_t n)
+	{
+		setArray_(pb, x, n, fp::NoMask);
+	}
 	/*
 		mask x with (1 << bitLen) and subtract p if x >= p
 	*/
@@ -364,7 +369,7 @@ public:
 	template<class S>
 	void setArrayMod(bool *pb, const S *x, size_t n)
 	{
-		setArray(pb, x, n, fp::Mod);
+		setArray_(pb, x, n, fp::Mod);
 	}
 
 	/*
@@ -415,7 +420,7 @@ public:
 	*/
 	void setLittleEndianMod(bool *pb, const void *buf, size_t bufSize)
 	{
-		setArray(pb, (const uint8_t *)buf, bufSize, mcl::fp::Mod);
+		setArrayMod(pb, (const uint8_t *)buf, bufSize);
 	}
 	/*
 		set (big endian % p)
@@ -432,7 +437,7 @@ public:
 		for (size_t i = 0; i < bufSize; i++) {
 			swapBuf[bufSize - 1 - i] = p[i];
 		}
-		setArray(pb, swapBuf, bufSize, mcl::fp::Mod);
+		setArray_(pb, swapBuf, bufSize, mcl::fp::Mod);
 	}
 	void setByCSPRNG(bool *pb, fp::RandGen rg = fp::RandGen())
 	{
diff --git a/include/mcl/impl/bn_c_impl.hpp b/include/mcl/impl/bn_c_impl.hpp
index fcaa151..b63c9b8 100644
--- a/include/mcl/impl/bn_c_impl.hpp
+++ b/include/mcl/impl/bn_c_impl.hpp
@@ -176,7 +176,7 @@ mclSize mclBnFr_getLittleEndian(void *buf, mclSize maxBufSize, const mclBnFr *x)
 int mclBnFr_setLittleEndianMod(mclBnFr *x, const void *buf, mclSize bufSize)
 {
 	bool b;
-	cast(x)->setArray(&b, (const char *)buf, bufSize, mcl::fp::Mod);
+	cast(x)->setArrayMod(&b, (const char *)buf, bufSize);
 	return b ? 0 : -1;
 }
 mclSize mclBnFr_deserialize(mclBnFr *x, const void *buf, mclSize bufSize)
diff --git a/src/fp.cpp b/src/fp.cpp
index 365da45..7f2cfef 100644
--- a/src/fp.cpp
+++ b/src/fp.cpp
@@ -676,25 +676,24 @@ bool copyAndMask(Unit *y, const void *x, size_t xByteSize, const Op& op, MaskMod
 #else
 		mx %= op.mp;
 #endif
-		const Unit *pmx = gmp::getUnit(mx);
-		size_t i = 0;
-		for (const size_t n = gmp::getUnitSize(mx); i < n; i++) {
-			y[i] = pmx[i];
-		}
-		for (; i < op.N; i++) {
-			y[i] = 0;
-		}
+		mcl::fp::convertArrayAsLE(y, op.N, gmp::getUnit(mx), gmp::getUnitSize(mx));
 		return true;
 	}
 	if (xByteSize > fpByteSize) {
 		if (maskMode == NoMask) return false;
 		xByteSize = fpByteSize;
 	}
+#if 0
+	if (!mcl::fp::convertArrayAsLE(y, op.N, x, xByteSize)) {
+		return false;
+	}
+#else
 	// QQQ : fixed later for big endian
 	copyByteToUnitAsLE(y, (const uint8_t*)x, xByteSize);
 	for (size_t i = (xByteSize + sizeof(Unit) - 1) / sizeof(Unit); i < op.N; i++) {
 		y[i] = 0;
 	}
+#endif
 	if (maskMode == mcl::fp::SmallMask || maskMode == mcl::fp::MaskAndMod) {
 		maskArray(y, op.N, op.bitSize);
 	}
diff --git a/test/fp_test.cpp b/test/fp_test.cpp
index 8883e69..9a8ee29 100644
--- a/test/fp_test.cpp
+++ b/test/fp_test.cpp
@@ -609,7 +609,7 @@ void setArrayModTest()
 		const size_t fpByteSize = unitByteSize * Fp::getOp().N;
 		Fp y;
 		bool b;
-		y.setArray(&b, px, xn, mcl::fp::Mod);
+		y.setArrayMod(&b, px, xn);
 		bool expected = xByteSize <= fpByteSize * 2;
 		CYBOZU_TEST_EQUAL(b, expected);
 		if (!b) continue;
@@ -1041,7 +1041,7 @@ CYBOZU_TEST_AUTO(main)
 #endif
 }
 
-CYBOZU_TEST_AUTO(copyByteToUnitAsLE)
+CYBOZU_TEST_AUTO(convertArrayAsLE)
 {
 	using namespace mcl::fp;
 #if MCL_SIZEOF_UNIT == 4
@@ -1050,18 +1050,19 @@ CYBOZU_TEST_AUTO(copyByteToUnitAsLE)
 	const Unit src[] = { uint64_t(0xaabbccdd12345678ull), uint64_t(0x87654321ffeeddcc) };
 #endif
 	const uint8_t ok[] = { 0x78, 0x56, 0x34, 0x12, 0xdd, 0xcc, 0xbb, 0xaa, 0xcc, 0xdd, 0xee, 0xff, 0x21, 0x43, 0x65, 0x87 };
-	mcl::fp::Unit dst[2];
+	const size_t dstN = 2;
+	mcl::fp::Unit dst[dstN];
 	for (size_t i = 1; i <= sizeof(dst); i++) {
 		memset(dst, 0xff, sizeof(dst));
-		mcl::fp::copyByteToUnitAsLE(dst, ok, i);
+		mcl::fp::convertArrayAsLE(dst, dstN, ok, i);
 		if (i < sizeof(Unit)) {
 			CYBOZU_TEST_EQUAL(src[0] & ((uint64_t(1) << (i * 8)) - 1), dst[0]);
-			CYBOZU_TEST_EQUAL(dst[1], Unit(-1));
+			CYBOZU_TEST_EQUAL(dst[1], 0);
 			continue;
 		}
 		CYBOZU_TEST_EQUAL(dst[0], src[0]);
 		if (i == sizeof(Unit)) {
-			CYBOZU_TEST_EQUAL(dst[1], Unit(-1));
+			CYBOZU_TEST_EQUAL(dst[1], 0);
 			continue;
 		}
 		if (i < sizeof(dst)) {
@@ -1071,7 +1072,7 @@ CYBOZU_TEST_AUTO(copyByteToUnitAsLE)
 		CYBOZU_TEST_EQUAL(src[1], dst[1]);
 	}
 	dst[0] = 1;
-	copyByteToUnitAsLE(dst, ok, 0);
+	mcl::fp::convertArrayAsLE(dst, 0, ok, 1);
 	CYBOZU_TEST_EQUAL(dst[0], 1u);
 }