diff --git a/include/mcl/fp.hpp b/include/mcl/fp.hpp
index 4e45814..406b8b7 100644
--- a/include/mcl/fp.hpp
+++ b/include/mcl/fp.hpp
@@ -38,11 +38,6 @@ struct ZnTag;
 
 namespace fp {
 
-// copy src to dst as little endian
-void copyByteToUnitAsLE(Unit *dst, const uint8_t *src, size_t byteSize);
-
-bool copyAndMask(Unit *y, const void *x, size_t xByteSize, const Op& op, MaskMode maskMode);
-
 uint64_t getUint64(bool *pb, const fp::Block& b);
 int64_t getInt64(bool *pb, fp::Block& b, const fp::Op& op);
 
diff --git a/src/fp.cpp b/src/fp.cpp
index caad342..e4e5396 100644
--- a/src/fp.cpp
+++ b/src/fp.cpp
@@ -632,21 +632,6 @@ bool Op::init(const mpz_class& _p, size_t maxBitSize, int _xi_a, Mode mode, size
 	return fp::initForMont(*this, p, mode);
 }
 
-void copyByteToUnitAsLE(Unit *dst, const uint8_t *src, size_t byteSize)
-{
-	while (byteSize >= sizeof(Unit)) {
-		*dst++ = getUnitAsLE(src);
-		src += sizeof(Unit);
-		byteSize -= sizeof(Unit);
-	}
-	if (byteSize == 0) return;
-	Unit x = 0;
-	for (size_t i = 0; i < byteSize; i++) {
-		x |= Unit(src[i]) << (i * 8);
-	}
-	*dst = x;
-}
-
 #ifndef CYBOZU_DONT_USE_STRING
 int detectIoMode(int ioMode, const std::ios_base& ios)
 {
@@ -662,43 +647,6 @@ int detectIoMode(int ioMode, const std::ios_base& ios)
 }
 #endif
 
-bool copyAndMask(Unit *y, const void *x, size_t xByteSize, const Op& op, MaskMode maskMode)
-{
-	const size_t fpByteSize = sizeof(Unit) * op.N;
-	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);
-	}
-	if (isGreaterOrEqualArray(y, op.p, op.N)) {
-		switch (maskMode) {
-		case mcl::fp::NoMask: return false;
-		case mcl::fp::SmallMask:
-			maskArray(y, op.N, op.bitSize - 1);
-			break;
-		case mcl::fp::MaskAndMod:
-		default:
-			op.fp_subPre(y, y, op.p);
-			break;
-		}
-	}
-	assert(isLessArray(y, op.p, op.N));
-	return true;
-}
-
 static bool isInUint64(uint64_t *pv, const fp::Block& b)
 {
 	assert(fp::UnitBitSize == 32 || fp::UnitBitSize == 64);