diff --git a/libff/algebra/fields/fp.tcc b/libff/algebra/fields/fp.tcc
index 2d919faa..db6cfc08 100755
--- a/libff/algebra/fields/fp.tcc
+++ b/libff/algebra/fields/fp.tcc
@@ -733,7 +733,8 @@ Fp_model<n, modulus> Fp_model<n,modulus>::random_element() /// returns random el
             const std::size_t part = bitno/GMP_NUMB_BITS;
             const std::size_t bit = bitno - (GMP_NUMB_BITS*part);
 
-            r.mont_repr.data[part] &= ~(1ul<<bit);
+            static const mp_limb_t one = 1;
+            r.mont_repr.data[part] &= ~(one<<bit);
 
             bitno--;
         }
diff --git a/libff/algebra/fields/fp12_2over3over2.tcc b/libff/algebra/fields/fp12_2over3over2.tcc
index 6220c4f5..b2523161 100755
--- a/libff/algebra/fields/fp12_2over3over2.tcc
+++ b/libff/algebra/fields/fp12_2over3over2.tcc
@@ -348,7 +348,8 @@ Fp12_2over3over2_model<n, modulus> Fp12_2over3over2_model<n,modulus>::cyclotomic
                 res = res.cyclotomic_squared();
             }
 
-            if (exponent.data[i] & (1ul<<j))
+            static const mp_limb_t one = 1;
+            if (exponent.data[i] & (one<<j))
             {
                 found_one = true;
                 res = res * (*this);
diff --git a/libff/common/rng.tcc b/libff/common/rng.tcc
index 92eecea1..314bb184 100755
--- a/libff/common/rng.tcc
+++ b/libff/common/rng.tcc
@@ -57,7 +57,8 @@ FieldT SHA512_rng(const uint64_t idx)
             const std::size_t part = bitno/GMP_NUMB_BITS;
             const std::size_t bit = bitno - (GMP_NUMB_BITS*part);
 
-            rval.data[part] &= ~(1ul<<bit);
+            static const mp_limb_t one = 1;
+            rval.data[part] &= ~(one<<bit);
 
             bitno--;
         }