diff --git a/crypto_kem/mceliece348864f/vec/pk_gen.c b/crypto_kem/mceliece348864f/vec/pk_gen.c
index b47c27a5..314a809c 100644
--- a/crypto_kem/mceliece348864f/vec/pk_gen.c
+++ b/crypto_kem/mceliece348864f/vec/pk_gen.c
@@ -57,7 +57,7 @@ static inline int ctz(uint64_t in) {
     int i, b, m = 0, r = 0;
 
     for (i = 0; i < 64; i++) {
-        b = ((int)in >> i) & 1;
+        b = ((int)(in >> i)) & 1;
         m |= b;
         r += (m ^ 1) & (b ^ 1);
     }
diff --git a/crypto_kem/mceliece460896f/vec/pk_gen.c b/crypto_kem/mceliece460896f/vec/pk_gen.c
index 7aa02221..5b1bb6cb 100644
--- a/crypto_kem/mceliece460896f/vec/pk_gen.c
+++ b/crypto_kem/mceliece460896f/vec/pk_gen.c
@@ -57,7 +57,7 @@ static inline int ctz(uint64_t in) {
     int i, b, m = 0, r = 0;
 
     for (i = 0; i < 64; i++) {
-        b = ((int)in >> i) & 1;
+        b = ((int)(in >> i)) & 1;
         m |= b;
         r += (m ^ 1) & (b ^ 1);
     }