diff --git a/src/rng.c b/src/rng.c
index 3020680..64dac45 100644
--- a/src/rng.c
+++ b/src/rng.c
@@ -107,7 +107,7 @@ static void mt_genArray(void) {
     mt_y = (MT[i] & 0x80000000) + ((MT[i] % 624) & 0x7FFFFFFF);
     if(mt_y % 2)
       /* Odd. */
-      MT[i] = (MT[(i+397) % 624] ^ (mt_y >> 1)) ^ 2567483615;
+      MT[i] = (MT[(i+397) % 624] ^ (mt_y >> 1)) ^ 2567483615U;
     else
       /* Even. */
       MT[i] = MT[(i+397) % 624] ^ (mt_y >> 1);
@@ -124,8 +124,8 @@ static uint32_t mt_getInt(void) {
 
   mt_y = MT[mt_pos++];
   mt_y ^= mt_y >> 11;
-  mt_y ^= (mt_y << 7)   & 2636928640;
-  mt_y ^= (mt_y << 15)  & 4022730752;
+  mt_y ^= (mt_y << 7)   & 2636928640U;
+  mt_y ^= (mt_y << 15)  & 4022730752U;
   mt_y ^= (mt_y >> 18);
 
   return mt_y;