diff --git a/addrfilt.c b/addrfilt.c
index c998b0c..8ed1574 100644
--- a/addrfilt.c
+++ b/addrfilt.c
@@ -62,7 +62,7 @@ split_ip6(IPAddr *ip, uint32_t *dst)
   int i;
 
   for (i = 0; i < 4; i++)
-    dst[i] = ip->addr.in6[i * 4 + 0] << 24 |
+    dst[i] = (uint32_t)ip->addr.in6[i * 4 + 0] << 24 |
              ip->addr.in6[i * 4 + 1] << 16 |
              ip->addr.in6[i * 4 + 2] << 8 |
              ip->addr.in6[i * 4 + 3];
diff --git a/conf.c b/conf.c
index 2301993..2a92273 100644
--- a/conf.c
+++ b/conf.c
@@ -700,11 +700,11 @@ parse_refclock(char *line)
     if (!strcasecmp(cmd, "refid")) {
       if (sscanf(line, "%4s%n", (char *)ref, &n) != 1)
         break;
-      ref_id = ref[0] << 24 | ref[1] << 16 | ref[2] << 8 | ref[3];
+      ref_id = (uint32_t)ref[0] << 24 | ref[1] << 16 | ref[2] << 8 | ref[3];
     } else if (!strcasecmp(cmd, "lock")) {
       if (sscanf(line, "%4s%n", (char *)ref, &n) != 1)
         break;
-      lock_ref_id = ref[0] << 24 | ref[1] << 16 | ref[2] << 8 | ref[3];
+      lock_ref_id = (uint32_t)ref[0] << 24 | ref[1] << 16 | ref[2] << 8 | ref[3];
     } else if (!strcasecmp(cmd, "poll")) {
       if (sscanf(line, "%d%n", &poll, &n) != 1) {
         break;
diff --git a/refclock.c b/refclock.c
index 26193f6..8791d43 100644
--- a/refclock.c
+++ b/refclock.c
@@ -233,7 +233,7 @@ RCL_AddRefclock(RefclockParameters *params)
     if (index >= 10)
       ref[2] = (index / 10) % 10 + '0';
 
-    inst->ref_id = ref[0] << 24 | ref[1] << 16 | ref[2] << 8 | ref[3];
+    inst->ref_id = (uint32_t)ref[0] << 24 | ref[1] << 16 | ref[2] << 8 | ref[3];
   }
 
   if (inst->driver->poll) {