diff --git a/src/misc/bitSet.cpp b/src/misc/bitSet.cpp
index a2110f9..de19ea9 100644
--- a/src/misc/bitSet.cpp
+++ b/src/misc/bitSet.cpp
@@ -359,7 +359,7 @@ namespace epics { namespace pvData {
             words[j] = 0;
     
         for (uint32 remaining = (bytes - longs * 8), j = 0; j < remaining; j++)
-            words[i] |= (buffer->getByte() & 0xffL) << (8 * j);
+            words[i] |= (buffer->getByte() & 0xffLL) << (8 * j);
     
     }