diff --git a/defs.h b/defs.h
index 01f316e..4d8ebc9 100644
--- a/defs.h
+++ b/defs.h
@@ -4842,7 +4842,11 @@ struct machine_specific {
 #define UNINITIALIZED (BADVAL)
 
 #define BITS_PER_BYTE (8)
-#define BITS_PER_LONG (BITS_PER_BYTE * sizeof(long))
+#ifdef _64BIT_
+#define BITS_PER_LONG (64)
+#else
+#define BITS_PER_LONG (32)
+#endif