diff --git a/lisp/lisp.h b/lisp/lisp.h
index dc0a902c4b40badf59b46607083625f558ce1146..9b48af7f4e937c0d7ff210e703a150add24102aa 100644
--- a/lisp/lisp.h
+++ b/lisp/lisp.h
@@ -1,4 +1,4 @@
-/* $Header: /Volumes/share2/src/cmucl/cvs2git/cvsroot/src/lisp/lisp.h,v 1.11 2008/11/12 15:04:24 rtoy Rel $ */
+/* $Header: /Volumes/share2/src/cmucl/cvs2git/cvsroot/src/lisp/lisp.h,v 1.12 2010/10/10 14:54:52 rtoy Exp $ */
 
 #ifndef _LISP_H_
 #define _LISP_H_
@@ -28,8 +28,8 @@ typedef signed int s32;
 typedef u32 lispobj;
 #endif
 
-#define make_fixnum(n) ((lispobj)((n)<<2))
-#define fixnum_value(n) (((long)n)>>2)
+#define make_fixnum(n) ((lispobj)((n)<<(lowtag_Bits-1)))
+#define fixnum_value(n) (((long)n)>>(lowtag_Bits-1))
 
 #define boolean int
 #ifndef TRUE