diff --git a/libguile/pairs.h b/libguile/pairs.h
index 96e6f42cc..e74c855a2 100644
--- a/libguile/pairs.h
+++ b/libguile/pairs.h
@@ -2,7 +2,7 @@
 
 #ifndef PAIRSH
 #define PAIRSH
-/*	Copyright (C) 1995,1996 Free Software Foundation, Inc.
+/*	Copyright (C) 1995,1996, 2000 Free Software Foundation, Inc.
  * 
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -111,10 +111,14 @@ typedef SCM  huge *SCMPTR;
 #define SCM_CARLOC(x) (&SCM_CAR (x))
 #define SCM_CDRLOC(x) (&SCM_CDR (x))
 
-#define SCM_SETAND_CAR(x, y) (SCM_CARW (x) &= (y))
-#define SCM_SETAND_CDR(x, y) (SCM_ASWORD (SCM_CDR (x)) &= (y))
-#define SCM_SETOR_CAR(x, y)  (SCM_CARW (x) |= (y))
-#define SCM_SETOR_CDR(x, y)  (SCM_ASWORD (SCM_CDR (x)) |= (y))
+#define SCM_SETAND_CAR(x, y)\
+  (SCM_CAR (x) = SCM_ASSCM (SCM_ASWORD (SCM_CAR (x)) & (y)))
+#define SCM_SETAND_CDR(x, y)\
+  (SCM_CDR (x) = SCM_ASSCM (SCM_ASWORD (SCM_CDR (x)) & (y)))
+#define SCM_SETOR_CAR(x, y)\
+  (SCM_CAR (x) = SCM_ASSCM (SCM_ASWORD (SCM_CAR (x)) | (y)))
+#define SCM_SETOR_CDR(x, y)\
+  (SCM_CDR (x) = SCM_ASSCM (SCM_ASWORD (SCM_CDR (x)) | (y)))
 
 #define SCM_CAAR(OBJ)		SCM_CAR (SCM_CAR (OBJ))
 #define SCM_CDAR(OBJ)		SCM_CDR (SCM_CAR (OBJ))