diff --git a/mps/src/mpm.c b/mps/src/mpm.c
index 8380c57f6e2..8c6acd90c80 100644
--- a/mps/src/mpm.c
+++ b/mps/src/mpm.c
@@ -1,6 +1,6 @@
 /* impl.c.mpm: GENERAL MPM SUPPORT
  *
- * $HopeName: MMsrc!mpm.c(trunk.13) $
+ * $HopeName: MMsrc!mpm.c(trunk.14) $
  * Copyright (C) 1996 Harlequin Group, all rights reserved.
  *
  * .readership: MM developers.
@@ -13,7 +13,7 @@
 
 #include "mpm.h"
 
-SRCID(mpm, "$HopeName: MMsrc!mpm.c(trunk.13) $");
+SRCID(mpm, "$HopeName: MMsrc!mpm.c(trunk.14) $");
 
 
 /* MPMCheck -- test MPM assumptions */
@@ -80,6 +80,15 @@ Bool FunCheck(Fun f)
 }
 
 
+/* ShiftCheck -- check that a shift is valid */
+
+Bool ShiftCheck(Shift shift)
+{
+  AVER(shift < MPS_WORD_WIDTH);         /* standard.ansic 6.3.7 */
+  return TRUE;
+}
+
+
 /* AttrCheck -- check that a set of pool attributes are valid */
 
 Bool AttrCheck(Attr attr)