Fix overrun in @mpx_lsr@.

diff --git a/mpx.c b/mpx.c
index 1591f98..ef93e3e 100644 (file)
--- a/mpx.c
+++ b/mpx.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
 /* -*-c-*-
  *

- * $Id: mpx.c,v 1.18 2004/04/01 12:50:09 mdw Exp $
+ * $Id: mpx.c,v 1.19 2004/04/03 03:29:40 mdw Exp $

  *
  * Low-level multiprecision arithmetic
  *
  *
  * Low-level multiprecision arithmetic
  *


@@ -30,6 +30,9 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: mpx.c,v $
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: mpx.c,v $

+ * Revision 1.19  2004/04/03 03:29:40  mdw
+ * Fix overrun in @mpx_lsr@.
+ *

  * Revision 1.18  2004/04/01 12:50:09  mdw
  * Add cyclic group abstraction, with test code.  Separate off exponentation
  * functions for better static linking.  Fix a buttload of bugs on the way.
  * Revision 1.18  2004/04/01 12:50:09  mdw
  * Add cyclic group abstraction, with test code.  Separate off exponentation
  * functions for better static linking.  Fix a buttload of bugs on the way.


@@ -660,7 +663,7 @@ void mpx_lsr(mpw *dv, mpw *dvl, const mpw *av, const mpw *avl, size_t n)
   /* --- Single bit shifting --- */
 
   else if (n == 1) {
   /* --- Single bit shifting --- */
 
   else if (n == 1) {

-    mpw w = *av++ >> 1;
+    mpw w = av < avl ? *av++ >> 1 : 0;

     while (av < avl) {
       mpw t;
       if (dv >= dvl)
     while (av < avl) {
       mpw t;
       if (dv >= dvl)