diff -Naur mpfr-2.1.0-p10/rint.c mpfr-2.1.0-p11/rint.c
--- mpfr-2.1.0-p10/rint.c	2004-09-30 16:06:25.000000000 +0000
+++ mpfr-2.1.0-p11/rint.c	2005-01-28 13:52:33.000000000 +0000
@@ -1,6 +1,6 @@
 /* mpfr_rint -- Round to an integer.
 
-Copyright 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
 
 This file is part of the MPFR Library.
 
@@ -205,8 +205,6 @@
           uj = un - ui;  /* lowest limb of the integer part in u */
           rj = rn - ui;  /* lowest limb of the integer part in r */
 
-          MPN_ZERO(rp, rj);
-
           if (rp != up)
             MPN_COPY(rp + rj, up + uj, ui);
 
@@ -270,6 +268,8 @@
                    (sh == 0 && (MPFR_ASSERTN (uj >= 1),
                                 up[uj - 1] & MPFR_LIMB_HIGHBIT) != 0));
             }
+
+          MPN_ZERO (rp-rj, rj);
         }
 
       if (sh != 0)
diff -Naur mpfr-2.1.0-p10/tests/trint.c mpfr-2.1.0-p11/tests/trint.c
--- mpfr-2.1.0-p10/tests/trint.c	2005-01-27 17:38:45.000000000 +0000
+++ mpfr-2.1.0-p11/tests/trint.c	2005-01-28 13:50:56.000000000 +0000
@@ -134,6 +134,19 @@
       exit (1);
     }
 
+  /* Bug found by  Mark J Watkins */
+  mpfr_set_prec (x, 84);
+  mpfr_set_str_binary (x, 
+   "0.110011010010001000000111101101001111111100101110010000000000000" \
+		       "000000000000000000000E32");
+  mpfr_round (x, x);
+  if (mpfr_cmp_str (x, "0.1100110100100010000001111011010100000000000000" \
+		    "00000000000000000000000000000000000000E32", 2, GMP_RNDN))
+    {
+      printf ("Rounding error when dest=src\n");
+      exit (1);
+    }
+
   mpfr_clear (x);
   mpfr_clear (y);
 }