diff --git a/tests/mpn/t-inv_divappr_q_n.c b/tests/mpn/t-inv_divappr_q_n.c
new file mode 100644
index 00000000..76e391ab
--- /dev/null
+++ b/tests/mpn/t-inv_divappr_q_n.c
@@ -0,0 +1,125 @@
+/* Test mpn_inv_divappr_q_n.
+
+Copyright 2002 Free Software Foundation, Inc.
+Copyright 2009, 2010 William Hart
+
+This file is part of the MPIR Library.
+
+The MPIR Library is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or (at your
+option) any later version.
+
+The MPIR Library is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
+License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with the MPIR Library; see the file COPYING.LIB.  If not, write to
+the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+MA 02110-1301, USA. */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "mpir.h"
+#include "gmp-impl.h"
+#include "longlong.h"
+#include "tests.h"
+
+#if defined(_MSC_VER) || defined(__MINGW32__)
+#define random rand
+#endif
+
+#define MAX_LIMBS 200
+#define ITERS 2000
+   
+/* Check divide and conquer division routine. */
+void
+check_inv_divappr_q_n (void)
+{
+   mp_limb_t np[2*MAX_LIMBS];
+   mp_limb_t np2[2*MAX_LIMBS];
+   mp_limb_t rp[2*MAX_LIMBS];
+   mp_limb_t dp[MAX_LIMBS];
+   mp_limb_t qp[MAX_LIMBS];
+   mp_limb_t dip[MAX_LIMBS];
+
+   mp_size_t nn, rn, dn, qn;
+
+   gmp_randstate_t rands;
+
+   int i, j, s;
+   gmp_randinit_default(rands);
+  
+   for (i = 0; i < ITERS; i++)
+   {
+      dn = (random() % (MAX_LIMBS - 6)) + 6;
+      nn = 2*dn;
+         
+      mpn_rrandom (np, rands, nn);
+      mpn_rrandom (dp, rands, dn);
+      dp[dn-1] |= GMP_LIMB_HIGHBIT;
+
+      MPN_COPY(np2, np, nn);
+      
+      mpn_invert(dip, dp, dn);
+
+      qn = nn - dn + 1;
+         
+      qp[qn - 1] = mpn_inv_divappr_q_n(qp, np, dp, dn, dip);
+      
+      MPN_NORMALIZE(qp, qn);
+
+      if (qn)
+      {
+         if (qn >= dn) mpn_mul(rp, qp, qn, dp, dn);
+         else mpn_mul(rp, dp, dn, qp, qn);
+
+         rn = dn + qn;
+         MPN_NORMALIZE(rp, rn);
+
+         s = (rn < nn) ? -1 : (rn > nn) ? 1 : mpn_cmp(rp, np2, nn);
+         if (s <= 0) 
+         {
+            mpn_sub(rp, np2, nn, rp, rn);
+            rn = nn;
+            MPN_NORMALIZE(rp, rn);
+         } else 
+         {
+            mpn_sub(rp, rp, rn, np2, nn);
+            MPN_NORMALIZE(rp, rn);
+         }
+      } else
+      {
+         rn = nn;
+         MPN_COPY(rp, np, nn);
+      }
+      
+      s = (rn < dn) ? -1 : (rn > dn) ? 1 : mpn_cmp(rp, dp, dn);
+      if (s >= 0)
+      {
+         printf ("failed:\n");
+         printf ("nn = %lu, dn = %lu, qn = %lu, rn = %lu\n\n", nn, dn, qn, rn);
+         gmp_printf (" np: %Nx\n\n", np2, nn);
+         gmp_printf (" dp: %Nx\n\n", dp, dn);
+         gmp_printf (" qp: %Nx\n\n", qp, qn);
+         gmp_printf (" rp: %Nx\n\n", rp, rn);
+         abort ();
+      }
+   }
+
+   gmp_randclear(rands);
+}
+
+int
+main (void)
+{
+  tests_start ();
+
+  check_inv_divappr_q_n ();
+  
+  tests_end ();
+  exit (0);
+}