/*
    Copyright (C) 2009, 2016 William Hart

    This file is part of FLINT.

    FLINT is free software: you can redistribute it and/or modify it under
    the terms of the GNU Lesser General Public License (LGPL) as published
    by the Free Software Foundation; either version 2.1 of the License, or
    (at your option) any later version.  See <https://www.gnu.org/licenses/>.
*/

#include <gmp.h>
#include "flint.h"
#include "ulong_extras.h"

int main(void)
{
   int i, result;
   FLINT_TEST_INIT(state);
   
   flint_printf("mulmod2_preinv....");
   fflush(stdout);

   for (i = 0; i < 100000 * flint_test_multiplier(); i++)
   {
      ulong a, b, d, r1, r2, q, p1, p2, dinv;
      
      d = n_randtest_not_zero(state);
      a = n_randtest(state) % d;
      b = n_randtest(state) % d;
      
      dinv = n_preinvert_limb(d);

      r1 = n_mulmod2_preinv(a, b, d, dinv);

      umul_ppmm(p1, p2, a, b);
      p1 %= d;
      udiv_qrnnd(q, r2, p1, p2, d); 
      
      result = (r1 == r2);
      if (!result)
      {
         flint_printf("FAIL:\n");
         flint_printf("a = %wu, b = %wu, d = %wu, dinv = %wu\n", a, b, d, dinv); 
         flint_printf("q = %wu, r1 = %wu, r2 = %wu\n", q, r1, r2);
         abort();
      }
   }

   FLINT_TEST_CLEANUP(state);
   
   flint_printf("PASS\n");
   return 0;
}