1  /* Test mpn_gcdext_1.
       2  
       3  Copyright 2019 Free Software Foundation, Inc.
       4  
       5  This file is part of the GNU MP Library test suite.
       6  
       7  The GNU MP Library test suite is free software; you can redistribute it
       8  and/or modify it under the terms of the GNU General Public License as
       9  published by the Free Software Foundation; either version 3 of the License,
      10  or (at your option) any later version.
      11  
      12  The GNU MP Library test suite is distributed in the hope that it will be
      13  useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
      14  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
      15  Public License for more details.
      16  
      17  You should have received a copy of the GNU General Public License along with
      18  the GNU MP Library test suite.  If not, see https://www.gnu.org/licenses/.  */
      19  
      20  #include <stdio.h>
      21  #include <stdlib.h>
      22  
      23  #include "gmp-impl.h"
      24  #include "tests.h"
      25  
      26  #ifndef COUNT
      27  #define COUNT 250000
      28  #endif
      29  
      30  static void
      31  set_signed_limb (mpz_t r, mp_limb_signed_t x)
      32  {
      33    mpz_t t;
      34    mp_limb_t abs_x = ABS_CAST(mp_limb_t, x);
      35    mpz_set (r, mpz_roinit_n (t, &abs_x, 1));
      36    if (x < 0)
      37      mpz_neg (r, r);
      38  }
      39  
      40  static void
      41  one_test (mp_limb_t a, mp_limb_t b)
      42  {
      43    mp_limb_signed_t s, t;
      44    mp_limb_t g;
      45  
      46    g = mpn_gcdext_1 (&s, &t, a, b);
      47  
      48    if (g > 0)
      49      {
      50        mpz_t d, sz, tz, tmp;
      51  
      52        mpz_init (d);
      53        mpz_init (sz);
      54        mpz_init (tz);
      55  
      56        set_signed_limb (sz, s);
      57        set_signed_limb (tz, t);
      58  
      59        mpz_mul (d, mpz_roinit_n (tmp, &a, 1), sz);
      60        mpz_addmul (d, mpz_roinit_n (tmp, &b, 1), tz);
      61  
      62        if (mpz_cmp (d, mpz_roinit_n (tmp, &g, 1)) == 0
      63  	  && a % g == 0 && b % g == 0)
      64  	{
      65  	  mp_limb_t a_div_g = a / g;
      66  	  mp_limb_t b_div_g = b / g;
      67  	  mp_limb_t abs_s = ABS_CAST(mp_limb_t, s);
      68  	  mp_limb_t abs_t = ABS_CAST(mp_limb_t, t);
      69  	  mpz_mul_ui (sz, sz, 2);
      70  	  mpz_mul_ui (tz, tz, 2);
      71  	  if ((abs_s == 1 || mpz_cmpabs (sz, mpz_roinit_n (tmp, &b_div_g, 1)) < 0)
      72  	       && (abs_t == 1 || mpz_cmpabs (tz, mpz_roinit_n (tmp, &a_div_g, 1)) < 0))
      73  	    {
      74  	      mpz_clear (d);
      75  	      mpz_clear (sz);
      76  	      mpz_clear (tz);
      77  
      78  	      return;
      79  	    }
      80  	}
      81      }
      82    gmp_fprintf (stderr,
      83  	       "gcdext_1 (0x%Mx, 0x%Mx) failed, got: g = 0x%Mx, s = %s0x%Mx, t = %s0x%Mx\n",
      84  	       a, b, g,
      85  	       s < 0 ? "-" : "", ABS_CAST(mp_limb_t, s),
      86  	       t < 0 ? "-" : "", ABS_CAST(mp_limb_t, t));
      87    abort();
      88  }
      89  
      90  int
      91  main (int argc, char **argv)
      92  {
      93    mpz_t a, b;
      94    int count = COUNT;
      95    int test;
      96    gmp_randstate_ptr rands;
      97  
      98    TESTS_REPS (count, argv, argc);
      99  
     100    tests_start ();
     101    rands = RANDS;
     102  
     103    mpz_init (a);
     104    mpz_init (b);
     105    for (test = 0; test < count; test++)
     106      {
     107        mp_limb_t al, bl;
     108        mp_bitcnt_t asize = 1 + gmp_urandomm_ui(rands, GMP_NUMB_BITS);
     109        mp_bitcnt_t bsize = 1 + gmp_urandomm_ui(rands, GMP_NUMB_BITS);
     110        if (test & 1)
     111  	{
     112  	  mpz_urandomb (a, rands, asize);
     113  	  mpz_urandomb (b, rands, bsize);
     114  	}
     115        else
     116  	{
     117  	  mpz_rrandomb (a, rands, asize);
     118  	  mpz_rrandomb (b, rands, bsize);
     119  	}
     120  
     121        al = mpz_getlimbn (a, 0);
     122        bl = mpz_getlimbn (b, 0);
     123        al += (al == 0);
     124        bl += (bl == 0);
     125  
     126        one_test (al, bl);
     127      }
     128  
     129    mpz_clear (a);
     130    mpz_clear (b);
     131  
     132    tests_end ();
     133    return 0;
     134  }