mpir/tests/mpn/t-divrem_1.c

/* Test mpn_divrem_1 and mpn_preinv_divrem_1.

Copyright 2003 Free Software Foundation, Inc.

This file is part of the GNU MP Library.

The GNU MP 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 GNU MP 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 GNU MP 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 "tests.h"


void
check_data (void)
{
  static const struct {
    mp_limb_t  n[1];
    mp_size_t  nsize;
    mp_limb_t  d;
    mp_size_t  qxn;
    mp_limb_t  want_q[5];
    mp_limb_t  want_r;
  } data[] = {
    { { 0 }, 1, 1, 0,
      { 0 }, 0},

    { { 5 }, 1, 2, 0,
      { 2 }, 1},

#if GMP_NUMB_BITS == 32
    { { 0x3C }, 1, 0xF2, 1,
      { 0x3F789854, 0 }, 0x98 },
#endif

#if GMP_NUMB_BITS == 64
    { { 0x3C }, 1, 0xF2, 1,
      { CNST_LIMB(0x3F789854A0CB1B81), 0 }, 0x0E },

    /* This case exposed some wrong code generated by SGI cc on mips64 irix
       6.5 with -n32 -O2, in the fractional loop for normalized divisor
       using udiv_qrnnd_preinv.  A test "x>al" in one of the sub_ddmmss
       expansions came out wrong, leading to an incorrect quotient.  */
    { { CNST_LIMB(0x3C00000000000000) }, 1, CNST_LIMB(0xF200000000000000), 1,
      { CNST_LIMB(0x3F789854A0CB1B81), 0 }, CNST_LIMB(0x0E00000000000000) },
#endif
  };

  mp_limb_t  dinv, got_r, got_q[numberof(data[0].want_q)];
  mp_size_t  qsize;
  int        i, shift;

  for (i = 0; i < numberof (data); i++)
    {
      qsize = data[i].nsize + data[i].qxn;
      ASSERT_ALWAYS (qsize <= numberof (got_q));

      got_r = mpn_divrem_1 (got_q, data[i].qxn, data[i].n, data[i].nsize,
                            data[i].d);
      if (got_r != data[i].want_r
          || refmpn_cmp (got_q, data[i].want_q, qsize) != 0)
        {
          printf        ("mpn_divrem_1 wrong at data[%d]\n", i);
        bad:
          mpn_trace     ("  n", data[i].n, data[i].nsize);
          printf        ("  nsize=%ld\n", (long) data[i].nsize);
          mp_limb_trace ("  d", data[i].d);
          printf        ("  qxn=%ld\n", (long) data[i].qxn);
          mpn_trace     ("  want q", data[i].want_q, qsize);
          mpn_trace     ("  got  q", got_q, qsize);
          mp_limb_trace ("  want r", data[i].want_r);
          mp_limb_trace ("  got  r", got_r);
          abort ();
        }

      /* test if available */
#if USE_PREINV_DIVREM_1 || HAVE_NATIVE_mpn_preinv_divrem_1
      shift = refmpn_count_leading_zeros (data[i].d);
      dinv = refmpn_invert_limb (data[i].d << shift);
      got_r = mpn_preinv_divrem_1 (got_q, data[i].qxn,
                                   data[i].n, data[i].nsize,
                                   data[i].d, dinv, shift);
      if (got_r != data[i].want_r
          || refmpn_cmp (got_q, data[i].want_q, qsize) != 0)
        {
          printf        ("mpn_preinv_divrem_1 wrong at data[%d]\n", i);
          printf        ("  shift=%d\n", shift);
          mp_limb_trace ("  dinv", dinv);
          goto bad;
        }
#endif
    }
}

int
main (void)
{
  tests_start ();
  mp_trace_base = -16;

  check_data ();

  tests_end ();
  exit (0);
}