xref: /dragonfly/contrib/gmp/mpz/cmp_si.c (revision d2d4b659)

/* mpz_cmp_si(u,v) -- Compare an integer U with a single-word int V.
   Return positive, zero, or negative based on if U > V, U == V, or U < V.

Copyright 1991, 1993, 1994, 1995, 1996, 2000, 2001, 2002 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 3 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.  If not, see http://www.gnu.org/licenses/.  */

#include "gmp.h"
#include "gmp-impl.h"

int
_mpz_cmp_si (mpz_srcptr u, signed long int v_digit) __GMP_NOTHROW
{
  mp_size_t usize = u->_mp_size;
  mp_size_t vsize;
  mp_limb_t u_digit;
  unsigned long int absv_digit = (unsigned long int) v_digit;

#if GMP_NAIL_BITS != 0
  /* FIXME.  This isn't very pretty.  */
  mpz_t tmp;
  mp_limb_t tt[2];
  PTR(tmp) = tt;
  ALLOC(tmp) = 2;
  mpz_set_si (tmp, v_digit);
  return mpz_cmp (u, tmp);
#endif

  vsize = 0;
  if (v_digit > 0)
    vsize = 1;
  else if (v_digit < 0)
    {
      vsize = -1;
      absv_digit = -absv_digit;
    }

  if (usize != vsize)
    return usize - vsize;

  if (usize == 0)
    return 0;

  u_digit = u->_mp_d[0];

  if (u_digit == (mp_limb_t) absv_digit)
    return 0;

  if (u_digit > (mp_limb_t) absv_digit)
    return usize;
  else
    return -usize;
}