gcc/gmp/mpz/cmp_ui.c

/* mpz_cmp_ui.c -- Compare a mpz_t a with an mp_limb_t b.  Return positive,
  zero, or negative based on if a > b, a == b, or a < b.

Copyright 1991, 1993, 1994, 1995, 1996, 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_ui (mpz_srcptr u, unsigned long int v_digit)
{
  mp_ptr up;
  mp_size_t un;
  mp_limb_t ul;

  up = PTR(u);
  un = SIZ(u);

  if (un == 0)
    return -(v_digit != 0);

  if (un == 1)
    {
      ul = up[0];
      if (ul > v_digit)
	return 1;
      if (ul < v_digit)
	return -1;
      return 0;
    }

#if GMP_NAIL_BITS != 0
  if (v_digit > GMP_NUMB_MAX)
    {
      if (un == 2)
	{
	  ul = up[0] + (up[1] << GMP_NUMB_BITS);

	  if ((up[1] >> GMP_NAIL_BITS) != 0)
	    return 1;

	  if (ul > v_digit)
	    return 1;
	  if (ul < v_digit)
	    return -1;
	  return 0;
	}
    }
#endif

  return un > 0 ? 1 : -1;
}