1  /* mpn_cmp -- Compare two low-level natural-number integers.
       2  
       3  Copyright (C) 1991, 1993, 1994, 1996 Free Software Foundation, Inc.
       4  
       5  This file is part of the GNU MP Library.
       6  
       7  The GNU MP Library is free software; you can redistribute it and/or modify
       8  it under the terms of the GNU Lesser General Public License as published by
       9  the Free Software Foundation; either version 2.1 of the License, or (at your
      10  option) any later version.
      11  
      12  The GNU MP Library is distributed in the hope that it will be useful, but
      13  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
      14  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
      15  License for more details.
      16  
      17  You should have received a copy of the GNU Lesser General Public License
      18  along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
      19  the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
      20  MA 02111-1307, USA. */
      21  
      22  #include <config.h>
      23  #include "gmp-impl.h"
      24  
      25  /* Compare OP1_PTR/OP1_SIZE with OP2_PTR/OP2_SIZE.
      26     There are no restrictions on the relative sizes of
      27     the two arguments.
      28     Return 1 if OP1 > OP2, 0 if they are equal, and -1 if OP1 < OP2.  */
      29  
      30  int
      31  #if __STDC__
      32  mpn_cmp (mp_srcptr op1_ptr, mp_srcptr op2_ptr, mp_size_t size)
      33  #else
      34  mpn_cmp (op1_ptr, op2_ptr, size)
      35       mp_srcptr op1_ptr;
      36       mp_srcptr op2_ptr;
      37       mp_size_t size;
      38  #endif
      39  {
      40    mp_size_t i;
      41    mp_limb_t op1_word, op2_word;
      42  
      43    for (i = size - 1; i >= 0; i--)
      44      {
      45        op1_word = op1_ptr[i];
      46        op2_word = op2_ptr[i];
      47        if (op1_word != op2_word)
      48  	goto diff;
      49      }
      50    return 0;
      51   diff:
      52    /* This can *not* be simplified to
      53  	op2_word - op2_word
      54       since that expression might give signed overflow.  */
      55    return (op1_word > op2_word) ? 1 : -1;
      56  }