1  /* mpf_cmp -- Compare two floats.
       2  
       3  Copyright 1993, 1994, 1996, 2001, 2015 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 either:
       9  
      10    * the GNU Lesser General Public License as published by the Free
      11      Software Foundation; either version 3 of the License, or (at your
      12      option) any later version.
      13  
      14  or
      15  
      16    * the GNU General Public License as published by the Free Software
      17      Foundation; either version 2 of the License, or (at your option) any
      18      later version.
      19  
      20  or both in parallel, as here.
      21  
      22  The GNU MP Library is distributed in the hope that it will be useful, but
      23  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
      24  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
      25  for more details.
      26  
      27  You should have received copies of the GNU General Public License and the
      28  GNU Lesser General Public License along with the GNU MP Library.  If not,
      29  see https://www.gnu.org/licenses/.  */
      30  
      31  #include "gmp-impl.h"
      32  
      33  int
      34  mpf_cmp (mpf_srcptr u, mpf_srcptr v) __GMP_NOTHROW
      35  {
      36    mp_srcptr up, vp;
      37    mp_size_t usize, vsize;
      38    mp_exp_t uexp, vexp;
      39    int cmp;
      40    int usign;
      41  
      42    usize = SIZ(u);
      43    vsize = SIZ(v);
      44    usign = usize >= 0 ? 1 : -1;
      45  
      46    /* 1. Are the signs different?  */
      47    if ((usize ^ vsize) >= 0)
      48      {
      49        /* U and V are both non-negative or both negative.  */
      50        if (usize == 0)
      51  	/* vsize >= 0 */
      52  	return -(vsize != 0);
      53        if (vsize == 0)
      54  	/* usize >= 0 */
      55  	return usize != 0;
      56        /* Fall out.  */
      57      }
      58    else
      59      {
      60        /* Either U or V is negative, but not both.  */
      61        return usign;
      62      }
      63  
      64    /* U and V have the same sign and are both non-zero.  */
      65  
      66    uexp = EXP(u);
      67    vexp = EXP(v);
      68  
      69    /* 2. Are the exponents different?  */
      70    if (uexp > vexp)
      71      return usign;
      72    if (uexp < vexp)
      73      return -usign;
      74  
      75    usize = ABS (usize);
      76    vsize = ABS (vsize);
      77  
      78    up = PTR (u);
      79    vp = PTR (v);
      80  
      81  #define STRICT_MPF_NORMALIZATION 0
      82  #if ! STRICT_MPF_NORMALIZATION
      83    /* Ignore zeroes at the low end of U and V.  */
      84    do {
      85      mp_limb_t tl;
      86      tl = up[0];
      87      MPN_STRIP_LOW_ZEROS_NOT_ZERO (up, usize, tl);
      88      tl = vp[0];
      89      MPN_STRIP_LOW_ZEROS_NOT_ZERO (vp, vsize, tl);
      90    } while (0);
      91  #endif
      92  
      93    if (usize > vsize)
      94      {
      95        cmp = mpn_cmp (up + usize - vsize, vp, vsize);
      96        /* if (cmp == 0) */
      97        /*	return usign; */
      98        ++cmp;
      99      }
     100    else if (vsize > usize)
     101      {
     102        cmp = mpn_cmp (up, vp + vsize - usize, usize);
     103        /* if (cmp == 0) */
     104        /*	return -usign; */
     105      }
     106    else
     107      {
     108        cmp = mpn_cmp (up, vp, usize);
     109        if (cmp == 0)
     110  	return 0;
     111      }
     112    return cmp > 0 ? usign : -usign;
     113  }