1  /* mpf_cmp_ui -- Compare a float with an unsigned integer.
       2  
       3  Copyright 1993-1995, 1999, 2001, 2002, 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_ui (mpf_srcptr u, unsigned long int vval) __GMP_NOTHROW
      35  {
      36    mp_srcptr up;
      37    mp_size_t usize;
      38    mp_exp_t uexp;
      39    mp_limb_t ulimb;
      40  
      41    usize = SIZ (u);
      42  
      43    /* 1. Is U negative?  */
      44    if (usize < 0)
      45      return -1;
      46    /* We rely on usize being non-negative in the code that follows.  */
      47  
      48    if (vval == 0)
      49      return usize != 0;
      50  
      51    /* 2. Are the exponents different (V's exponent == 1)?  */
      52    uexp = EXP (u);
      53  
      54  #if GMP_NAIL_BITS != 0
      55    if (uexp != 1 + (vval > GMP_NUMB_MAX))
      56      return (uexp < 1 + (vval > GMP_NUMB_MAX)) ? -1 : 1;
      57  #else
      58    if (uexp != 1)
      59      return (uexp < 1) ? -1 : 1;
      60  #endif
      61  
      62    up = PTR (u);
      63  
      64    ASSERT (usize > 0);
      65    ulimb = up[--usize];
      66  #if GMP_NAIL_BITS != 0
      67    if (uexp == 2)
      68      {
      69        if ((ulimb >> GMP_NAIL_BITS) != 0)
      70  	return 1;
      71        ulimb = (ulimb << GMP_NUMB_BITS);
      72        if (usize != 0) ulimb |= up[--usize];
      73      }
      74  #endif
      75  
      76    /* 3. Compare the most significant mantissa limb with V.  */
      77    if (ulimb != vval)
      78      return (ulimb < vval) ? -1 : 1;
      79  
      80    /* Ignore zeroes at the low end of U.  */
      81    for (; *up == 0; ++up)
      82      --usize;
      83  
      84    /* 4. Now, if the number of limbs are different, we have a difference
      85       since we have made sure the trailing limbs are not zero.  */
      86    return (usize > 0);
      87  }