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Annotation of OpenXM_contrib/gmp/mpf/cmp_ui.c, Revision 1.1.1.3

1.1       maekawa     1: /* mpf_cmp_ui -- Compare a float with an unsigned integer.
                      2:
1.1.1.3 ! ohara       3: Copyright 1993, 1994, 1995, 1999, 2001, 2002 Free Software Foundation, Inc.
1.1       maekawa     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
1.1.1.2   maekawa     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
1.1       maekawa    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
1.1.1.2   maekawa    14: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
1.1       maekawa    15: License for more details.
                     16:
1.1.1.2   maekawa    17: You should have received a copy of the GNU Lesser General Public License
1.1       maekawa    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 "gmp.h"
                     23: #include "gmp-impl.h"
                     24:
                     25: int
1.1.1.3 ! ohara      26: mpf_cmp_ui (mpf_srcptr u, unsigned long int vval)
1.1       maekawa    27: {
                     28:   mp_srcptr up;
                     29:   mp_size_t usize;
                     30:   mp_exp_t uexp;
1.1.1.3 ! ohara      31:   mp_limb_t ulimb;
1.1       maekawa    32:
                     33:   uexp = u->_mp_exp;
                     34:   usize = u->_mp_size;
                     35:
                     36:   /* 1. Is U negative?  */
                     37:   if (usize < 0)
                     38:     return -1;
                     39:   /* We rely on usize being non-negative in the code that follows.  */
                     40:
1.1.1.3 ! ohara      41:   if (vval == 0)
1.1       maekawa    42:     return usize != 0;
                     43:
                     44:   /* 2. Are the exponents different (V's exponent == 1)?  */
1.1.1.3 ! ohara      45: #if GMP_NAIL_BITS != 0
        !            46:   if (uexp > 1 + (vval > GMP_NUMB_MAX))
        !            47:     return 1;
        !            48:   if (uexp < 1 + (vval > GMP_NUMB_MAX))
        !            49:     return -1;
        !            50: #else
1.1       maekawa    51:   if (uexp > 1)
                     52:     return 1;
                     53:   if (uexp < 1)
                     54:     return -1;
1.1.1.3 ! ohara      55: #endif
1.1       maekawa    56:
                     57:   up = u->_mp_d;
                     58:
1.1.1.3 ! ohara      59:   ulimb = up[usize - 1];
        !            60: #if GMP_NAIL_BITS != 0
        !            61:   if (usize >= 2 && uexp == 2)
        !            62:     {
        !            63:       if ((ulimb >> GMP_NAIL_BITS) != 0)
        !            64:        return 1;
        !            65:       ulimb = (ulimb << GMP_NUMB_BITS) | up[usize - 2];
        !            66:       usize--;
        !            67:     }
        !            68: #endif
        !            69:   usize--;
        !            70:
1.1.1.2   maekawa    71:   /* 3. Compare the most significant mantissa limb with V.  */
1.1.1.3 ! ohara      72:   if (ulimb > vval)
1.1.1.2   maekawa    73:     return 1;
1.1.1.3 ! ohara      74:   else if (ulimb < vval)
1.1.1.2   maekawa    75:     return -1;
                     76:
1.1       maekawa    77:   /* Ignore zeroes at the low end of U.  */
                     78:   while (*up == 0)
                     79:     {
                     80:       up++;
                     81:       usize--;
                     82:     }
                     83:
1.1.1.2   maekawa    84:   /* 4. Now, if the number of limbs are different, we have a difference
1.1       maekawa    85:      since we have made sure the trailing limbs are not zero.  */
1.1.1.3 ! ohara      86:   if (usize > 0)
1.1       maekawa    87:     return 1;
                     88:
                     89:   /* Wow, we got zero even if we tried hard to avoid it.  */
                     90:   return 0;
                     91: }