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Annotation of OpenXM_contrib/gmp/mpf/cmp_si.c, Revision 1.1.1.1

1.1       maekawa     1: /* mpf_cmp_si -- Compare a float with a signed integer.
                      2:
                      3: Copyright (C) 1993, 1994, 1995 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 Library General Public License as published by
                      9: the Free Software Foundation; either version 2 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 Library General Public
                     15: License for more details.
                     16:
                     17: You should have received a copy of the GNU Library 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 "gmp.h"
                     23: #include "gmp-impl.h"
                     24:
                     25: int
                     26: #if __STDC__
                     27: mpf_cmp_si (mpf_srcptr u, long int vslimb)
                     28: #else
                     29: mpf_cmp_si (u, vslimb)
                     30:      mpf_srcptr u;
                     31:      long int vslimb;
                     32: #endif
                     33: {
                     34:   mp_srcptr up;
                     35:   mp_size_t usize;
                     36:   mp_exp_t uexp;
                     37:   int usign;
                     38:
                     39:   uexp = u->_mp_exp;
                     40:   usize = u->_mp_size;
                     41:
                     42:   /* 1. Are the signs different?  */
                     43:   if ((usize < 0) == (vslimb < 0)) /* don't use xor, type size may differ */
                     44:     {
                     45:       /* U and V are both non-negative or both negative.  */
                     46:       if (usize == 0)
                     47:        /* vslimb >= 0 */
                     48:        return -(vslimb != 0);
                     49:       if (vslimb == 0)
                     50:        /* usize >= 0 */
                     51:        return usize != 0;
                     52:       /* Fall out.  */
                     53:     }
                     54:   else
                     55:     {
                     56:       /* Either U or V is negative, but not both.  */
                     57:       return usize >= 0 ? 1 : -1;
                     58:     }
                     59:
                     60:   /* U and V have the same sign and are both non-zero.  */
                     61:
                     62:   usign = usize >= 0 ? 1 : -1;
                     63:
                     64:   /* 2. Are the exponents different (V's exponent == 1)?  */
                     65:   if (uexp > 1)
                     66:     return usign;
                     67:   if (uexp < 1)
                     68:     return -usign;
                     69:
                     70:   usize = ABS (usize);
                     71:   vslimb = ABS (vslimb);
                     72:
                     73:   up = u->_mp_d;
                     74:
                     75: #define STRICT_MPF_NORMALIZATION 0
                     76: #if ! STRICT_MPF_NORMALIZATION
                     77:   /* Ignore zeroes at the low end of U and V.  */
                     78:   while (*up == 0)
                     79:     {
                     80:       up++;
                     81:       usize--;
                     82:     }
                     83: #endif
                     84:
                     85:   /* 3. Now, if the number of limbs are different, we have a difference
                     86:      since we have made sure the trailing limbs are not zero.  */
                     87:   if (usize > 1)
                     88:     return usign;
                     89:
                     90:   /* 4. Compare the mantissas.  */
                     91:   if (*up > vslimb)
                     92:     return usign;
                     93:   else if (*up < vslimb)
                     94:     return -usign;
                     95:
                     96:   /* Wow, we got zero even if we tried hard to avoid it.  */
                     97:   return 0;
                     98: }