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Annotation of OpenXM_contrib/gmp/mpf/cmp.c, Revision 1.1

1.1     ! maekawa     1: /* mpf_cmp -- Compare two floats.
        !             2:
        !             3: Copyright (C) 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 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 (mpf_srcptr u, mpf_srcptr v)
        !            28: #else
        !            29: mpf_cmp (u, v)
        !            30:      mpf_srcptr u;
        !            31:      mpf_srcptr v;
        !            32: #endif
        !            33: {
        !            34:   mp_srcptr up, vp;
        !            35:   mp_size_t usize, vsize;
        !            36:   mp_exp_t uexp, vexp;
        !            37:   int cmp;
        !            38:   int usign;
        !            39:
        !            40:   uexp = u->_mp_exp;
        !            41:   vexp = v->_mp_exp;
        !            42:
        !            43:   usize = u->_mp_size;
        !            44:   vsize = v->_mp_size;
        !            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 usize >= 0 ? 1 : -1;
        !            62:     }
        !            63:
        !            64:   /* U and V have the same sign and are both non-zero.  */
        !            65:
        !            66:   usign = usize >= 0 ? 1 : -1;
        !            67:
        !            68:   /* 2. Are the exponents different?  */
        !            69:   if (uexp > vexp)
        !            70:     return usign;
        !            71:   if (uexp < vexp)
        !            72:     return -usign;
        !            73:
        !            74:   usize = ABS (usize);
        !            75:   vsize = ABS (vsize);
        !            76:
        !            77:   up = u->_mp_d;
        !            78:   vp = v->_mp_d;
        !            79:
        !            80: #define STRICT_MPF_NORMALIZATION 0
        !            81: #if ! STRICT_MPF_NORMALIZATION
        !            82:   /* Ignore zeroes at the low end of U and V.  */
        !            83:   while (up[0] == 0)
        !            84:     {
        !            85:       up++;
        !            86:       usize--;
        !            87:     }
        !            88:   while (vp[0] == 0)
        !            89:     {
        !            90:       vp++;
        !            91:       vsize--;
        !            92:     }
        !            93: #endif
        !            94:
        !            95:   if (usize > vsize)
        !            96:     {
        !            97:       cmp = mpn_cmp (up + usize - vsize, vp, vsize);
        !            98:       if (cmp == 0)
        !            99:        return usign;
        !           100:     }
        !           101:   else if (vsize > usize)
        !           102:     {
        !           103:       cmp = mpn_cmp (up, vp + vsize - usize, usize);
        !           104:       if (cmp == 0)
        !           105:        return -usign;
        !           106:     }
        !           107:   else
        !           108:     {
        !           109:       cmp = mpn_cmp (up, vp, usize);
        !           110:       if (cmp == 0)
        !           111:        return 0;
        !           112:     }
        !           113:   return cmp > 0 ? usign : -usign;
        !           114: }