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Annotation of OpenXM_contrib/gmp/mpf/cmp_si.c, Revision 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: }