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Annotation of OpenXM_contrib/gmp/mpfr/cmp_abs.c, Revision 1.1

1.1     ! ohara       1: /* mpfr_cmp_abs -- compare the absolute values of two nonzero FP numbers
        !             2:
        !             3: Copyright 1999, 2001 Free Software Foundation, Inc.
        !             4:
        !             5: This file is part of the MPFR Library.
        !             6:
        !             7: The MPFR Library is free software; you can redistribute it and/or modify
        !             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
        !            10: option) any later version.
        !            11:
        !            12: The MPFR 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 Lesser General Public
        !            15: License for more details.
        !            16:
        !            17: You should have received a copy of the GNU Lesser General Public License
        !            18: along with the MPFR 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: #include "mpfr.h"
        !            25: #include "mpfr-impl.h"
        !            26:
        !            27: /* returns sign(abs(b) - abs(c))
        !            28:    b and c must be nonzero real numbers */
        !            29:
        !            30: int
        !            31: mpfr_cmp_abs (mpfr_srcptr b, mpfr_srcptr c)
        !            32: {
        !            33:   mp_exp_t be, ce;
        !            34:   mp_size_t bn, cn;
        !            35:   mp_limb_t *bp, *cp;
        !            36:
        !            37:   MPFR_ASSERTN(MPFR_IS_FP(b) && MPFR_NOTZERO(b));
        !            38:   MPFR_ASSERTN(MPFR_IS_FP(c) && MPFR_NOTZERO(c));
        !            39:
        !            40:   be = MPFR_EXP(b);
        !            41:   ce = MPFR_EXP(c);
        !            42:   if (be > ce)
        !            43:     return 1;
        !            44:   if (be < ce)
        !            45:     return -1;
        !            46:
        !            47:   /* exponents are equal */
        !            48:
        !            49:   bn = (MPFR_PREC(b)-1)/BITS_PER_MP_LIMB;
        !            50:   cn = (MPFR_PREC(c)-1)/BITS_PER_MP_LIMB;
        !            51:
        !            52:   bp = MPFR_MANT(b);
        !            53:   cp = MPFR_MANT(c);
        !            54:
        !            55:   for ( ; bn >= 0 && cn >= 0; bn--, cn--)
        !            56:     {
        !            57:       if (bp[bn] > cp[cn])
        !            58:         return 1;
        !            59:       if (bp[bn] < cp[cn])
        !            60:         return -1;
        !            61:     }
        !            62:
        !            63:   for ( ; bn >= 0; bn--)
        !            64:     if (bp[bn])
        !            65:       return 1;
        !            66:
        !            67:   for ( ; cn >= 0; cn--)
        !            68:     if (cp[cn])
        !            69:       return -1;
        !            70:
        !            71:    return 0;
        !            72: }