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

1.1     ! maekawa     1: /* mpf_mul -- Multiply 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: void
        !            26: #if __STDC__
        !            27: mpf_mul (mpf_ptr r, mpf_srcptr u, mpf_srcptr v)
        !            28: #else
        !            29: mpf_mul (r, u, v)
        !            30:      mpf_ptr r;
        !            31:      mpf_srcptr u;
        !            32:      mpf_srcptr v;
        !            33: #endif
        !            34: {
        !            35:   mp_srcptr up, vp;
        !            36:   mp_size_t usize, vsize;
        !            37:   mp_size_t sign_product;
        !            38:   mp_size_t prec = r->_mp_prec;
        !            39:   TMP_DECL (marker);
        !            40:
        !            41:   TMP_MARK (marker);
        !            42:   usize = u->_mp_size;
        !            43:   vsize = v->_mp_size;
        !            44:   sign_product = usize ^ vsize;
        !            45:
        !            46:   usize = ABS (usize);
        !            47:   vsize = ABS (vsize);
        !            48:
        !            49:   up = u->_mp_d;
        !            50:   vp = v->_mp_d;
        !            51:   if (usize > prec)
        !            52:     {
        !            53:       up += usize - prec;
        !            54:       usize = prec;
        !            55:     }
        !            56:   if (vsize > prec)
        !            57:     {
        !            58:       vp += vsize - prec;
        !            59:       vsize = prec;
        !            60:     }
        !            61:
        !            62:   if (usize == 0 || vsize == 0)
        !            63:     {
        !            64:       r->_mp_size = 0;
        !            65:       r->_mp_exp = 0;          /* ??? */
        !            66:     }
        !            67:   else
        !            68:     {
        !            69:       mp_size_t rsize;
        !            70:       mp_limb_t cy_limb;
        !            71:       mp_ptr rp, tp;
        !            72:       mp_size_t adj;
        !            73:
        !            74:       rsize = usize + vsize;
        !            75:       tp = (mp_ptr) TMP_ALLOC (rsize * BYTES_PER_MP_LIMB);
        !            76:       cy_limb = (usize >= vsize
        !            77:                 ? mpn_mul (tp, up, usize, vp, vsize)
        !            78:                 : mpn_mul (tp, vp, vsize, up, usize));
        !            79:
        !            80:       adj = cy_limb == 0;
        !            81:       rsize -= adj;
        !            82:       prec++;
        !            83:       if (rsize > prec)
        !            84:        {
        !            85:          tp += rsize - prec;
        !            86:          rsize = prec;
        !            87:        }
        !            88:       rp = r->_mp_d;
        !            89:       MPN_COPY (rp, tp, rsize);
        !            90:       r->_mp_exp = u->_mp_exp + v->_mp_exp - adj;
        !            91:       r->_mp_size = sign_product >= 0 ? rsize : -rsize;
        !            92:     }
        !            93:   TMP_FREE (marker);
        !            94: }