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Annotation of OpenXM_contrib/gmp/mpf/mul.c, Revision 1.1.1.3

1.1       maekawa     1: /* mpf_mul -- Multiply two floats.
                      2:
1.1.1.3 ! ohara       3: Copyright 1993, 1994, 1996, 2001 Free Software Foundation, Inc.
1.1       maekawa     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
1.1.1.2   maekawa     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
1.1       maekawa    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
1.1.1.2   maekawa    14: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
1.1       maekawa    15: License for more details.
                     16:
1.1.1.2   maekawa    17: You should have received a copy of the GNU Lesser General Public License
1.1       maekawa    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: mpf_mul (mpf_ptr r, mpf_srcptr u, mpf_srcptr v)
                     27: {
                     28:   mp_srcptr up, vp;
                     29:   mp_size_t usize, vsize;
                     30:   mp_size_t sign_product;
                     31:   mp_size_t prec = r->_mp_prec;
                     32:   TMP_DECL (marker);
                     33:
                     34:   TMP_MARK (marker);
                     35:   usize = u->_mp_size;
                     36:   vsize = v->_mp_size;
                     37:   sign_product = usize ^ vsize;
                     38:
                     39:   usize = ABS (usize);
                     40:   vsize = ABS (vsize);
                     41:
                     42:   up = u->_mp_d;
                     43:   vp = v->_mp_d;
                     44:   if (usize > prec)
                     45:     {
                     46:       up += usize - prec;
                     47:       usize = prec;
                     48:     }
                     49:   if (vsize > prec)
                     50:     {
                     51:       vp += vsize - prec;
                     52:       vsize = prec;
                     53:     }
                     54:
                     55:   if (usize == 0 || vsize == 0)
                     56:     {
                     57:       r->_mp_size = 0;
                     58:       r->_mp_exp = 0;          /* ??? */
                     59:     }
                     60:   else
                     61:     {
                     62:       mp_size_t rsize;
                     63:       mp_limb_t cy_limb;
                     64:       mp_ptr rp, tp;
                     65:       mp_size_t adj;
                     66:
                     67:       rsize = usize + vsize;
                     68:       tp = (mp_ptr) TMP_ALLOC (rsize * BYTES_PER_MP_LIMB);
                     69:       cy_limb = (usize >= vsize
                     70:                 ? mpn_mul (tp, up, usize, vp, vsize)
                     71:                 : mpn_mul (tp, vp, vsize, up, usize));
                     72:
                     73:       adj = cy_limb == 0;
                     74:       rsize -= adj;
                     75:       prec++;
                     76:       if (rsize > prec)
                     77:        {
                     78:          tp += rsize - prec;
                     79:          rsize = prec;
                     80:        }
                     81:       rp = r->_mp_d;
                     82:       MPN_COPY (rp, tp, rsize);
                     83:       r->_mp_exp = u->_mp_exp + v->_mp_exp - adj;
                     84:       r->_mp_size = sign_product >= 0 ? rsize : -rsize;
                     85:     }
                     86:   TMP_FREE (marker);
                     87: }