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Annotation of OpenXM_contrib/gmp/mpf/mul.c, Revision 1.1.1.1

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: }