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

1.1       maekawa     1: /* mpz_mul -- Multiply two integers.
                      2:
                      3: Copyright (C) 1991, 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: #ifndef BERKELEY_MP
                     26: void
                     27: #if __STDC__
                     28: mpz_mul (mpz_ptr w, mpz_srcptr u, mpz_srcptr v)
                     29: #else
                     30: mpz_mul (w, u, v)
                     31:      mpz_ptr w;
                     32:      mpz_srcptr u;
                     33:      mpz_srcptr v;
                     34: #endif
                     35: #else /* BERKELEY_MP */
                     36: void
                     37: #if __STDC__
                     38: mult (mpz_srcptr u, mpz_srcptr v, mpz_ptr w)
                     39: #else
                     40: mult (u, v, w)
                     41:      mpz_srcptr u;
                     42:      mpz_srcptr v;
                     43:      mpz_ptr w;
                     44: #endif
                     45: #endif /* BERKELEY_MP */
                     46: {
                     47:   mp_size_t usize = u->_mp_size;
                     48:   mp_size_t vsize = v->_mp_size;
                     49:   mp_size_t wsize;
                     50:   mp_size_t sign_product;
                     51:   mp_ptr up, vp;
                     52:   mp_ptr wp;
                     53:   mp_ptr free_me = NULL;
                     54:   size_t free_me_size;
                     55:   mp_limb_t cy_limb;
                     56:   TMP_DECL (marker);
                     57:
                     58:   TMP_MARK (marker);
                     59:   sign_product = usize ^ vsize;
                     60:   usize = ABS (usize);
                     61:   vsize = ABS (vsize);
                     62:
                     63:   if (usize < vsize)
                     64:     {
                     65:       /* Swap U and V.  */
                     66:       {const __mpz_struct *t = u; u = v; v = t;}
                     67:       {mp_size_t t = usize; usize = vsize; vsize = t;}
                     68:     }
                     69:
                     70:   up = u->_mp_d;
                     71:   vp = v->_mp_d;
                     72:   wp = w->_mp_d;
                     73:
                     74:   /* Ensure W has space enough to store the result.  */
                     75:   wsize = usize + vsize;
                     76:   if (w->_mp_alloc < wsize)
                     77:     {
                     78:       if (wp == up || wp == vp)
                     79:        {
                     80:          free_me = wp;
                     81:          free_me_size = w->_mp_alloc;
                     82:        }
                     83:       else
                     84:        (*_mp_free_func) (wp, w->_mp_alloc * BYTES_PER_MP_LIMB);
                     85:
                     86:       w->_mp_alloc = wsize;
                     87:       wp = (mp_ptr) (*_mp_allocate_func) (wsize * BYTES_PER_MP_LIMB);
                     88:       w->_mp_d = wp;
                     89:     }
                     90:   else
                     91:     {
                     92:       /* Make U and V not overlap with W.  */
                     93:       if (wp == up)
                     94:        {
                     95:          /* W and U are identical.  Allocate temporary space for U.  */
                     96:          up = (mp_ptr) TMP_ALLOC (usize * BYTES_PER_MP_LIMB);
                     97:          /* Is V identical too?  Keep it identical with U.  */
                     98:          if (wp == vp)
                     99:            vp = up;
                    100:          /* Copy to the temporary space.  */
                    101:          MPN_COPY (up, wp, usize);
                    102:        }
                    103:       else if (wp == vp)
                    104:        {
                    105:          /* W and V are identical.  Allocate temporary space for V.  */
                    106:          vp = (mp_ptr) TMP_ALLOC (vsize * BYTES_PER_MP_LIMB);
                    107:          /* Copy to the temporary space.  */
                    108:          MPN_COPY (vp, wp, vsize);
                    109:        }
                    110:     }
                    111:
                    112:   if (vsize == 0)
                    113:     {
                    114:       wsize = 0;
                    115:     }
                    116:   else
                    117:     {
                    118:       cy_limb = mpn_mul (wp, up, usize, vp, vsize);
                    119:       wsize = usize + vsize;
                    120:       wsize -= cy_limb == 0;
                    121:     }
                    122:
                    123:   w->_mp_size = sign_product < 0 ? -wsize : wsize;
                    124:   if (free_me != NULL)
                    125:     (*_mp_free_func) (free_me, free_me_size * BYTES_PER_MP_LIMB);
                    126:   TMP_FREE (marker);
                    127: }