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Annotation of OpenXM_contrib/gmp/mpz/mul.c, Revision 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: }