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

1.1       ohara       1: /* mpz_divexact_ui -- exact division mpz by ulong.
                      2:
                      3: Copyright 2001, 2002 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 Lesser General Public License as published by
                      9: the Free Software Foundation; either version 2.1 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 Lesser General Public
                     15: License for more details.
                     16:
                     17: You should have received a copy of the GNU Lesser 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:
                     23: #include "gmp.h"
                     24: #include "gmp-impl.h"
                     25:
                     26: void
                     27: mpz_divexact_ui (mpz_ptr dst, mpz_srcptr src, unsigned long divisor)
                     28: {
                     29:   mp_size_t  size, abs_size;
                     30:   mp_ptr     dst_ptr;
                     31:
                     32:   if (divisor == 0)
                     33:     DIVIDE_BY_ZERO;
                     34:
                     35:   /* For nails don't try to be clever if d is bigger than a limb, just fake
                     36:      up an mpz_t and go to the main mpz_divexact.  */
                     37:   if (divisor > GMP_NUMB_MAX)
                     38:     {
                     39:       mp_limb_t  dlimbs[2];
                     40:       mpz_t      dz;
                     41:       ALLOC(dz) = 2;
                     42:       PTR(dz) = dlimbs;
                     43:       mpz_set_ui (dz, divisor);
                     44:       mpz_divexact (dst, src, dz);
                     45:       return;
                     46:     }
                     47:
                     48:   size = SIZ(src);
                     49:   if (size == 0)
                     50:     {
                     51:       SIZ(dst) = 0;
                     52:       return;
                     53:     }
                     54:   abs_size = ABS (size);
                     55:
                     56:   MPZ_REALLOC (dst, abs_size);
                     57:   dst_ptr = PTR(dst);
                     58:
                     59:   MPN_DIVREM_OR_DIVEXACT_1 (dst_ptr, PTR(src), abs_size, (mp_limb_t) divisor);
                     60:   abs_size -= (dst_ptr[abs_size-1] == 0);
                     61:   SIZ(dst) = (size >= 0 ? abs_size : -abs_size);
                     62: }