contrib/gmp/mpz/set_si.c

   1 /* mpz_set_si(dest,val) -- Assign DEST with a small value VAL.
   2
   3 Copyright 1991, 1993, 1994, 1995, 2000, 2001, 2002 Free Software Foundation,
   4 Inc.
   5
   6 This file is part of the GNU MP Library.
   7
   8 The GNU MP Library is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU Lesser General Public License as published by
  10 the Free Software Foundation; either version 3 of the License, or (at your
  11 option) any later version.
  12
  13 The GNU MP Library is distributed in the hope that it will be useful, but
  14 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  15 or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  16 License for more details.
  17
  18 You should have received a copy of the GNU Lesser General Public License
  19 along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.  */
  20
  21 #include "gmp.h"
  22 #include "gmp-impl.h"
  23
  24 void
  25 mpz_set_si (mpz_ptr dest, signed long int val)
  26 {
  27   mp_size_t size;
  28   mp_limb_t vl;
  29
  30   vl = (mp_limb_t) ABS_CAST (unsigned long int, val);
  31
  32   dest->_mp_d[0] = vl & GMP_NUMB_MASK;
  33   size = vl != 0;
  34
  35 #if GMP_NAIL_BITS != 0
  36   if (vl > GMP_NUMB_MAX)
  37     {
  38       MPZ_REALLOC (dest, 2);
  39       dest->_mp_d[1] = vl >> GMP_NUMB_BITS;
  40       size = 2;
  41     }
  42 #endif
  43
  44   dest->_mp_size = val >= 0 ? size : -size;
  45 }