source/libs/mpfr/mpfr-3.1.3/src/si_op.c

   1 /* mpfr_add_si -- add a floating-point number with a machine integer
   2    mpfr_sub_si -- sub  a floating-point number with a machine integer
   3    mpfr_si_sub -- sub  a machine number with a floating-point number
   4
   5 Copyright 2004-2015 Free Software Foundation, Inc.
   6 Contributed by the AriC and Caramel projects, INRIA.
   7
   8 This file is part of the GNU MPFR Library.
   9
  10 The GNU MPFR Library is free software; you can redistribute it and/or modify
  11 it under the terms of the GNU Lesser General Public License as published by
  12 the Free Software Foundation; either version 3 of the License, or (at your
  13 option) any later version.
  14
  15 The GNU MPFR Library is distributed in the hope that it will be useful, but
  16 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  17 or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  18 License for more details.
  19
  20 You should have received a copy of the GNU Lesser General Public License
  21 along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
  22 http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
  23 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
  24
  25 #include "mpfr-impl.h"
  26
  27 int
  28 mpfr_add_si (mpfr_ptr y, mpfr_srcptr x, long int u, mpfr_rnd_t rnd_mode)
  29 {
  30   if (u >= 0)
  31     return mpfr_add_ui (y, x, u, rnd_mode);
  32   else
  33     return mpfr_sub_ui (y, x, -u, rnd_mode);
  34 }
  35
  36 int
  37 mpfr_sub_si (mpfr_ptr y, mpfr_srcptr x, long int u, mpfr_rnd_t rnd_mode)
  38 {
  39   if (u >= 0)
  40     return mpfr_sub_ui (y, x, u, rnd_mode);
  41   else
  42     return mpfr_add_ui (y, x, -u, rnd_mode);
  43 }
  44
  45 int
  46 mpfr_si_sub (mpfr_ptr y, long int u, mpfr_srcptr x, mpfr_rnd_t rnd_mode)
  47 {
  48   if (u >= 0)
  49     return mpfr_ui_sub (y, u, x, rnd_mode);
  50   else
  51     {
  52     int res = -mpfr_add_ui (y, x, -u, MPFR_INVERT_RND (rnd_mode));
  53     MPFR_CHANGE_SIGN (y);
  54     return res;
  55     }
  56 }
  57