niceSOFT/mpfr | Gitverse

src/fms.c
38 строк1 KB
Vincent Lefèvre
03 янв 2018, 13:53
03 янв 2018, 13:532fce388
/* mpfr_fms -- Floating multiply-subtract

Copyright 2001-2002, 2004, 2006-2018 Free Software Foundation, Inc.
Contributed by the AriC and Caramba projects, INRIA.

This file is part of the GNU MPFR Library.

The GNU MPFR Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 3 of the License, or (at your
option) any later version.

The GNU MPFR Library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
License for more details.

You should have received a copy of the GNU Lesser General Public License
along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */

#include "mpfr-impl.h"

/* The fused-multiply-subtract (fms) of x, y and z is defined by:
   fms(x,y,z)= x*y - z
   Note: this is neither in IEEE 754-2008, nor in LIA-2, but both the
   PowerPC and the Itanium define fms as x*y - z.
*/
int
mpfr_fms (mpfr_ptr s, mpfr_srcptr x, mpfr_srcptr y, mpfr_srcptr z,
          mpfr_rnd_t rnd_mode)
{
  mpfr_t minus_z;

  MPFR_ALIAS (minus_z, z, -MPFR_SIGN(z), MPFR_EXP(z));
  return mpfr_fma (s, x, y, minus_z, rnd_mode);
}