1 /* mpfr_fms -- Floating multiply-subtract
2
3 Copyright 2001-2002, 2004, 2006-2023 Free Software Foundation, Inc.
4 Contributed by the AriC and Caramba projects, INRIA.
5
6 This file is part of the GNU MPFR Library.
7
8 The GNU MPFR 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 MPFR 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 MPFR Library; see the file COPYING.LESSER. If not, see
20 https://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
21 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
22
23 #include "mpfr-impl.h"
24
25 /* The fused-multiply-subtract (fms) of x, y and z is defined by:
26 fms(x,y,z)= x*y - z
27 Note: this is neither in IEEE 754-2008, nor in LIA-2, but both the
28 PowerPC and the Itanium define fms as x*y - z.
29 */
30 int
mpfr_fms(mpfr_ptr s,mpfr_srcptr x,mpfr_srcptr y,mpfr_srcptr z,mpfr_rnd_t rnd_mode)31 mpfr_fms (mpfr_ptr s, mpfr_srcptr x, mpfr_srcptr y, mpfr_srcptr z,
32 mpfr_rnd_t rnd_mode)
33 {
34 mpfr_t minus_z;
35
36 MPFR_ALIAS (minus_z, z, -MPFR_SIGN(z), MPFR_EXP(z));
37 return mpfr_fma (s, x, y, minus_z, rnd_mode);
38 }
39