1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
|
/* mpfr_sub_ui -- subtract a floating-point number and a machine integer
Copyright 2000, 2001, 2002 Free Software Foundation, Inc.
This file is part of the MPFR Library.
The 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 2.1 of the License, or (at your
option) any later version.
The 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 MPFR Library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA. */
#include "gmp.h"
#include "gmp-impl.h"
#include "longlong.h"
#include "mpfr.h"
#include "mpfr-impl.h"
int
mpfr_sub_ui (mpfr_ptr y, mpfr_srcptr x, unsigned long int u, mp_rnd_t rnd_mode)
{
if (u) /* if u=0, do nothing */
{
mpfr_t uu;
mp_limb_t up[1];
unsigned long cnt;
int inex;
MPFR_INIT1(up, uu, BITS_PER_MP_LIMB, 1);
count_leading_zeros(cnt, (mp_limb_t) u);
*up = (mp_limb_t) u << cnt;
MPFR_EXP(uu) = BITS_PER_MP_LIMB - cnt;
/* Optimization note: Exponent operations may be removed
if mpfr_sub works even when uu is out-of-range. */
mpfr_save_emin_emax();
inex = mpfr_sub(y, x, uu, rnd_mode);
MPFR_RESTORE_RET(inex, y, rnd_mode);
}
else
return mpfr_set (y, x, rnd_mode);
}
|
