1
/* mpfr_nextabove, mpfr_nextbelow, mpfr_nexttoward -- next representable
4
Copyright 1999, 2001, 2002, 2003, 2004, 2005 Free Software Foundation.
5
Contributed by the Spaces project, INRIA Lorraine.
7
This file is part of the MPFR Library.
9
The MPFR Library is free software; you can redistribute it and/or modify
10
it under the terms of the GNU Lesser General Public License as published by
11
the Free Software Foundation; either version 2.1 of the License, or (at your
12
option) any later version.
14
The MPFR Library is distributed in the hope that it will be useful, but
15
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
16
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
17
License for more details.
19
You should have received a copy of the GNU Lesser General Public License
20
along with the MPFR Library; see the file COPYING.LIB. If not, write to
21
the Free Software Foundation, Inc., 51 Franklin Place, Fifth Floor, Boston,
22
MA 02110-1301, USA. */
24
#include "mpfr-impl.h"
27
mpfr_nexttozero (mpfr_ptr x)
29
if (MPFR_UNLIKELY(MPFR_IS_INF(x)))
32
mpfr_setmax (x, __gmpfr_emax);
35
else if (MPFR_UNLIKELY( MPFR_IS_ZERO(x) ))
38
mpfr_setmin (x, __gmpfr_emin);
46
xn = MPFR_LIMB_SIZE (x);
47
MPFR_UNSIGNED_MINUS_MODULO (sh, MPFR_PREC(x));
49
mpn_sub_1 (xp, xp, xn, MPFR_LIMB_ONE << sh);
50
if (MPFR_UNLIKELY( MPFR_LIMB_MSB(xp[xn-1]) == 0) )
51
{ /* was an exact power of two: not normalized any more */
52
mp_exp_t exp = MPFR_EXP (x);
53
if (MPFR_UNLIKELY(exp == __gmpfr_emin))
58
MPFR_SET_EXP (x, exp - 1);
59
xp[0] = MP_LIMB_T_MAX << sh;
60
for (i = 1; i < xn; i++)
61
xp[i] = MP_LIMB_T_MAX;
68
mpfr_nexttoinf (mpfr_ptr x)
70
if (MPFR_UNLIKELY(MPFR_IS_INF(x)))
72
else if (MPFR_UNLIKELY(MPFR_IS_ZERO(x)))
73
mpfr_setmin (x, __gmpfr_emin);
80
xn = MPFR_LIMB_SIZE (x);
81
MPFR_UNSIGNED_MINUS_MODULO (sh, MPFR_PREC(x));
83
if (MPFR_UNLIKELY( mpn_add_1 (xp, xp, xn, MPFR_LIMB_ONE << sh)) )
86
mp_exp_t exp = MPFR_EXP (x);
87
if (MPFR_UNLIKELY(exp == __gmpfr_emax))
91
MPFR_SET_EXP (x, exp + 1);
92
xp[xn-1] = MPFR_LIMB_HIGHBIT;
99
mpfr_nextabove (mpfr_ptr x)
101
if (MPFR_UNLIKELY(MPFR_IS_NAN(x)))
103
__gmpfr_flags |= MPFR_FLAGS_NAN;
113
mpfr_nextbelow (mpfr_ptr x)
115
if (MPFR_UNLIKELY(MPFR_IS_NAN(x)))
117
__gmpfr_flags |= MPFR_FLAGS_NAN;
128
mpfr_nexttoward (mpfr_ptr x, mpfr_srcptr y)
132
if (MPFR_UNLIKELY(MPFR_IS_NAN(x)))
134
__gmpfr_flags |= MPFR_FLAGS_NAN;
137
else if (MPFR_UNLIKELY(MPFR_IS_NAN(x) || MPFR_IS_NAN(y)))
140
__gmpfr_flags |= MPFR_FLAGS_NAN;