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
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
|
/* mpfr_set_f -- set a MPFR number from a GNU MPF number
Copyright (C) 1999, 2000, 2001 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 <stdio.h>
#include "gmp.h"
#include "gmp-impl.h"
#include "longlong.h"
#include "mpfr.h"
#include "mpfr-impl.h"
int
mpfr_set_f (mpfr_ptr y, mpf_srcptr x, mp_rnd_t rnd_mode)
{
mp_limb_t *my, *mx, *tmp;
unsigned long cnt, sx, sy;
int inexact;
TMP_DECL(marker);
if (SIZ(x) * MPFR_SIGN(y) < 0)
MPFR_CHANGE_SIGN (y);
MPFR_CLEAR_FLAGS (y);
sx = ABS(SIZ(x)); /* number of limbs of the mantissa of x */
sy = 1 + (MPFR_PREC(y) - 1) / BITS_PER_MP_LIMB;
my = MPFR_MANT(y);
mx = PTR(x);
if (sx == 0) /* x is zero */
{
MPFR_SET_ZERO(y);
return 0; /* 0 is exact */
}
count_leading_zeros(cnt, mx[sx - 1]);
if (sy <= sx) /* we may have to round even when sy = sx */
{
unsigned long xprec = sx * BITS_PER_MP_LIMB;
TMP_MARK(marker);
tmp = (mp_limb_t*) TMP_ALLOC(xprec);
if (cnt)
mpn_lshift(tmp, mx, sx, cnt);
else
MPN_COPY(tmp, mx, sx);
mpfr_round_raw (my, tmp, xprec, (SIZ(x)<0), MPFR_PREC(y), rnd_mode,
&inexact);
TMP_FREE(marker);
}
else
{
if (cnt)
mpn_lshift(my + sy - sx, mx, sx, cnt);
else
MPN_COPY(my + sy - sx, mx, sy);
MPN_ZERO(my, sy - sx);
/* no rounding necessary, since y has a larger mantissa */
inexact = 0;
}
MPFR_EXP(y) = EXP(x) * BITS_PER_MP_LIMB - cnt;
return inexact;
}
|
