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
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
|
/* mpfr_mul_ui -- multiply a floating-point number by a machine integer
Copyright (C) 1999 Free Software Foundation.
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 Library General Public License as published by
the Free Software Foundation; either version 2 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 Library General Public
License for more details.
You should have received a copy of the GNU Library 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"
#define ONE ((mp_limb_t) 1)
void
#if __STDC__
mpfr_mul_ui (mpfr_ptr y, mpfr_srcptr x, unsigned long int u, mp_rnd_t rnd_mode)
#else
mpfr_mul_ui (y, x, u, rnd_mode)
mpfr_ptr y;
mpfr_srcptr x;
unsigned long int u;
mp_rnd_t rnd_mode;
#endif
{
mp_limb_t carry, *my, *old_my, *my2;
unsigned long xsize, ysize, cnt, dif, ex, c;
long int sh;
TMP_DECL(marker);
if (MPFR_IS_NAN(x))
{
MPFR_CLEAR_FLAGS(y);
MPFR_SET_NAN(y);
return;
}
if (MPFR_IS_INF(x))
{
MPFR_CLEAR_FLAGS(y);
if (u)
{
MPFR_SET_INF(y);
if (MPFR_SIGN(y) != MPFR_SIGN(x)) { MPFR_CHANGE_SIGN(y); }
return;
}
else { MPFR_SET_NAN(y); return; }
}
if (MPFR_IS_ZERO(x) || !u)
{
MPFR_CLEAR_FLAGS(y); MPFR_SET_ZERO(y); return;
}
MPFR_CLEAR_FLAGS(y);
TMP_MARK(marker);
my = MPFR_MANT(y); ex = MPFR_EXP(x);
ysize = (MPFR_PREC(y) - 1) / BITS_PER_MP_LIMB + 1;
xsize = (MPFR_PREC(x) - 1) / BITS_PER_MP_LIMB + 1;
old_my = my;
if (ysize < xsize)
{
my = (mp_ptr) TMP_ALLOC (xsize * BYTES_PER_MP_LIMB);
dif = 0;
}
else
{
dif = ysize - xsize;
MPN_ZERO (my, dif);
}
carry = mpn_mul_1 (my + dif, MPFR_MANT(x), xsize, u);
/* WARNING: count_leading_zeros is undefined for carry=0 */
if (carry)
count_leading_zeros(cnt, carry);
else
cnt = BITS_PER_MP_LIMB;
/* BITS_PER_MP_LIMB - cnt is the number of significant bits in the carry */
/* the first (BITS_PER_MP_LIMB-cnt) bits of the result are in carry,
the remaining bits are in my[dif+xsize-1] .. my[dif] */
/* Warning: if all significant bits are in the carry, one has to
be careful */
if (cnt + MPFR_PREC(y) < BITS_PER_MP_LIMB)
{
/* Quick 'n dirty */
if (xsize > ysize) {
my2 = (mp_ptr) TMP_ALLOC ((xsize + 1) * BYTES_PER_MP_LIMB);
my2[xsize] = mpn_lshift(my2, my, xsize, cnt)
| (carry << (cnt ? BITS_PER_MP_LIMB - cnt : 0));
}
else {
my2 = (mp_ptr) TMP_ALLOC ((ysize + 1) * BYTES_PER_MP_LIMB);
my2[ysize] = mpn_lshift(my2, my, ysize, cnt)
| (carry << (cnt ? BITS_PER_MP_LIMB - cnt : 0));
}
my = my2; ex += BITS_PER_MP_LIMB - cnt;
carry = 0; cnt = BITS_PER_MP_LIMB;
}
/* as we already have (BITS_PER_MP_LIMB-cnt) bits in carry,
we need only prec(y) - (BITS_PER_MP_LIMB-cnt) more bits
from those in my[dif+xsize-1] .. my[dif],
and we want to store them in my[ysize-1] .. my[ysize].
Warning: the number of limbs used by x and the lower part
of y may differ */
sh = ysize - (MPFR_PREC(y) + cnt - 1) / BITS_PER_MP_LIMB;
c = mpfr_round_raw (my + sh, my + dif, MPFR_PREC(x), (MPFR_SIGN(x) < 0),
MPFR_PREC(y) - BITS_PER_MP_LIMB + cnt, rnd_mode, NULL);
/* now the high (BITS_PER_MP_LIMB-cnt) bits of the result are in carry,
and the remaining (yprec-BITS_PER_MP_LIMB+cnt) ones in
my[ysize-1] .. my[sh] */
/* If cnt = 1111111111111 and c = 1 we shall get depressed */
if (c && (carry == (ONE << (cnt ? BITS_PER_MP_LIMB - cnt : 0))
- 1))
{
cnt--;
mpn_rshift(my, my, ysize, BITS_PER_MP_LIMB - cnt);
my[ysize - 1] |= ((mp_limb_t) 1) << (BITS_PER_MP_LIMB - 1);
}
else
{
/* Warning: mpn_rshift is undefined for shift=0 */
if (cnt != BITS_PER_MP_LIMB)
mpn_rshift(my, my, ysize, BITS_PER_MP_LIMB - cnt);
my[ysize - 1] |= carry << cnt;
}
MPFR_EXP(y) = ex + BITS_PER_MP_LIMB - cnt;
if (ysize < xsize)
MPN_COPY(old_my, my, ysize);
/* set sign */
if (MPFR_SIGN(y) * MPFR_SIGN(x) < 0)
MPFR_CHANGE_SIGN(y);
TMP_FREE(marker);
}
|
