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
|
/* Definitions of target machine for GNU compiler, for IBM S/390
Copyright (C) 1999, 2000, 2001, 2007, 2008 and 2009
Free Software Foundation, Inc.
Contributed by Hartmut Penner (hpenner@de.ibm.com) and
Ulrich Weigand (uweigand@de.ibm.com).
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.
GCC 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 General Public License
for more details.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
#define EXPD(fp) (((fp.l.i[0]) >> 16) & 0x7FFF)
#define EXPONENT_BIAS 16383
#define MANTISSA_BITS 112
#define PRECISION (MANTISSA_BITS + 1)
#define SIGNBIT 0x80000000
#define SIGND(fp) ((fp.l.i[0]) & SIGNBIT)
#define MANTD_HIGH_LL(fp) ((fp.ll[0] & HIGH_LL_FRAC_MASK) | HIGH_LL_UNIT_BIT)
#define MANTD_LOW_LL(fp) (fp.ll[1])
#define FRACD_ZERO_P(fp) (!fp.ll[1] && !(fp.ll[0] & HIGH_LL_FRAC_MASK))
#define HIGH_LL_FRAC_BITS 48
#define HIGH_LL_UNIT_BIT ((UDItype_x)1 << HIGH_LL_FRAC_BITS)
#define HIGH_LL_FRAC_MASK (HIGH_LL_UNIT_BIT - 1)
typedef int DItype_x __attribute__ ((mode (DI)));
typedef unsigned int UDItype_x __attribute__ ((mode (DI)));
typedef int SItype_x __attribute__ ((mode (SI)));
typedef unsigned int USItype_x __attribute__ ((mode (SI)));
union double_long {
long double d;
struct {
SItype_x i[4]; /* 32 bit parts: 0 upper ... 3 lowest */
} l;
UDItype_x ll[2]; /* 64 bit parts: 0 upper, 1 lower */
};
UDItype_x __fixunstfdi (long double a1);
/* convert double to unsigned int */
UDItype_x
__fixunstfdi (long double a1)
{
register union double_long dl1;
register int exp;
register UDItype_x l;
dl1.d = a1;
/* +/- 0, denormalized, negative */
if (!EXPD (dl1) || SIGND(dl1))
return 0;
/* The exponent - considered the binary point at the right end of
the mantissa. */
exp = EXPD (dl1) - EXPONENT_BIAS - MANTISSA_BITS;
/* number < 1: If the mantissa would need to be right-shifted more bits than
its size (plus the implied one bit on the left) the result would be
zero. */
if (exp <= -PRECISION)
return 0;
/* NaN: All exponent bits set and a nonzero fraction. */
if ((EXPD(dl1) == 0x7fff) && !FRACD_ZERO_P (dl1))
return 0x0ULL;
/* One extra bit is needed for the unit bit which is appended by
MANTD_HIGH_LL on the left of the matissa. */
exp += HIGH_LL_FRAC_BITS + 1;
/* If the result would still need a left shift it will be too large
to be represented. */
if (exp > 0)
return 0xFFFFFFFFFFFFFFFFULL;
l = MANTD_LOW_LL (dl1) >> (HIGH_LL_FRAC_BITS + 1)
| MANTD_HIGH_LL (dl1) << (64 - (HIGH_LL_FRAC_BITS + 1));
return l >> -exp;
}
|
